Merge changes from topic 'star-labels-part-1'

* changes: Support star labels Add factory for ChangeResource
2016-05-09 15:15:09 +00:00
parent 40763ab67c 9e972ccb44
commit edb6705cbe
40 changed files with 1165 additions and 126 deletions
--- a/Documentation/dev-stars.txt
+++ b/Documentation/dev-stars.txt
@@ -0,0 +1,73 @@
+= Gerrit Code Review - Stars
+
+== Description
+
+Changes can be starred with labels that behave like private hashtags.
+Any label can be applied to a change, but these labels are only visible
+to the user for which the labels have been set.
+
+Stars allow users to categorize changes by self-defined criteria and
+then build link:user-dashboards.html[dashboards] for them by making use
+of the link:#query-stars[star query operators].
+
+[[star-api]]
+== Star API
+
+The link:rest-api-accounts.html#star-endpoints[star REST API] supports:
+
+* link:rest-api-accounts.html#get-stars[
+  get star labels from a change]
+* link:rest-api-accounts.html#set-stars[
+  update star labels on a change]
+* link:rest-api-accounts.html#get-starred-changes[
+  list changes that are starred by any label]
+
+Star labels are also included in
+link:rest-api-changes.html#change-info[ChangeInfo] entities that are
+returned by the link:rest-api-changes.html[changes REST API].
+
+There are link:rest-api-accounts.html#default-star-endpoints[
+additional REST endpoints] for the link:#default-star[default star].
+
+Only the link:#default-star[default star] is shown in the WebUi and
+can be updated from there. Other stars do not show up in the WebUi.
+
+[[default-star]]
+== Default Star
+
+If the default star is set by a user, this user is automatically
+notified by email whenever updates are made to that change.
+
+The default star is the star that is shown in the WebUI and which can
+be updated from there.
+
+The default star is represented by the special star label 'star'.
+
+[[query-stars]]
+== Query Stars
+
+There are several query operators to find changes with stars:
+
+* link:user-search.html#star[star:<LABEL>]:
+  Matches any change that was starred by the current user with the
+  label `<LABEL>`.
+* link:user-search.html#has-stars[has:stars]:
+  Matches any change that was starred by the current user with any
+  label.
+* link:user-search.html#is-starred[is:starred] /
+  link:user-search.html#has-star[has:star]:
+  Matches any change that was starred by the current user with the
+  link:#default-star[default star].
+
+[[syntax]]
+== Syntax
+
+Star labels cannot contain whitespace characters. All other characters
+are allowed.
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------
--- a/Documentation/index.txt
+++ b/Documentation/index.txt
@@ -68,6 +68,7 @@
 .. link:dev-build-plugins.html[Building Gerrit plugins]
 .. link:js-api.html[JavaScript Plugin API]
 .. link:config-validation.html[Validation Interfaces]
+.. link:dev-stars.html[Starring Changes]
 . link:dev-design.html[System Design]
 . link:i18n-readme.html[i18n Support]

--- a/Documentation/rest-api-accounts.txt
+++ b/Documentation/rest-api-accounts.txt
@@ -1573,16 +1573,19 @@ The result is sorted by project name in ascending order.
  ]
 ----

-[[get-starred-changes]]
-=== Get Starred Changes
+[[default-star-endpoints]]
+== Default Star Endpoints
+
+[[get-changes-with-default-star]]
+=== Get Changes With Default Star
 --
 'GET /accounts/link:#account-id[\{account-id\}]/starred.changes'
 --

-Gets the changes starred by the identified user account. This
-URL endpoint is functionally identical to the changes query
-`GET /changes/?q=is:starred`. The result is a list of
-link:rest-api-changes.html#change-info[ChangeInfo] entities.
+Gets the changes that were starred with the default star by the
+identified user account. This URL endpoint is functionally identical
+to the changes query `GET /changes/?q=is:starred`. The result is a list
+of link:rest-api-changes.html#change-info[ChangeInfo] entities.

 .Request
 ----
@@ -1607,6 +1610,9 @@ link:rest-api-changes.html#change-info[ChangeInfo] entities.
      "created": "2013-02-01 09:59:32.126000000",
      "updated": "2013-02-21 11:16:36.775000000",
      "starred": true,
+      "stars": [
+        "star"
+      ],
      "mergeable": true,
      "submittable": false,
      "insertions": 145,
@@ -1620,14 +1626,15 @@ link:rest-api-changes.html#change-info[ChangeInfo] entities.
 ----

 [[star-change]]
-=== Star Change
+=== Put Default Star On Change
 --
 'PUT /accounts/link:#account-id[\{account-id\}]/starred.changes/link:rest-api-changes.html#change-id[\{change-id\}]'
 --

-Star a change. Starred changes are returned for the search query
-`is:starred` or `starredby:USER` and automatically notify the user
-whenever updates are made to the change.
+Star a change with the default label. Changes starred with the default
+label are returned for the search query `is:starred` or `starredby:USER`
+and automatically notify the user whenever updates are made to the
+change.

 .Request
 ----
@@ -1640,12 +1647,12 @@ whenever updates are made to the change.
 ----

 [[unstar-change]]
-=== Unstar Change
+=== Remove Default Star From Change
 --
 'DELETE /accounts/link:#account-id[\{account-id\}]/starred.changes/link:rest-api-changes.html#change-id[\{change-id\}]'
 --

-Unstar a change. Removes the starred flag, stopping notifications.
+Remove the default star label from a change. This stops notifications.

 .Request
 ----
@@ -1657,6 +1664,131 @@ Unstar a change. Removes the starred flag, stopping notifications.
  HTTP/1.1 204 No Content
 ----

+[[star-endpoints]]
+== Star Endpoints
+
+[[get-starred-changes]]
+=== Get Starred Changes
+--
+'GET /accounts/link:#account-id[\{account-id\}]/stars.changes'
+--
+
+Gets the changes that were starred with any label by the identified
+user account. This URL endpoint is functionally identical to the
+changes query `GET /changes/?q=has:stars`. The result is a list of
+link:rest-api-changes.html#change-info[ChangeInfo] entities.
+
+.Request
+----
+  GET /a/accounts/self/stars.changes
+----
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json; charset=UTF-8
+
+  )]}'
+  [
+    {
+      "id": "myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940",
+      "project": "myProject",
+      "branch": "master",
+      "change_id": "I8473b95934b5732ac55d26311a706c9c2bde9940",
+      "subject": "Implementing Feature X",
+      "status": "NEW",
+      "created": "2013-02-01 09:59:32.126000000",
+      "updated": "2013-02-21 11:16:36.775000000",
+      "stars": [
+        "ignore",
+        "risky"
+      ],
+      "mergeable": true,
+      "submittable": false,
+      "insertions": 145,
+      "deletions": 12,
+      "_number": 3965,
+      "owner": {
+        "name": "John Doe"
+      }
+    }
+  ]
+----
+
+[[get-stars]]
+=== Get Star Labels From Change
+--
+'GET /accounts/link:#account-id[\{account-id\}]/stars.changes/link:rest-api-changes.html#change-id[\{change-id\}]'
+--
+
+Get star labels from a change.
+
+.Request
+----
+  GET /a/accounts/self/stars.changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940 HTTP/1.0
+----
+
+As response the star labels that the user applied on the change are
+returned. The labels are lexicographically sorted.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json; charset=UTF-8
+
+  )]
+  [
+    "blue",
+    "green",
+    "red"
+  ]
+----
+
+[[set-stars]]
+=== Update Star Labels On Change
+--
+'POST /accounts/link:#account-id[\{account-id\}]/stars.changes/link:rest-api-changes.html#change-id[\{change-id\}]'
+--
+
+Update star labels on a change. The star labels to be added/removed
+must be specified in the request body as link:#star-input[StarInput]
+entity. Starred changes are returned for the search query `has:stars`.
+
+.Request
+----
+  POST /a/accounts/self/stars.changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940 HTTP/1.0
+  Content-Type: application/json; charset=UTF-8
+
+  {
+    "add": [
+      "blue",
+      "red"
+    ],
+    "remove": [
+      "yellow"
+    ]
+  }
+----
+
+As response the star labels that the user applied on the change are
+returned. The labels are lexicographically sorted.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json; charset=UTF-8
+
+  )]
+  [
+    "blue",
+    "green",
+    "red"
+  ]
+----
+
 [[ids]]
 == IDs

@@ -2220,6 +2352,18 @@ user.
 |`valid`         ||Whether the SSH key is valid.
 |=============================

+[[stars-input]]
+=== StarsInput
+The `StarsInput` entity contains star labels that should be added to
+or removed from a change.
+
+[options="header",cols="1,^1,5"]
+|========================
+|Field Name ||Description
+|`add`      |optional|List of labels to add to the change.
+|`remove`   |optional|List of labels to remove from the change.
+|========================
+
 [[username-input]]
 === UsernameInput
 The `UsernameInput` entity contains information for setting the
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -4113,7 +4113,10 @@ updated.
 The link:rest-api.html#timestamp[timestamp] of when the change was
 submitted.
 |`starred`            |not set if `false`|
-Whether the calling user has starred this change.
+Whether the calling user has starred this change with the default label.
+|`stars`              |optional|
+A list of star labels that are applied by the calling user to this
+change. The labels are lexicographically sorted.
 |`reviewed`           |not set if `false`|
 Whether the change was reviewed by the calling user.
 Only set if link:#reviewed[reviewed] is requested.
--- a/Documentation/user-search.txt
+++ b/Documentation/user-search.txt
@@ -247,25 +247,43 @@ named exactly `Foo.java` and does not match `AbstractFoo.java`.
 Regular expression matching can be enabled by starting the string
 with `^`. In this mode `file:` is an alias of `path:` (see above).

+[[star]]
+star:'LABEL'::
+
+Matches any change that was starred by the current user with the label
+'LABEL'.
+
+E.g. if changes that are not interesting are marked with an `ignore`
+star, they could be filtered out by '-star:ignore'.
+
+'star:star' is the same as 'has:star' and 'is:starred'.
+
 [[has]]
 has:draft::
 +
 True if there is a draft comment saved by the current user.

+[[has-star]]
 has:star::
 +
-Same as 'is:starred', true if the change has been starred by the
-current user.
+Same as 'is:starred' and 'star:star', true if the change has been
+starred by the current user with the default label.
+
+[[has-stars]]
+has:stars::
+
+True if the change has been starred by the current user with any label.

 has:edit::
 +
 True if the change has inline edit created by the current user.

 [[is]]
+[[is-starred]]
 is:starred::
 +
 Same as 'has:star', true if the change has been starred by the
-current user.
+current user with the default label.

 is:watched::
 +
@@ -510,7 +528,7 @@ the change.  This flag is always added to any query.

 starredby:'USER'::
 +
-Matches changes that have been starred by 'USER'.
+Matches changes that have been starred by 'USER' with the default label.
 The special case `starredby:self` applies to the caller.

 watchedby:'USER'::
--- a/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -197,6 +197,9 @@ public abstract class AbstractDaemonTest {
  @Inject
  protected ChangeNoteUtil changeNoteUtil;

+  @Inject
+  protected ChangeResource.Factory changeResourceFactory;
+
  protected TestRepository<InMemoryRepository> testRepo;
  protected GerritServer server;
  protected TestAccount admin;
@@ -741,6 +744,6 @@ public abstract class AbstractDaemonTest {
    List<ChangeControl> ctls = changeFinder.find(
        changeId, atrScope.get().getUser());
    assertThat(ctls).hasSize(1);
-    return new ChangeResource(ctls.get(0));
+    return changeResourceFactory.create(ctls.get(0));
  }
 }
--- a/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/accounts/AccountIT.java
+++ b/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/accounts/AccountIT.java
@@ -23,20 +23,25 @@ import static com.google.gerrit.gpg.testutil.TestKeys.allValidKeys;
 import static com.google.gerrit.gpg.testutil.TestKeys.validKeyWithExpiration;
 import static com.google.gerrit.gpg.testutil.TestKeys.validKeyWithSecondUserId;
 import static com.google.gerrit.gpg.testutil.TestKeys.validKeyWithoutExpiration;
+import static com.google.gerrit.server.StarredChangesUtil.DEFAULT_LABEL;
 import static java.nio.charset.StandardCharsets.UTF_8;

 import com.google.common.base.Function;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.io.BaseEncoding;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.AccountCreator;
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.extensions.api.accounts.EmailInput;
+import com.google.gerrit.extensions.api.changes.StarsInput;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.GpgKeyInfo;
 import com.google.gerrit.extensions.common.SshKeyInfo;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
@@ -173,11 +178,65 @@ public class AccountIT extends AbstractDaemonTest {
    gApi.accounts()
        .self()
        .starChange(triplet);
-    assertThat(info(triplet).starred).isTrue();
+    ChangeInfo change = info(triplet);
+    assertThat(change.starred).isTrue();
+
    gApi.accounts()
        .self()
        .unstarChange(triplet);
-    assertThat(info(triplet).starred).isNull();
+    change = info(triplet);
+    assertThat(change.starred).isNull();
+  }
+
+  @Test
+  public void starUnstarChangeWithLabels() throws Exception {
+    PushOneCommit.Result r = createChange();
+    String triplet = project.get() + "~master~" + r.getChangeId();
+    assertThat(gApi.accounts().self().getStars(triplet)).isEmpty();
+    assertThat(gApi.accounts().self().getStarredChanges()).isEmpty();
+
+    gApi.accounts().self().setStars(triplet,
+        new StarsInput(ImmutableSet.of(DEFAULT_LABEL, "red", "blue")));
+    ChangeInfo change = info(triplet);
+    assertThat(change.starred).isTrue();
+    assertThat(gApi.accounts().self().getStars(triplet))
+        .containsExactly("blue", "red", DEFAULT_LABEL).inOrder();
+    List<ChangeInfo> starredChanges =
+        gApi.accounts().self().getStarredChanges();
+    assertThat(starredChanges).hasSize(1);
+    ChangeInfo starredChange = starredChanges.get(0);
+    assertThat(starredChange._number).isEqualTo(r.getChange().getId().get());
+    assertThat(starredChange.starred).isTrue();
+
+    gApi.accounts().self().setStars(triplet,
+        new StarsInput(ImmutableSet.of("yellow"),
+            ImmutableSet.of(DEFAULT_LABEL, "blue")));
+    change = info(triplet);
+    assertThat(change.starred).isNull();
+    assertThat(gApi.accounts().self().getStars(triplet)).containsExactly(
+        "red", "yellow").inOrder();
+    starredChanges = gApi.accounts().self().getStarredChanges();
+    assertThat(starredChanges).hasSize(1);
+    starredChange = starredChanges.get(0);
+    assertThat(starredChange._number).isEqualTo(r.getChange().getId().get());
+    assertThat(starredChange.starred).isNull();
+
+    setApiUser(user);
+    exception.expect(AuthException.class);
+    exception.expectMessage("not allowed to get stars of another account");
+    gApi.accounts().id(Integer.toString((admin.id.get()))).getStars(triplet);
+  }
+
+  @Test
+  public void starWithInvalidLabels() throws Exception {
+    PushOneCommit.Result r = createChange();
+    String triplet = project.get() + "~master~" + r.getChangeId();
+    exception.expect(BadRequestException.class);
+    exception.expectMessage(
+        "invalid labels: another invalid label, invalid label");
+    gApi.accounts().self().setStars(triplet,
+        new StarsInput(ImmutableSet.of(DEFAULT_LABEL, "invalid label", "blue",
+            "another invalid label")));
  }

  @Test
--- a/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -1174,6 +1174,6 @@ public class ChangeIT extends AbstractDaemonTest {
    List<ChangeControl> ctls = changeFinder.find(
        r.getChangeId(), atrScope.get().getUser());
    assertThat(ctls).hasSize(1);
-    return new ChangeResource(ctls.get(0));
+    return changeResourceFactory.create(ctls.get(0));
  }
 }
--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/accounts/AccountApi.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/accounts/AccountApi.java
@@ -14,11 +14,13 @@

 package com.google.gerrit.extensions.api.accounts;

+import com.google.gerrit.extensions.api.changes.StarsInput;
 import com.google.gerrit.extensions.client.DiffPreferencesInfo;
 import com.google.gerrit.extensions.client.EditPreferencesInfo;
 import com.google.gerrit.extensions.client.GeneralPreferencesInfo;
 import com.google.gerrit.extensions.client.ProjectWatchInfo;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.GpgKeyInfo;
 import com.google.gerrit.extensions.common.SshKeyInfo;
 import com.google.gerrit.extensions.restapi.NotImplementedException;
@@ -26,6 +28,7 @@ import com.google.gerrit.extensions.restapi.RestApiException;

 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;

 public interface AccountApi {
  AccountInfo get() throws RestApiException;
@@ -50,8 +53,12 @@ public interface AccountApi {
  void deleteWatchedProjects(List<String> in)
      throws RestApiException;

-  void starChange(String id) throws RestApiException;
-  void unstarChange(String id) throws RestApiException;
+  void starChange(String changeId) throws RestApiException;
+  void unstarChange(String changeId) throws RestApiException;
+  void setStars(String changeId, StarsInput input) throws RestApiException;
+  SortedSet<String> getStars(String changeId) throws RestApiException;
+  List<ChangeInfo> getStarredChanges() throws RestApiException;
+
  void addEmail(EmailInput input) throws RestApiException;

  List<SshKeyInfo> listSshKeys() throws RestApiException;
@@ -130,12 +137,28 @@ public interface AccountApi {
    }

    @Override
-    public void starChange(String id) throws RestApiException {
+    public void starChange(String changeId) throws RestApiException {
      throw new NotImplementedException();
    }

    @Override
-    public void unstarChange(String id) throws RestApiException {
+    public void unstarChange(String changeId) throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
+    public void setStars(String changeId, StarsInput input)
+        throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
+    public SortedSet<String> getStars(String changeId) throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
+    public List<ChangeInfo> getStarredChanges() throws RestApiException {
      throw new NotImplementedException();
    }

--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/StarsInput.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/StarsInput.java
@@ -0,0 +1,34 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.api.changes;
+
+import java.util.Set;
+
+public class StarsInput {
+  public Set<String> add;
+  public Set<String> remove;
+
+  public StarsInput() {
+  }
+
+  public StarsInput(Set<String> add) {
+    this.add = add;
+  }
+
+  public StarsInput(Set<String> add, Set<String> remove) {
+    this.add = add;
+    this.remove = remove;
+  }
+}
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/SearchSuggestOracle.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/SearchSuggestOracle.java
@@ -104,6 +104,8 @@ public class SearchSuggestOracle extends HighlightSuggestOracle {
    suggestions.add("has:draft");
    suggestions.add("has:edit");
    suggestions.add("has:star");
+    suggestions.add("has:stars");
+    suggestions.add("star:");

    suggestions.add("is:");
    suggestions.add("is:starred");
--- a/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -24,8 +24,10 @@ import static com.google.gerrit.server.index.change.ChangeField.PROJECT;
 import static com.google.gerrit.server.index.change.IndexRewriter.CLOSED_STATUSES;
 import static com.google.gerrit.server.index.change.IndexRewriter.OPEN_STATUSES;

+import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
+import com.google.common.collect.Multimap;
 import com.google.common.collect.Sets;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
@@ -35,6 +37,7 @@ import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.index.FieldDef.FillArgs;
@@ -116,6 +119,8 @@ public class LuceneChangeIndex implements ChangeIndex {
      ChangeField.REVIEWEDBY.getName();
  private static final String HASHTAG_FIELD =
      ChangeField.HASHTAG_CASE_AWARE.getName();
+  private static final String STAR_FIELD = ChangeField.STAR.getName();
+  @Deprecated
  private static final String STARREDBY_FIELD = ChangeField.STARREDBY.getName();

  static Term idTerm(ChangeData cd) {
@@ -420,6 +425,9 @@ public class LuceneChangeIndex implements ChangeIndex {
    if (fields.contains(STARREDBY_FIELD)) {
      decodeStarredBy(doc, cd);
    }
+    if (fields.contains(STAR_FIELD)) {
+      decodeStar(doc, cd);
+    }
    return cd;
  }

@@ -482,6 +490,7 @@ public class LuceneChangeIndex implements ChangeIndex {
    cd.setHashtags(hashtags);
  }

+  @Deprecated
  private void decodeStarredBy(Document doc, ChangeData cd) {
    IndexableField[] starredBy = doc.getFields(STARREDBY_FIELD);
    Set<Account.Id> accounts =
@@ -492,6 +501,19 @@ public class LuceneChangeIndex implements ChangeIndex {
    cd.setStarredBy(accounts);
  }

+  private void decodeStar(Document doc, ChangeData cd) {
+    IndexableField[] star = doc.getFields(STAR_FIELD);
+    Multimap<Account.Id, String> stars = ArrayListMultimap.create();
+    for (IndexableField r : star) {
+      StarredChangesUtil.StarField starField =
+          StarredChangesUtil.StarField.parse(r.stringValue());
+      if (starField != null) {
+        stars.put(starField.accountId(), starField.label());
+      }
+    }
+    cd.setStars(stars);
+  }
+
  private static <T> List<T> decodeProtos(Document doc, String fieldName,
      ProtobufCodec<T> codec) {
    BytesRef[] bytesRefs = doc.getBinaryValues(fieldName);
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/RebuildNoteDb.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/RebuildNoteDb.java
@@ -28,6 +28,7 @@ import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.ListeningExecutorService;
 import com.google.common.util.concurrent.MoreExecutors;
+import com.google.gerrit.extensions.config.FactoryModule;
 import com.google.gerrit.extensions.events.GitReferenceUpdatedListener;
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.lifecycle.LifecycleManager;
@@ -38,6 +39,7 @@ import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.GitRepositoryManager;
@@ -50,7 +52,6 @@ import com.google.gerrit.server.notedb.NotesMigration;
 import com.google.gerrit.server.schema.DisabledChangesReviewDbWrapper;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.SchemaFactory;
-import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
 import com.google.inject.Injector;

@@ -206,7 +207,7 @@ public class RebuildNoteDb extends SiteProgram {
  }

  private Injector createSysInjector() {
-    return dbInjector.createChildInjector(new AbstractModule() {
+    return dbInjector.createChildInjector(new FactoryModule() {
      @Override
      public void configure() {
        install(dbInjector.getInstance(BatchProgramModule.class));
@@ -214,6 +215,7 @@ public class RebuildNoteDb extends SiteProgram {
        DynamicSet.bind(binder(), GitReferenceUpdatedListener.class).to(
            ReindexAfterUpdate.class);
        install(new DummyIndexModule());
+        factory(ChangeResource.Factory.class);
      }
    });
  }
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
@@ -18,11 +18,13 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.gerrit.server.schema.DataSourceProvider.Context.MULTI_USER;

 import com.google.gerrit.common.Die;
+import com.google.gerrit.extensions.config.FactoryModule;
 import com.google.gerrit.lifecycle.LifecycleManager;
 import com.google.gerrit.lucene.LuceneIndexModule;
 import com.google.gerrit.pgm.util.BatchProgramModule;
 import com.google.gerrit.pgm.util.SiteProgram;
 import com.google.gerrit.pgm.util.ThreadLimiter;
+import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.ScanningChangeCacheImpl;
 import com.google.gerrit.server.index.Index;
@@ -129,6 +131,12 @@ public class Reindex extends SiteProgram {
    // will have just deleted the old (possibly corrupt) index.
    modules.add(ScanningChangeCacheImpl.module());
    modules.add(dbInjector.getInstance(BatchProgramModule.class));
+    modules.add(new FactoryModule() {
+      @Override
+      protected void configure() {
+        factory(ChangeResource.Factory.class);
+      }
+    });

    return dbInjector.createChildInjector(modules);
  }
--- a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/server/ReviewDbUtil.java
+++ b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/server/ReviewDbUtil.java
@@ -21,7 +21,7 @@ import com.google.gwtorm.client.IntKey;

 /** Static utilities for ReviewDb types. */
 public class ReviewDbUtil {
-  private static final Function<IntKey<?>, Integer> INT_KEY_FUNCTION =
+  public static final Function<IntKey<?>, Integer> INT_KEY_FUNCTION =
      new Function<IntKey<?>, Integer>() {
        @Override
        public Integer apply(IntKey<?> in) {
--- a/gerrit-reviewdb/src/test/java/com/google/gerrit/reviewdb/client/ChangeTest.java
+++ b/gerrit-reviewdb/src/test/java/com/google/gerrit/reviewdb/client/ChangeTest.java
@@ -15,6 +15,8 @@
 package com.google.gerrit.reviewdb.client;

 import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;

 import org.junit.Test;

@@ -79,6 +81,27 @@ public class ChangeTest {
        .isEqualTo("refs/changes/34/1234/");
  }

+  @Test
+  public void parseRefNameParts() {
+    assertRefPart(1, "01/1");
+
+    assertNotRefPart(null);
+    assertNotRefPart("");
+
+    // This method assumes that the common prefix "refs/changes/" was removed.
+    assertNotRefPart("refs/changes/01/1");
+
+    // Invalid characters.
+    assertNotRefPart("01a/1");
+    assertNotRefPart("01/a1");
+
+    // Mismatched shard.
+    assertNotRefPart("01/23");
+
+    // Shard too short.
+    assertNotRefPart("1/1");
+  }
+
  private static void assertRef(int changeId, String refName) {
    assertThat(Change.Id.fromRef(refName)).isEqualTo(new Change.Id(changeId));
  }
@@ -86,4 +109,12 @@ public class ChangeTest {
  private static void assertNotRef(String refName) {
    assertThat(Change.Id.fromRef(refName)).isNull();
  }
+
+  private static void assertRefPart(int changeId, String refName) {
+    assertEquals(new Change.Id(changeId), Change.Id.fromRefPart(refName));
+  }
+
+  private static void assertNotRefPart(String refName) {
+    assertNull(Change.Id.fromRefPart(refName));
+  }
 }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/CurrentUser.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/CurrentUser.java
@@ -79,6 +79,7 @@ public abstract class CurrentUser {
  public abstract GroupMembership getEffectiveGroups();

  /** Set of changes starred by this user. */
+  @Deprecated
  public abstract Set<Change.Id> getStarredChanges();

  /** Filters selecting changes the user wants to monitor. */
--- a/gerrit-server/src/main/java/com/google/gerrit/server/IdentifiedUser.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/IdentifiedUser.java
@@ -348,6 +348,7 @@ public class IdentifiedUser extends CurrentUser {
    return starredChanges;
  }

+  @Deprecated
  public void clearStarredChanges() {
    // Async query may have started before an update that the caller expects
    // to see the results of, so we can't trust it.
@@ -355,13 +356,14 @@ public class IdentifiedUser extends CurrentUser {
    starredChanges = null;
  }

-  @SuppressWarnings("deprecation")
+  @Deprecated
  public void asyncStarredChanges() {
    if (starredChanges == null && starredChangesUtil != null) {
      starredQuery = starredChangesUtil.queryFromIndex(accountId);
    }
  }

+  @Deprecated
  public void abortStarredChanges() {
    if (starredQuery != null) {
      try {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java
@@ -16,14 +16,18 @@ package com.google.gerrit.server;

 import static java.nio.charset.StandardCharsets.UTF_8;

+import com.google.auto.value.AutoValue;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Function;
 import com.google.common.base.Joiner;
+import com.google.common.base.Predicate;
 import com.google.common.base.Splitter;
 import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Iterables;
+import com.google.common.primitives.Ints;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
@@ -61,18 +65,66 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import java.io.IOException;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;

@Singleton
 public class StarredChangesUtil {
+  @AutoValue
+  public abstract static class StarField {
+    private static final String SEPARATOR = ":";
+
+    public static StarField parse(String s) {
+      int p = s.indexOf(SEPARATOR);
+      if (p >= 0) {
+        Integer id = Ints.tryParse(s.substring(0, p));
+        if (id == null) {
+          return null;
+        }
+        Account.Id accountId = new Account.Id(id);
+        String label = s.substring(p + 1);
+        return create(accountId, label);
+      }
+      return null;
+    }
+
+    public static StarField create(Account.Id accountId, String label) {
+      return new AutoValue_StarredChangesUtil_StarField(accountId, label);
+    }
+
+    public abstract Account.Id accountId();
+    public abstract String label();
+
+    @Override
+    public String toString() {
+      return accountId() + SEPARATOR + label();
+    }
+  }
+
+  public static class IllegalLabelException extends IllegalArgumentException {
+    private static final long serialVersionUID = 1L;
+
+    static IllegalLabelException invalidLabels(Set<String> invalidLabels) {
+      return new IllegalLabelException(
+          String.format("invalid labels: %s",
+              Joiner.on(", ").join(invalidLabels)));
+    }
+
+    IllegalLabelException(String message) {
+      super(message);
+    }
+  }
+
  private static final Logger log =
      LoggerFactory.getLogger(StarredChangesUtil.class);

-  private static final String DEFAULT_LABEL = "star";
+  public static final String DEFAULT_LABEL = "star";
  public static final ImmutableSortedSet<String> DEFAULT_LABELS =
      ImmutableSortedSet.of(DEFAULT_LABEL);

@@ -98,53 +150,44 @@ public class StarredChangesUtil {
    this.queryProvider = queryProvider;
  }

-  public void star(Account.Id accountId, Project.NameKey project,
+  public ImmutableSortedSet<String> getLabels(Account.Id accountId,
      Change.Id changeId) throws OrmException {
    try (Repository repo = repoManager.openRepository(allUsers)) {
-      String refName = RefNames.refsStarredChanges(changeId, accountId);
-      ObjectId oldObjectId = getObjectId(repo, refName);
-      SortedSet<String> labels = readLabels(repo, oldObjectId);
-      labels.add(DEFAULT_LABEL);
-      updateLabels(repo, refName, oldObjectId, labels);
-      indexer.index(dbProvider.get(), project, changeId);
+      return ImmutableSortedSet.copyOf(
+          readLabels(repo, RefNames.refsStarredChanges(changeId, accountId)));
    } catch (IOException e) {
      throw new OrmException(
-          String.format("Star change %d for account %d failed",
+          String.format("Reading stars from change %d for account %d failed",
              changeId.get(), accountId.get()), e);
    }
  }

-  public void unstar(Account.Id accountId, Project.NameKey project,
-      Change.Id changeId) throws OrmException {
-    try (Repository repo = repoManager.openRepository(allUsers);
-        RevWalk rw = new RevWalk(repo)) {
-      RefUpdate u = repo.updateRef(
-          RefNames.refsStarredChanges(changeId, accountId));
-      u.setForceUpdate(true);
-      u.setRefLogIdent(serverIdent);
-      u.setRefLogMessage("Unstar change " + changeId.get(), true);
-      RefUpdate.Result result = u.delete();
-      switch (result) {
-        case FORCED:
-          indexer.index(dbProvider.get(), project, changeId);
-          return;
-        case FAST_FORWARD:
-        case IO_FAILURE:
-        case LOCK_FAILURE:
-        case NEW:
-        case NOT_ATTEMPTED:
-        case NO_CHANGE:
-        case REJECTED:
-        case REJECTED_CURRENT_BRANCH:
-        case RENAMED:
-        default:
-          throw new OrmException(
-              String.format("Unstar change %d for account %d failed: %s",
-                  changeId.get(), accountId.get(), result.name()));
+  public ImmutableSortedSet<String> star(Account.Id accountId,
+      Project.NameKey project, Change.Id changeId, Set<String> labelsToAdd,
+      Set<String> labelsToRemove) throws OrmException {
+    try (Repository repo = repoManager.openRepository(allUsers)) {
+      String refName = RefNames.refsStarredChanges(changeId, accountId);
+      ObjectId oldObjectId = getObjectId(repo, refName);
+
+      SortedSet<String> labels = readLabels(repo, oldObjectId);
+      if (labelsToAdd != null) {
+        labels.addAll(labelsToAdd);
      }
+      if (labelsToRemove != null) {
+        labels.removeAll(labelsToRemove);
+      }
+
+      if (labels.isEmpty()) {
+        deleteRef(repo, refName, oldObjectId);
+      } else {
+        updateLabels(repo, refName, oldObjectId, labels);
+      }
+
+      indexer.index(dbProvider.get(), project, changeId);
+      return ImmutableSortedSet.copyOf(labels);
    } catch (IOException e) {
      throw new OrmException(
-          String.format("Unstar change %d for account %d failed",
+          String.format("Star change %d for account %d failed",
              changeId.get(), accountId.get()), e);
    }
  }
@@ -157,7 +200,7 @@ public class StarredChangesUtil {
      batchUpdate.setAllowNonFastForwards(true);
      batchUpdate.setRefLogIdent(serverIdent);
      batchUpdate.setRefLogMessage("Unstar change " + changeId.get(), true);
-      for (Account.Id accountId : byChangeFromIndex(changeId)) {
+      for (Account.Id accountId : byChangeFromIndex(changeId).keySet()) {
        String refName = RefNames.refsStarredChanges(changeId, accountId);
        Ref ref = repo.getRefDatabase().getRef(refName);
        batchUpdate.addCommand(new ReceiveCommand(ref.getObjectId(),
@@ -178,29 +221,84 @@ public class StarredChangesUtil {
    }
  }

-  public Set<Account.Id> byChange(Change.Id changeId)
+  public ImmutableMultimap<Account.Id, String> byChange(Change.Id changeId)
      throws OrmException {
-    return FluentIterable
-        .from(getRefNames(RefNames.refsStarredChangesPrefix(changeId)))
-        .transform(new Function<String, Account.Id>() {
-          @Override
-          public Account.Id apply(String refPart) {
-            return Account.Id.parse(refPart);
-          }
-        }).toSet();
+    try (Repository repo = repoManager.openRepository(allUsers)) {
+      ImmutableMultimap.Builder<Account.Id, String> builder =
+          new ImmutableMultimap.Builder<>();
+      for (String refPart : getRefNames(repo,
+          RefNames.refsStarredChangesPrefix(changeId))) {
+        Integer id = Ints.tryParse(refPart);
+        if (id == null) {
+          continue;
+        }
+        Account.Id accountId = new Account.Id(id);
+        builder.putAll(accountId,
+            readLabels(repo, RefNames.refsStarredChanges(changeId, accountId)));
+      }
+      return builder.build();
+    } catch (IOException e) {
+      throw new OrmException(String.format(
+          "Get accounts that starred change %d failed", changeId.get()), e);
+    }
  }

-  public Set<Account.Id> byChangeFromIndex(Change.Id changeId)
-      throws OrmException, NoSuchChangeException {
+  public Set<Account.Id> byChange(final Change.Id changeId,
+      final String label) throws OrmException {
+    try (final Repository repo = repoManager.openRepository(allUsers)) {
+      return FluentIterable
+          .from(getRefNames(repo, RefNames.refsStarredChangesPrefix(changeId)))
+          .transform(new Function<String, Account.Id>() {
+            @Override
+            public Account.Id apply(String refPart) {
+              return Account.Id.parse(refPart);
+            }
+          })
+          .filter(new Predicate<Account.Id>() {
+            @Override
+            public boolean apply(Account.Id accountId) {
+              try {
+                return readLabels(repo,
+                    RefNames.refsStarredChanges(changeId, accountId))
+                        .contains(label);
+              } catch (IOException e) {
+                log.error(String.format(
+                    "Cannot query stars by account %d on change %d",
+                    accountId.get(), changeId.get()), e);
+                return false;
+              }
+            }
+          }).toSet();
+    } catch (IOException e) {
+      throw new OrmException(
+          String.format("Get accounts that starred change %d failed",
+              changeId.get()), e);
+    }
+  }
+
+  public ImmutableMultimap<Account.Id, String> byChangeFromIndex(
+      Change.Id changeId) throws OrmException, NoSuchChangeException {
    Set<String> fields = ImmutableSet.of(
        ChangeField.ID.getName(),
-        ChangeField.STARREDBY.getName());
+        ChangeField.STAR.getName());
    List<ChangeData> changeData = queryProvider.get().setRequestedFields(fields)
        .byLegacyChangeId(changeId);
    if (changeData.size() != 1) {
      throw new NoSuchChangeException(changeId);
    }
-    return changeData.get(0).starredBy();
+    return changeData.get(0).stars();
+  }
+
+  public Set<Account.Id> byChangeFromIndex(Change.Id changeId, String label)
+      throws OrmException, NoSuchChangeException {
+    Set<Account.Id> accounts = new HashSet<>();
+    for (Map.Entry<Account.Id, Collection<String>> e : byChangeFromIndex(
+        changeId).asMap().entrySet()) {
+      if (e.getValue().contains(label)) {
+        accounts.add(e.getKey());
+      }
+    }
+    return accounts;
  }

  @Deprecated
@@ -226,12 +324,21 @@ public class StarredChangesUtil {
    }
  }

-  private Set<String> getRefNames(String prefix) throws OrmException {
+  private static Set<String> getRefNames(Repository repo, String prefix)
+      throws IOException {
+    RefDatabase refDb = repo.getRefDatabase();
+    return refDb.getRefs(prefix).keySet();
+  }
+
+  public ObjectId getObjectId(Account.Id accountId, Change.Id changeId) {
    try (Repository repo = repoManager.openRepository(allUsers)) {
-      RefDatabase refDb = repo.getRefDatabase();
-      return refDb.getRefs(prefix).keySet();
+      return getObjectId(repo,
+          RefNames.refsStarredChanges(changeId, accountId));
    } catch (IOException e) {
-      throw new OrmException(e);
+      log.error(String.format(
+          "Getting star object ID for account %d on change %d failed",
+          accountId.get(), changeId.get()), e);
+      return ObjectId.zeroId();
    }
  }

@@ -241,6 +348,11 @@ public class StarredChangesUtil {
    return ref != null ? ref.getObjectId() : ObjectId.zeroId();
  }

+  private static SortedSet<String> readLabels(Repository repo, String refName)
+      throws IOException {
+    return readLabels(repo, getObjectId(repo, refName));
+  }
+
  private static TreeSet<String> readLabels(Repository repo, ObjectId id)
      throws IOException {
    if (ObjectId.zeroId().equals(id)) {
@@ -259,13 +371,7 @@ public class StarredChangesUtil {

  public static ObjectId writeLabels(Repository repo, SortedSet<String> labels)
      throws IOException {
-    SortedSet<String> invalidLabels = validateLabels(labels);
-    if (!invalidLabels.isEmpty()) {
-      throw new IllegalArgumentException(
-          String.format("Invalid star labels: %s",
-              Joiner.on(", ").join(labels)));
-    }
-
+    validateLabels(labels);
    try (ObjectInserter oi = repo.newObjectInserter()) {
      ObjectId id = oi.insert(Constants.OBJ_BLOB,
          Joiner.on("\n").join(labels).getBytes(UTF_8));
@@ -274,9 +380,9 @@ public class StarredChangesUtil {
    }
  }

-  private static SortedSet<String> validateLabels(Set<String> labels) {
+  private static void validateLabels(Set<String> labels) {
    if (labels == null) {
-      return ImmutableSortedSet.of();
+      return;
    }

    SortedSet<String> invalidLabels = new TreeSet<>();
@@ -285,7 +391,9 @@ public class StarredChangesUtil {
        invalidLabels.add(label);
      }
    }
-    return invalidLabels;
+    if (!invalidLabels.isEmpty()) {
+      throw IllegalLabelException.invalidLabels(invalidLabels);
+    }
  }

  private void updateLabels(Repository repo, String refName,
@@ -317,4 +425,29 @@ public class StarredChangesUtil {
      }
    }
  }
+
+  private void deleteRef(Repository repo, String refName, ObjectId oldObjectId)
+      throws IOException, OrmException {
+    RefUpdate u = repo.updateRef(refName);
+    u.setForceUpdate(true);
+    u.setExpectedOldObjectId(oldObjectId);
+    u.setRefLogIdent(serverIdent);
+    u.setRefLogMessage("Unstar change", true);
+    RefUpdate.Result result = u.delete();
+    switch (result) {
+      case FORCED:
+        return;
+      case NEW:
+      case NO_CHANGE:
+      case FAST_FORWARD:
+      case IO_FAILURE:
+      case LOCK_FAILURE:
+      case NOT_ATTEMPTED:
+      case REJECTED:
+      case REJECTED_CURRENT_BRANCH:
+      case RENAMED:
+        throw new OrmException(String.format("Delete star ref %s failed: %s",
+            refName, result.name()));
+    }
+  }
 }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResource.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResource.java
@@ -22,6 +22,8 @@ import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.inject.TypeLiteral;

+import java.util.Set;
+
 public class AccountResource implements RestResource {
  public static final TypeLiteral<RestView<AccountResource>> ACCOUNT_KIND =
      new TypeLiteral<RestView<AccountResource>>() {};
@@ -108,4 +110,32 @@ public class AccountResource implements RestResource {
      return change.getChange();
    }
  }
+
+  public static class Star implements RestResource {
+    public static final TypeLiteral<RestView<Star>> STAR_KIND =
+        new TypeLiteral<RestView<Star>>() {};
+
+    private final IdentifiedUser user;
+    private final ChangeResource change;
+    private final Set<String> labels;
+
+    public Star(IdentifiedUser user, ChangeResource change,
+        Set<String> labels) {
+      this.user = user;
+      this.change = change;
+      this.labels = labels;
+    }
+
+    public IdentifiedUser getUser() {
+      return user;
+    }
+
+    public Change getChange() {
+      return change.getChange();
+    }
+
+    public Set<String> getLabels() {
+      return labels;
+    }
+  }
 }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/Module.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/Module.java
@@ -19,6 +19,7 @@ import static com.google.gerrit.server.account.AccountResource.CAPABILITY_KIND;
 import static com.google.gerrit.server.account.AccountResource.EMAIL_KIND;
 import static com.google.gerrit.server.account.AccountResource.SSH_KEY_KIND;
 import static com.google.gerrit.server.account.AccountResource.STARRED_CHANGE_KIND;
+import static com.google.gerrit.server.account.AccountResource.Star.STAR_KIND;

 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.RestApiModule;
@@ -34,6 +35,7 @@ public class Module extends RestApiModule {
    DynamicMap.mapOf(binder(), EMAIL_KIND);
    DynamicMap.mapOf(binder(), SSH_KEY_KIND);
    DynamicMap.mapOf(binder(), STARRED_CHANGE_KIND);
+    DynamicMap.mapOf(binder(), STAR_KIND);

    put(ACCOUNT_KIND).to(PutAccount.class);
    get(ACCOUNT_KIND).to(GetAccount.class);
@@ -83,6 +85,10 @@ public class Module extends RestApiModule {
    delete(STARRED_CHANGE_KIND).to(StarredChanges.Delete.class);
    bind(StarredChanges.Create.class);

+    child(ACCOUNT_KIND, "stars.changes").to(Stars.class);
+    get(STAR_KIND).to(Stars.Get.class);
+    post(STAR_KIND).to(Stars.Post.class);
+
    factory(CreateAccount.Factory.class);
    factory(CreateEmail.Factory.class);
  }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java
@@ -53,31 +53,29 @@ public class StarredChanges implements
  private final ChangesCollection changes;
  private final DynamicMap<RestView<AccountResource.StarredChange>> views;
  private final Provider<Create> createProvider;
+  private final StarredChangesUtil starredChangesUtil;

  @Inject
  StarredChanges(ChangesCollection changes,
      DynamicMap<RestView<AccountResource.StarredChange>> views,
-      Provider<Create> createProvider) {
+      Provider<Create> createProvider,
+      StarredChangesUtil starredChangesUtil) {
    this.changes = changes;
    this.views = views;
    this.createProvider = createProvider;
+    this.starredChangesUtil = starredChangesUtil;
  }

  @Override
  public AccountResource.StarredChange parse(AccountResource parent, IdString id)
      throws ResourceNotFoundException, OrmException {
    IdentifiedUser user = parent.getUser();
-    try {
-      user.asyncStarredChanges();
-
-      ChangeResource change = changes.parse(TopLevelResource.INSTANCE, id);
-      if (user.getStarredChanges().contains(change.getId())) {
-        return new AccountResource.StarredChange(user, change);
-      }
-      throw new ResourceNotFoundException(id);
-    } finally {
-      user.abortStarredChanges();
+    ChangeResource change = changes.parse(TopLevelResource.INSTANCE, id);
+    if (starredChangesUtil.getLabels(user.getAccountId(), change.getId())
+        .contains(StarredChangesUtil.DEFAULT_LABEL)) {
+      return new AccountResource.StarredChange(user, change);
    }
+    throw new ResourceNotFoundException(id);
  }

  @Override
@@ -138,7 +136,7 @@ public class StarredChanges implements
      }
      try {
        starredChangesUtil.star(self.get().getAccountId(), change.getProject(),
-            change.getId());
+            change.getId(), StarredChangesUtil.DEFAULT_LABELS, null);
      } catch (OrmDuplicateKeyException e) {
        return Response.none();
      }
@@ -184,8 +182,9 @@ public class StarredChanges implements
      if (self.get() != rsrc.getUser()) {
        throw new AuthException("not allowed remove starred change");
      }
-      starredChangesUtil.unstar(self.get().getAccountId(),
-          rsrc.getChange().getProject(), rsrc.getChange().getId());
+      starredChangesUtil.star(self.get().getAccountId(),
+          rsrc.getChange().getProject(), rsrc.getChange().getId(), null,
+          StarredChangesUtil.DEFAULT_LABELS);
      return Response.none();
    }
  }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/Stars.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/Stars.java
@@ -0,0 +1,167 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.account;
+
+import com.google.gerrit.extensions.api.changes.StarsInput;
+import com.google.gerrit.extensions.common.ChangeInfo;
+import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.extensions.restapi.TopLevelResource;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
+import com.google.gerrit.server.account.AccountResource.Star;
+import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.change.ChangesCollection;
+import com.google.gerrit.server.query.change.QueryChanges;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.SortedSet;
+
+@Singleton
+public class Stars implements
+    ChildCollection<AccountResource, AccountResource.Star> {
+
+  private final ChangesCollection changes;
+  private final ListStarredChanges listStarredChanges;
+  private final StarredChangesUtil starredChangesUtil;
+  private final DynamicMap<RestView<AccountResource.Star>> views;
+
+  @Inject
+  Stars(ChangesCollection changes,
+      ListStarredChanges listStarredChanges,
+      StarredChangesUtil starredChangesUtil,
+      DynamicMap<RestView<AccountResource.Star>> views) {
+    this.changes = changes;
+    this.listStarredChanges = listStarredChanges;
+    this.starredChangesUtil = starredChangesUtil;
+    this.views = views;
+  }
+
+  @Override
+  public Star parse(AccountResource parent, IdString id)
+      throws ResourceNotFoundException, OrmException {
+    IdentifiedUser user = parent.getUser();
+    ChangeResource change = changes.parse(TopLevelResource.INSTANCE, id);
+    Set<String> labels =
+        starredChangesUtil.getLabels(user.getAccountId(), change.getId());
+    return new AccountResource.Star(user, change, labels);
+  }
+
+  @Override
+  public DynamicMap<RestView<Star>> views() {
+    return views;
+  }
+
+  @Override
+  public ListStarredChanges list() {
+    return listStarredChanges;
+  }
+
+  @Singleton
+  public static class ListStarredChanges
+      implements RestReadView<AccountResource> {
+    private final Provider<CurrentUser> self;
+    private final ChangesCollection changes;
+
+    @Inject
+    ListStarredChanges(Provider<CurrentUser> self,
+        ChangesCollection changes) {
+      this.self = self;
+      this.changes = changes;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public List<ChangeInfo> apply(AccountResource rsrc)
+        throws BadRequestException, AuthException, OrmException {
+      if (self.get() != rsrc.getUser()) {
+        throw new AuthException(
+            "not allowed to list stars of another account");
+      }
+      QueryChanges query = changes.list();
+      query.addQuery("has:stars");
+      return (List<ChangeInfo>) query.apply(TopLevelResource.INSTANCE);
+    }
+  }
+
+  @Singleton
+  public static class Get implements
+      RestReadView<AccountResource.Star> {
+    private final Provider<CurrentUser> self;
+    private final StarredChangesUtil starredChangesUtil;
+
+    @Inject
+    Get(Provider<CurrentUser> self,
+        StarredChangesUtil starredChangesUtil) {
+      this.self = self;
+      this.starredChangesUtil = starredChangesUtil;
+    }
+
+    @Override
+    public SortedSet<String> apply(AccountResource.Star rsrc)
+        throws AuthException, OrmException {
+      if (self.get() != rsrc.getUser()) {
+        throw new AuthException("not allowed to get stars of another account");
+      }
+      return starredChangesUtil.getLabels(self.get().getAccountId(),
+          rsrc.getChange().getId());
+    }
+  }
+
+  @Singleton
+  public static class Post implements
+      RestModifyView<AccountResource.Star, StarsInput> {
+    private final Provider<CurrentUser> self;
+    private final StarredChangesUtil starredChangesUtil;
+
+    @Inject
+    Post(Provider<CurrentUser> self,
+        StarredChangesUtil starredChangesUtil) {
+      this.self = self;
+      this.starredChangesUtil = starredChangesUtil;
+    }
+
+    @Override
+    public Collection<String> apply(AccountResource.Star rsrc, StarsInput in)
+        throws AuthException, BadRequestException, OrmException {
+      if (self.get() != rsrc.getUser()) {
+        throw new AuthException(
+            "not allowed to update stars of another account");
+      }
+      try {
+        return starredChangesUtil.star(self.get().getAccountId(),
+            rsrc.getChange().getProject(), rsrc.getChange().getId(), in.add,
+            in.remove);
+      } catch (IllegalLabelException e) {
+        throw new BadRequestException(e.getMessage());
+      }
+    }
+  }
+}
--- a/gerrit-server/src/main/java/com/google/gerrit/server/api/accounts/AccountApiImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/api/accounts/AccountApiImpl.java
@@ -19,11 +19,13 @@ import com.google.gerrit.common.errors.EmailException;
 import com.google.gerrit.extensions.api.accounts.AccountApi;
 import com.google.gerrit.extensions.api.accounts.EmailInput;
 import com.google.gerrit.extensions.api.accounts.GpgKeyApi;
+import com.google.gerrit.extensions.api.changes.StarsInput;
 import com.google.gerrit.extensions.client.DiffPreferencesInfo;
 import com.google.gerrit.extensions.client.EditPreferencesInfo;
 import com.google.gerrit.extensions.client.GeneralPreferencesInfo;
 import com.google.gerrit.extensions.client.ProjectWatchInfo;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.GpgKeyInfo;
 import com.google.gerrit.extensions.common.SshKeyInfo;
 import com.google.gerrit.extensions.restapi.IdString;
@@ -48,6 +50,7 @@ import com.google.gerrit.server.account.SetEditPreferences;
 import com.google.gerrit.server.account.SetPreferences;
 import com.google.gerrit.server.account.SshKeys;
 import com.google.gerrit.server.account.StarredChanges;
+import com.google.gerrit.server.account.Stars;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.change.ChangesCollection;
 import com.google.gwtorm.server.OrmException;
@@ -59,6 +62,7 @@ import org.eclipse.jgit.errors.ConfigInvalidException;
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;

 public class AccountApiImpl implements AccountApi {
  interface Factory {
@@ -80,6 +84,9 @@ public class AccountApiImpl implements AccountApi {
  private final DeleteWatchedProjects deleteWatchedProjects;
  private final StarredChanges.Create starredChangesCreate;
  private final StarredChanges.Delete starredChangesDelete;
+  private final Stars stars;
+  private final Stars.Get starsGet;
+  private final Stars.Post starsPost;
  private final CreateEmail.Factory createEmailFactory;
  private final GpgApiAdapter gpgApiAdapter;
  private final GetSshKeys getSshKeys;
@@ -102,6 +109,9 @@ public class AccountApiImpl implements AccountApi {
      DeleteWatchedProjects deleteWatchedProjects,
      StarredChanges.Create starredChangesCreate,
      StarredChanges.Delete starredChangesDelete,
+      Stars stars,
+      Stars.Get starsGet,
+      Stars.Post starsPost,
      CreateEmail.Factory createEmailFactory,
      GpgApiAdapter gpgApiAdapter,
      GetSshKeys getSshKeys,
@@ -124,6 +134,9 @@ public class AccountApiImpl implements AccountApi {
    this.deleteWatchedProjects = deleteWatchedProjects;
    this.starredChangesCreate = starredChangesCreate;
    this.starredChangesDelete = starredChangesDelete;
+    this.stars = stars;
+    this.starsGet = starsGet;
+    this.starsPost = starsPost;
    this.createEmailFactory = createEmailFactory;
    this.getSshKeys = getSshKeys;
    this.addSshKey = addSshKey;
@@ -234,11 +247,11 @@ public class AccountApiImpl implements AccountApi {
  }

  @Override
-  public void starChange(String id) throws RestApiException {
+  public void starChange(String changeId) throws RestApiException {
    try {
      ChangeResource rsrc = changes.parse(
        TopLevelResource.INSTANCE,
-        IdString.fromUrl(id));
+        IdString.fromUrl(changeId));
      starredChangesCreate.setChange(rsrc);
      starredChangesCreate.apply(account, new StarredChanges.EmptyInput());
    } catch (OrmException | IOException e) {
@@ -247,10 +260,10 @@ public class AccountApiImpl implements AccountApi {
  }

  @Override
-  public void unstarChange(String id) throws RestApiException {
+  public void unstarChange(String changeId) throws RestApiException {
    try {
      ChangeResource rsrc =
-          changes.parse(TopLevelResource.INSTANCE, IdString.fromUrl(id));
+          changes.parse(TopLevelResource.INSTANCE, IdString.fromUrl(changeId));
      AccountResource.StarredChange starredChange =
          new AccountResource.StarredChange(account.getUser(), rsrc);
      starredChangesDelete.apply(starredChange,
@@ -260,6 +273,38 @@ public class AccountApiImpl implements AccountApi {
    }
  }

+  @Override
+  public void setStars(String changeId, StarsInput input)
+      throws RestApiException {
+    try {
+      AccountResource.Star rsrc =
+          stars.parse(account, IdString.fromUrl(changeId));
+      starsPost.apply(rsrc, input);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot post stars", e);
+    }
+  }
+
+  @Override
+  public SortedSet<String> getStars(String changeId) throws RestApiException {
+    try {
+      AccountResource.Star rsrc =
+          stars.parse(account, IdString.fromUrl(changeId));
+      return starsGet.apply(rsrc);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot get stars", e);
+    }
+  }
+
+  @Override
+  public List<ChangeInfo> getStarredChanges() throws RestApiException {
+    try {
+      return stars.list().apply(account);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot get starred changes", e);
+    }
+  }
+
  @Override
  public void addEmail(EmailInput input) throws RestApiException {
    AccountResource.Email rsrc =
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ActionJson.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ActionJson.java
@@ -35,13 +35,16 @@ import java.util.Map;
@Singleton
 public class ActionJson {
  private final Revisions revisions;
+  private final ChangeResource.Factory changeResourceFactory;
  private final DynamicMap<RestView<ChangeResource>> changeViews;

  @Inject
  ActionJson(
      Revisions revisions,
+      ChangeResource.Factory changeResourceFactory,
      DynamicMap<RestView<ChangeResource>> changeViews) {
    this.revisions = revisions;
+    this.changeResourceFactory = changeResourceFactory;
    this.changeViews = changeViews;
  }

@@ -69,7 +72,7 @@ public class ActionJson {
    Provider<CurrentUser> userProvider = Providers.of(ctl.getUser());
    for (UiAction.Description d : UiActions.from(
        changeViews,
-        new ChangeResource(ctl),
+        changeResourceFactory.create(ctl),
        userProvider)) {
      out.put(d.getId(), new ActionInfo(d));
    }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java
@@ -89,6 +89,7 @@ import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.GpgException;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.WebLinks;
 import com.google.gerrit.server.account.AccountLoader;
 import com.google.gerrit.server.api.accounts.AccountInfoComparator;
@@ -161,6 +162,7 @@ public class ChangeJson {
  private final ActionJson actionJson;
  private final GpgApiAdapter gpgApi;
  private final ChangeNotes.Factory notesFactory;
+  private final ChangeResource.Factory changeResourceFactory;

  private AccountLoader accountLoader;
  private Map<Change.Id, List<SubmitRecord>> submitRecords;
@@ -187,6 +189,7 @@ public class ChangeJson {
      ActionJson actionJson,
      GpgApiAdapter gpgApi,
      ChangeNotes.Factory notesFactory,
+      ChangeResource.Factory changeResourceFactory,
      @Assisted Set<ListChangesOption> options) {
    this.db = db;
    this.labelNormalizer = ln;
@@ -207,6 +210,7 @@ public class ChangeJson {
    this.actionJson = actionJson;
    this.gpgApi = gpgApi;
    this.notesFactory = notesFactory;
+    this.changeResourceFactory = changeResourceFactory;
    this.options = options.isEmpty()
        ? EnumSet.noneOf(ListChangesOption.class)
        : EnumSet.copyOf(options);
@@ -956,7 +960,7 @@ public class ChangeJson {
        && userProvider.get().isIdentifiedUser()) {

      actionJson.addRevisionActions(out,
-          new RevisionResource(new ChangeResource(ctl), in));
+          new RevisionResource(changeResourceFactory.create(ctl), in));
    }

    if (has(PUSH_CERTIFICATES)) {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeResource.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeResource.java
@@ -14,6 +14,8 @@

 package com.google.gerrit.server.change;

+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.google.common.base.MoreObjects;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;
@@ -25,11 +27,14 @@ import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.TypeLiteral;
+import com.google.inject.assistedinject.Assisted;
+import com.google.inject.assistedinject.AssistedInject;

 import org.eclipse.jgit.lib.ObjectId;

@@ -45,9 +50,17 @@ public class ChangeResource implements RestResource, HasETag {
  public static final TypeLiteral<RestView<ChangeResource>> CHANGE_KIND =
      new TypeLiteral<RestView<ChangeResource>>() {};

+  public interface Factory {
+    ChangeResource create(ChangeControl ctl);
+  }
+
+  private final StarredChangesUtil starredChangesUtil;
  private final ChangeControl control;

-  public ChangeResource(ChangeControl control) {
+  @AssistedInject
+  ChangeResource(StarredChangesUtil starredChangesUtil,
+      @Assisted ChangeControl control) {
+    this.starredChangesUtil = starredChangesUtil;
    this.control = control;
  }

@@ -108,8 +121,10 @@ public class ChangeResource implements RestResource, HasETag {
  @Override
  public String getETag() {
    CurrentUser user = control.getUser();
-    Hasher h = Hashing.md5().newHasher()
-        .putBoolean(user.getStarredChanges().contains(getId()));
+    Hasher h = Hashing.md5().newHasher();
+    h.putString(
+        starredChangesUtil.getObjectId(user.getAccountId(), getId()).name(),
+        UTF_8);
    prepareETag(h, user);
    return h.hash().toString();
  }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangesCollection.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangesCollection.java
@@ -45,6 +45,7 @@ public class ChangesCollection implements
  private final DynamicMap<RestView<ChangeResource>> views;
  private final ChangeFinder changeFinder;
  private final CreateChange createChange;
+  private final ChangeResource.Factory changeResourceFactory;

  @Inject
  ChangesCollection(
@@ -53,13 +54,15 @@ public class ChangesCollection implements
      Provider<QueryChanges> queryFactory,
      DynamicMap<RestView<ChangeResource>> views,
      ChangeFinder changeFinder,
-      CreateChange createChange) {
+      CreateChange createChange,
+      ChangeResource.Factory changeResourceFactory) {
    this.db = db;
    this.user = user;
    this.queryFactory = queryFactory;
    this.views = views;
    this.changeFinder = changeFinder;
    this.createChange = createChange;
+    this.changeResourceFactory = changeResourceFactory;
  }

  @Override
@@ -86,7 +89,7 @@ public class ChangesCollection implements
    if (!ctl.isVisible(db.get())) {
      throw new ResourceNotFoundException(id);
    }
-    return new ChangeResource(ctl);
+    return changeResourceFactory.create(ctl);
  }

  public ChangeResource parse(Change.Id id)
@@ -102,7 +105,7 @@ public class ChangesCollection implements
    if (!ctl.isVisible(db.get())) {
      throw new ResourceNotFoundException(toIdString(id));
    }
-    return new ChangeResource(ctl);
+    return changeResourceFactory.create(ctl);
  }

  private static IdString toIdString(Change.Id id) {
@@ -110,7 +113,7 @@ public class ChangesCollection implements
  }

  public ChangeResource parse(ChangeControl control) {
-    return new ChangeResource(control);
+    return changeResourceFactory.create(control);
  }

  @SuppressWarnings("unchecked")
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetRevisionActions.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetRevisionActions.java
@@ -42,16 +42,19 @@ public class GetRevisionActions implements ETagView<RevisionResource> {
  private final Config config;
  private final Provider<ReviewDb> dbProvider;
  private final MergeSuperSet mergeSuperSet;
+  private final ChangeResource.Factory changeResourceFactory;

  @Inject
  GetRevisionActions(
      ActionJson delegate,
      Provider<ReviewDb> dbProvider,
      MergeSuperSet mergeSuperSet,
+      ChangeResource.Factory changeResourceFactory,
      @GerritServerConfig Config config) {
    this.delegate = delegate;
    this.dbProvider = dbProvider;
    this.mergeSuperSet = mergeSuperSet;
+    this.changeResourceFactory = changeResourceFactory;
    this.config = config;
  }

@@ -71,7 +74,7 @@ public class GetRevisionActions implements ETagView<RevisionResource> {
      ChangeSet cs =
          mergeSuperSet.completeChangeSet(db, rsrc.getChange(), user);
      for (ChangeData cd : cs.changes()) {
-        new ChangeResource(cd.changeControl()).prepareETag(h, user);
+        changeResourceFactory.create(cd.changeControl()).prepareETag(h, user);
      }
    } catch (IOException | OrmException e) {
      throw new OrmRuntimeException(e);
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java
@@ -136,5 +136,6 @@ public class Module extends RestApiModule {
    factory(RebaseChangeOp.Factory.class);
    factory(ReviewerResource.Factory.class);
    factory(SetHashtagsOp.Factory.class);
+    factory(ChangeResource.Factory.class);
  }
 }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/RebaseChangeOp.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/RebaseChangeOp.java
@@ -56,6 +56,7 @@ public class RebaseChangeOp extends BatchUpdate.Op {
  private final PatchSetInserter.Factory patchSetInserterFactory;
  private final MergeUtil.Factory mergeUtilFactory;
  private final RebaseUtil rebaseUtil;
+  private final ChangeResource.Factory changeResourceFactory;

  private final ChangeControl ctl;
  private final PatchSet originalPatchSet;
@@ -77,12 +78,14 @@ public class RebaseChangeOp extends BatchUpdate.Op {
      PatchSetInserter.Factory patchSetInserterFactory,
      MergeUtil.Factory mergeUtilFactory,
      RebaseUtil rebaseUtil,
+      ChangeResource.Factory changeResourceFactory,
      @Assisted ChangeControl ctl,
      @Assisted PatchSet originalPatchSet,
      @Assisted @Nullable String baseCommitish) {
    this.patchSetInserterFactory = patchSetInserterFactory;
    this.mergeUtilFactory = mergeUtilFactory;
    this.rebaseUtil = rebaseUtil;
+    this.changeResourceFactory = changeResourceFactory;
    this.ctl = ctl;
    this.originalPatchSet = originalPatchSet;
    this.baseCommitish = baseCommitish;
@@ -138,7 +141,8 @@ public class RebaseChangeOp extends BatchUpdate.Op {
    RevId baseRevId = new RevId((baseCommitish != null) ? baseCommitish
        : ObjectId.toString(baseCommit.getId()));
    Base base = rebaseUtil.parseBase(
-        new RevisionResource(new ChangeResource(ctl), originalPatchSet),
+        new RevisionResource(
+            changeResourceFactory.create(ctl), originalPatchSet),
        baseRevId.get());

    rebasedPatchSetId = ChangeUtil.nextPatchSetId(
--- a/gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeField.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeField.java
@@ -30,6 +30,8 @@ import com.google.gerrit.reviewdb.client.ChangeMessage;
 import com.google.gerrit.reviewdb.client.PatchLineComment;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetApproval;
+import com.google.gerrit.reviewdb.server.ReviewDbUtil;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.index.FieldDef;
 import com.google.gerrit.server.index.FieldType;
 import com.google.gerrit.server.index.SchemaUtil;
@@ -51,6 +53,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;

 /**
@@ -593,6 +596,7 @@ public class ChangeField {
      };

  /** Users who have starred this change. */
+  @Deprecated
  public static final FieldDef<ChangeData, Iterable<Integer>> STARREDBY =
      new FieldDef.Repeatable<ChangeData, Integer>(
          ChangeQueryBuilder.FIELD_STARREDBY, FieldType.INTEGER, true) {
@@ -609,6 +613,38 @@ public class ChangeField {
        }
      };

+  /**
+   * Star labels on this change in the format: <account-id>:<label>
+   */
+  public static final FieldDef<ChangeData, Iterable<String>> STAR =
+      new FieldDef.Repeatable<ChangeData, String>(
+          ChangeQueryBuilder.FIELD_STAR, FieldType.EXACT, true) {
+        @Override
+        public Iterable<String> get(ChangeData input, FillArgs args)
+            throws OrmException {
+          return Iterables.transform(input.stars().entries(),
+              new Function<Map.Entry<Account.Id, String>, String>() {
+            @Override
+            public String apply(Map.Entry<Account.Id, String> e) {
+              return StarredChangesUtil.StarField.create(
+                  e.getKey(), e.getValue()).toString();
+            }
+          });
+        }
+      };
+
+  /** Users that have starred the change with any label. */
+  public static final FieldDef<ChangeData, Iterable<Integer>> STARBY =
+      new FieldDef.Repeatable<ChangeData, Integer>(
+          ChangeQueryBuilder.FIELD_STARBY, FieldType.INTEGER, false) {
+        @Override
+        public Iterable<Integer> get(ChangeData input, FillArgs args)
+            throws OrmException {
+          return Iterables.transform(input.stars().keySet(),
+              ReviewDbUtil.INT_KEY_FUNCTION);
+        }
+      };
+
  /** Opaque group identifiers for this change's patch sets. */
  public static final FieldDef<ChangeData, Iterable<String>> GROUP =
      new FieldDef.Repeatable<ChangeData, String>(
--- a/gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
@@ -67,9 +67,13 @@ public class ChangeSchemaDefinitions extends SchemaDefinitions<ChangeData> {
  @Deprecated
  static final Schema<ChangeData> V28 = schema(V27, ChangeField.STARREDBY);

+  @Deprecated
  static final Schema<ChangeData> V29 =
      schema(V28, ChangeField.HASHTAG_CASE_AWARE);

+  static final Schema<ChangeData> V30 =
+      schema(V29, ChangeField.STAR, ChangeField.STARBY);
+
  public static final String NAME = "changes";
  public static final ChangeSchemaDefinitions INSTANCE =
      new ChangeSchemaDefinitions();
--- a/gerrit-server/src/main/java/com/google/gerrit/server/mail/ChangeEmail.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/mail/ChangeEmail.java
@@ -28,6 +28,7 @@ import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetInfo;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.mail.ProjectWatch.Watchers;
 import com.google.gerrit.server.patch.PatchList;
 import com.google.gerrit.server.patch.PatchListEntry;
@@ -305,8 +306,8 @@ public abstract class ChangeEmail extends NotificationEmail {
    try {
      // BCC anyone who has starred this change.
      //
-      for (Account.Id accountId : args.starredChangesUtil
-          .byChangeFromIndex(change.getId())) {
+      for (Account.Id accountId : args.starredChangesUtil.byChangeFromIndex(
+          change.getId(), StarredChangesUtil.DEFAULT_LABEL)) {
        super.add(RecipientType.BCC, accountId);
      }
    } catch (OrmException | NoSuchChangeException err) {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -24,10 +24,12 @@ import com.google.common.base.Optional;
 import com.google.common.base.Predicate;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Multimap;
 import com.google.common.collect.SetMultimap;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.SubmitRecord;
@@ -345,7 +347,9 @@ public class ChangeData {
  private Set<Account.Id> editsByUser;
  private Set<Account.Id> reviewedBy;
  private Set<Account.Id> draftsByUser;
+  @Deprecated
  private Set<Account.Id> starredByUser;
+  private ImmutableMultimap<Account.Id, String> stars;
  private PersonIdent author;
  private PersonIdent committer;

@@ -1050,17 +1054,31 @@ public void setPatchSets(Collection<PatchSet> patchSets) {
    this.hashtags = hashtags;
  }

+  @Deprecated
  public Set<Account.Id> starredBy() throws OrmException {
    if (starredByUser == null) {
-      starredByUser = checkNotNull(starredChangesUtil).byChange(legacyId);
+      starredByUser = checkNotNull(starredChangesUtil).byChange(
+          legacyId, StarredChangesUtil.DEFAULT_LABEL);
    }
    return starredByUser;
  }

+  @Deprecated
  public void setStarredBy(Set<Account.Id> starredByUser) {
    this.starredByUser = starredByUser;
  }

+  public ImmutableMultimap<Account.Id, String> stars() throws OrmException {
+    if (stars == null) {
+      stars = checkNotNull(starredChangesUtil).byChange(legacyId);
+    }
+    return stars;
+  }
+
+  public void setStars(Multimap<Account.Id, String> stars) {
+    this.stars = ImmutableMultimap.copyOf(stars);
+  }
+
  @AutoValue
  abstract static class ReviewedByEvent {
    private static ReviewedByEvent create(ChangeMessage msg) {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -35,6 +35,7 @@ import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PatchLineCommentsUtil;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.account.AccountResolver;
 import com.google.gerrit.server.account.CapabilityControl;
 import com.google.gerrit.server.account.GroupBackend;
@@ -138,6 +139,8 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
  public static final String FIELD_REVIEWEDBY = "reviewedby";
  public static final String FIELD_REVIEWER = "reviewer";
  public static final String FIELD_REVIEWERIN = "reviewerin";
+  public static final String FIELD_STAR = "star";
+  public static final String FIELD_STARBY = "starby";
  public static final String FIELD_STARREDBY = "starredby";
  public static final String FIELD_STATUS = "status";
  public static final String FIELD_TOPIC = "topic";
@@ -422,6 +425,10 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
      return starredby(self());
    }

+    if ("stars".equalsIgnoreCase(value)) {
+      return new HasStarsPredicate(self());
+    }
+
    if ("draft".equalsIgnoreCase(value)) {
      return draftby(self());
    }
@@ -645,6 +652,11 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
    return new MessagePredicate(args.index, text);
  }

+  @Operator
+  public Predicate<ChangeData> star(String label) throws QueryParseException {
+    return new StarPredicate(self(), label);
+  }
+
  @Operator
  public Predicate<ChangeData> starredby(String who)
      throws QueryParseException, OrmException {
@@ -663,6 +675,10 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
  @SuppressWarnings("deprecation")
  private Predicate<ChangeData> starredby(Account.Id who)
      throws QueryParseException {
+    if (args.getSchema().hasField(ChangeField.STAR)) {
+      return new StarPredicate(who, StarredChangesUtil.DEFAULT_LABEL);
+    }
+
    return args.getSchema().hasField(ChangeField.STARREDBY)
        ? new IsStarredByPredicate(who)
        : new IsStarredByLegacyPredicate(args.asUser(who));
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/HasStarsPredicate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/HasStarsPredicate.java
@@ -0,0 +1,44 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.server.index.IndexPredicate;
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gwtorm.server.OrmException;
+
+public class HasStarsPredicate extends IndexPredicate<ChangeData> {
+  private final Account.Id accountId;
+
+  HasStarsPredicate(Account.Id accountId) {
+    super(ChangeField.STARBY, accountId.toString());
+    this.accountId = accountId;
+  }
+
+  @Override
+  public boolean match(ChangeData cd) throws OrmException {
+    return cd.stars().containsKey(accountId);
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+
+  @Override
+  public String toString() {
+    return ChangeQueryBuilder.FIELD_STARBY + ":" + accountId;
+  }
+}
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/IsStarredByPredicate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/IsStarredByPredicate.java
@@ -19,6 +19,7 @@ import com.google.gerrit.server.index.IndexPredicate;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gwtorm.server.OrmException;

+@Deprecated
 class IsStarredByPredicate extends IndexPredicate<ChangeData> {
  private final Account.Id accountId;

--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/StarPredicate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/StarPredicate.java
@@ -0,0 +1,48 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.index.IndexPredicate;
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gwtorm.server.OrmException;
+
+public class StarPredicate extends IndexPredicate<ChangeData> {
+  private final Account.Id accountId;
+  private final String label;
+
+  StarPredicate(Account.Id accountId, String label) {
+    super(ChangeField.STAR,
+        StarredChangesUtil.StarField.create(accountId, label).toString());
+    this.accountId = accountId;
+    this.label = label;
+  }
+
+  @Override
+  public boolean match(ChangeData cd) throws OrmException {
+    return cd.stars().get(accountId).contains(label);
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+
+  @Override
+  public String toString() {
+    return ChangeQueryBuilder.FIELD_STAR + ":" + label;
+  }
+}
--- a/gerrit-server/src/test/java/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/gerrit-server/src/test/java/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -38,6 +38,7 @@ import com.google.gerrit.extensions.api.changes.Changes.QueryRequest;
 import com.google.gerrit.extensions.api.changes.DraftInput;
 import com.google.gerrit.extensions.api.changes.HashtagsInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
+import com.google.gerrit.extensions.api.changes.StarsInput;
 import com.google.gerrit.extensions.api.groups.GroupInput;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
@@ -55,6 +56,7 @@ import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.Sequences;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.account.AccountManager;
 import com.google.gerrit.server.account.AuthRequest;
 import com.google.gerrit.server.change.ChangeInserter;
@@ -94,6 +96,7 @@ import org.junit.Test;

 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -1240,6 +1243,35 @@ public abstract class AbstractQueryChangesTest extends GerritServerTests {
    assertQuery("starredby:" + user2);
  }

+  @Test
+  public void byStar() throws Exception {
+    TestRepository<Repo> repo = createProject("repo");
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChangeWithStatus(repo, Change.Status.MERGED));
+    insert(repo, newChangeWithStatus(repo, Change.Status.MERGED));
+
+    gApi.accounts()
+        .self()
+        .setStars(change1.getId().toString(),
+            new StarsInput(new HashSet<>(Arrays.asList("red", "blue"))));
+    gApi.accounts()
+        .self()
+        .setStars(change2.getId().toString(),
+            new StarsInput(new HashSet<>(Arrays.asList(
+                StarredChangesUtil.DEFAULT_LABEL, "green", "blue"))));
+
+    // check labeled stars
+    assertQuery("star:red", change1);
+    assertQuery("star:blue", change2, change1);
+    assertQuery("has:stars", change2, change1);
+
+    // check default star
+    assertQuery("has:star", change2);
+    assertQuery("is:starred", change2);
+    assertQuery("starredby:self", change2);
+    assertQuery("star:" + StarredChangesUtil.DEFAULT_LABEL, change2);
+  }
+
  @Test
  public void byFrom() throws Exception {
    TestRepository<Repo> repo = createProject("repo");