Convert some Functions/Predicates to streams & lambdas (4)

Change-Id: I8a3b8f1247df99f824c3b4d34c7573b5d16a10a4
2016-09-20 11:52:03 -04:00
parent 8c6540e84b
commit eed3ed3b1a
16 changed files with 100 additions and 208 deletions
--- a/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/TestAccount.java
+++ b/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/TestAccount.java
@@ -14,7 +14,6 @@

 package com.google.gerrit.acceptance;

-import com.google.common.base.Function;
 import com.google.common.collect.FluentIterable;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.server.mail.Address;
@@ -29,13 +28,7 @@ import java.util.Arrays;
 public class TestAccount {
  public static FluentIterable<Account.Id> ids(
      Iterable<TestAccount> accounts) {
-    return FluentIterable.from(accounts)
-        .transform(new Function<TestAccount, Account.Id>() {
-          @Override
-          public Account.Id apply(TestAccount in) {
-            return in.id;
-          }
-        });
+    return FluentIterable.from(accounts).transform(a -> a.id);
  }

  public static FluentIterable<Account.Id> ids(TestAccount... accounts) {
@@ -43,13 +36,7 @@ public class TestAccount {
  }

  public static FluentIterable<String> names(Iterable<TestAccount> accounts) {
-    return FluentIterable.from(accounts)
-        .transform(new Function<TestAccount, String>() {
-          @Override
-          public String apply(TestAccount in) {
-            return in.fullName;
-          }
-        });
+    return FluentIterable.from(accounts).transform(a -> a.fullName);
  }

  public static FluentIterable<String> names(TestAccount... accounts) {
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Init.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Init.java
@@ -14,9 +14,8 @@

 package com.google.gerrit.pgm;

-import com.google.common.base.Function;
 import com.google.common.base.Joiner;
-import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
 import com.google.gerrit.common.IoUtil;
 import com.google.gerrit.common.PageLinks;
 import com.google.gerrit.common.PluginData;
@@ -42,6 +41,7 @@ import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;

 /** Initialize a new Gerrit installation. */
 public class Init extends BaseInit {
@@ -237,16 +237,10 @@ public class Init extends BaseInit {
    if (nullOrEmpty(installPlugins) || nullOrEmpty(plugins)) {
      return;
    }
-    ArrayList<String> copy = Lists.newArrayList(installPlugins);
-    List<String> pluginNames = Lists.transform(plugins, new Function<PluginData, String>() {
-      @Override
-      public String apply(PluginData input) {
-        return input.name;
-      }
-    });
-    copy.removeAll(pluginNames);
-    if (!copy.isEmpty()) {
-      ui.message("Cannot find plugin(s): %s\n", Joiner.on(", ").join(copy));
+    Set<String> missing = Sets.newHashSet(installPlugins);
+    plugins.stream().forEach(p -> missing.remove(p.name));
+    if (!missing.isEmpty()) {
+      ui.message("Cannot find plugin(s): %s\n", Joiner.on(", ").join(missing));
      listPlugins = true;
    }
  }
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/RebuildNoteDb.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/RebuildNoteDb.java
@@ -17,7 +17,6 @@ package com.google.gerrit.pgm;
 import static com.google.gerrit.reviewdb.server.ReviewDbUtil.unwrapDb;
 import static com.google.gerrit.server.schema.DataSourceProvider.Context.MULTI_USER;

-import com.google.common.base.Function;
 import com.google.common.base.Predicates;
 import com.google.common.base.Stopwatch;
 import com.google.common.collect.ArrayListMultimap;
@@ -234,13 +233,8 @@ public class RebuildNoteDb extends SiteProgram {
        ArrayListMultimap.create();
    try (ReviewDb db = schemaFactory.open()) {
      if (projects.isEmpty() && !changes.isEmpty()) {
-        Iterable<Change> todo = unwrapDb(db).changes().get(
-            Iterables.transform(changes, new Function<Integer, Change.Id>() {
-              @Override
-              public Change.Id apply(Integer in) {
-                return new Change.Id(in);
-              }
-            }));
+        Iterable<Change> todo = unwrapDb(db).changes()
+            .get(Iterables.transform(changes, Change.Id::new));
        for (Change c : todo) {
          changesByProject.put(c.getProject(), c.getId());
        }
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java
@@ -16,10 +16,8 @@ package com.google.gerrit.pgm;

 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.gerrit.server.schema.DataSourceProvider.Context.MULTI_USER;
+import static java.util.stream.Collectors.toSet;

-import com.google.common.base.Function;
-import com.google.common.collect.FluentIterable;
-import com.google.common.collect.Ordering;
 import com.google.common.collect.Sets;
 import com.google.gerrit.common.Die;
 import com.google.gerrit.extensions.config.FactoryModule;
@@ -134,14 +132,8 @@ public class Reindex extends SiteProgram {
    }

    checkNotNull(indexDefs, "Called this method before injectMembers?");
-    Set<String> valid = FluentIterable.from(indexDefs).transform(
-        new Function<IndexDefinition<?, ?, ?>, String>() {
-          @Override
-          public String apply(IndexDefinition<?, ?, ?> input) {
-            return input.getName();
-          }
-        }).toSortedSet(Ordering.natural());
-
+    Set<String> valid = indexDefs.stream()
+        .map(IndexDefinition::getName).sorted().collect(toSet());
    Set<String> invalid = Sets.difference(Sets.newHashSet(indices), valid);
    if (invalid.isEmpty()) {
      return;
--- a/gerrit-server/src/main/java/com/google/gerrit/server/ChangeUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/ChangeUtil.java
@@ -14,7 +14,8 @@

 package com.google.gerrit.server;

-import com.google.common.base.Function;
+import static java.util.Comparator.comparingInt;
+
 import com.google.common.collect.Ordering;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.server.ReviewDb;
@@ -40,16 +41,8 @@ public class ChangeUtil {
  private static final String SUBJECT_CROP_APPENDIX = "...";
  private static final int SUBJECT_CROP_RANGE = 10;

-  public static final Function<PatchSet, Integer> TO_PS_ID =
-      new Function<PatchSet, Integer>() {
-        @Override
-        public Integer apply(PatchSet in) {
-          return in.getId().get();
-        }
-      };
-
-  public static final Ordering<PatchSet> PS_ID_ORDER = Ordering.natural()
-    .onResultOf(TO_PS_ID);
+  public static final Ordering<PatchSet> PS_ID_ORDER =
+      Ordering.from(comparingInt(PatchSet::getPatchSetId));

  /**
   * Generate a new unique identifier for change message entities.
--- a/gerrit-server/src/main/java/com/google/gerrit/server/OptionUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/OptionUtil.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.server;

 import com.google.common.base.CharMatcher;
-import com.google.common.base.Function;
 import com.google.common.base.Splitter;
 import com.google.common.collect.Iterables;

@@ -24,16 +23,10 @@ public class OptionUtil {
  private static final Splitter COMMA_OR_SPACE =
      Splitter.on(CharMatcher.anyOf(", ")).omitEmptyStrings().trimResults();

-  private static final Function<String, String> TO_LOWER_CASE =
-      new Function<String, String>() {
-        @Override
-        public String apply(String input) {
-          return input.toLowerCase();
-        }
-      };
-
  public static Iterable<String> splitOptionValue(String value) {
-    return Iterables.transform(COMMA_OR_SPACE.split(value), TO_LOWER_CASE);
+    return Iterables.transform(
+        COMMA_OR_SPACE.split(value),
+        String::toLowerCase);
  }

  private OptionUtil() {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/ReviewersUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/ReviewersUtil.java
@@ -14,14 +14,14 @@

 package com.google.gerrit.server;

-import com.google.common.base.Function;
+import static java.util.Comparator.comparing;
+
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Ordering;
-import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.AccountInfo;
@@ -68,10 +68,8 @@ import java.util.Set;
 public class ReviewersUtil {
  private static final String MAX_SUFFIX = "\u9fa5";
  private static final Ordering<SuggestedReviewerInfo> ORDERING =
-      Ordering.natural().onResultOf(new Function<SuggestedReviewerInfo, String>() {
-        @Nullable
-        @Override
-        public String apply(@Nullable SuggestedReviewerInfo suggestedReviewerInfo) {
+      Ordering.from(comparing(
+          suggestedReviewerInfo -> {
            if (suggestedReviewerInfo == null) {
              return null;
            }
@@ -79,8 +77,8 @@ public class ReviewersUtil {
                ? MoreObjects.firstNonNull(suggestedReviewerInfo.account.email,
                Strings.nullToEmpty(suggestedReviewerInfo.account.name))
                : Strings.nullToEmpty(suggestedReviewerInfo.group.name);
-        }
-      });
+          }));
+
  private final AccountLoader accountLoader;
  private final AccountCache accountCache;
  private final AccountIndexCollection indexes;
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/AllowedFormats.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/AllowedFormats.java
@@ -14,8 +14,9 @@

 package com.google.gerrit.server.change;

-import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
 import com.google.gerrit.server.config.DownloadConfig;
 import com.google.inject.Inject;
@@ -28,7 +29,7 @@ import java.util.Set;
@Singleton
 public class AllowedFormats {
  final ImmutableMap<String, ArchiveFormat> extensions;
-  final Set<ArchiveFormat> allowed;
+  final ImmutableSet<ArchiveFormat> allowed;

  @Inject
  AllowedFormats(DownloadConfig cfg) {
@@ -43,14 +44,8 @@ public class AllowedFormats {

    // Zip is not supported because it may be interpreted by a Java plugin as a
    // valid JAR file, whose code would have access to cookies on the domain.
-    allowed = Sets.filter(
-        cfg.getArchiveFormats(),
-        new Predicate<ArchiveFormat>() {
-          @Override
-          public boolean apply(ArchiveFormat format) {
-            return (format != ArchiveFormat.ZIP);
-          }
-        });
+    allowed = Sets.immutableEnumSet(
+        Iterables.filter(cfg.getArchiveFormats(), f -> f != ArchiveFormat.ZIP));
  }

  public Set<ArchiveFormat> getAllowed() {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeInserter.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeInserter.java
@@ -18,9 +18,9 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.reviewdb.client.Change.INITIAL_PATCH_SET_ID;

+import static java.util.stream.Collectors.toSet;
+
 import com.google.common.base.MoreObjects;
-import com.google.common.base.Predicate;
-import com.google.common.collect.Sets;
 import com.google.gerrit.common.FooterConstants;
 import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.LabelTypes;
@@ -377,21 +377,23 @@ public class ChangeInserter extends BatchUpdate.InsertChangeOp {

  private Set<Account.Id> filterOnChangeVisibility(final ReviewDb db,
      final ChangeNotes notes, Set<Account.Id> accounts) {
-    return Sets.filter(accounts, new Predicate<Account.Id>() {
-      @Override
-      public boolean apply(Account.Id accountId) {
+    return accounts.stream()
+        .filter(
+            accountId -> {
              try {
                IdentifiedUser user = userFactory.create(accountId);
-          return changeControlFactory.controlFor(notes, user).isVisible(db);
+                return changeControlFactory.controlFor(notes, user)
+                    .isVisible(db);
              } catch (OrmException | NoSuchChangeException e) {
                log.warn(
-              String.format("Failed to check if account %d can see change %d",
+                    String.format(
+                        "Failed to check if account %d can see change %d",
                        accountId.get(), notes.getChangeId().get()),
                    e);
                return false;
              }
-      }
-    });
+            })
+        .collect(toSet());
  }

  @Override
--- 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
@@ -35,8 +35,9 @@ import static com.google.gerrit.extensions.client.ListChangesOption.REVIEWER_UPD
 import static com.google.gerrit.extensions.client.ListChangesOption.WEB_LINKS;
 import static com.google.gerrit.server.CommonConverters.toGitPerson;

+import static java.util.stream.Collectors.toList;
+
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Function;
 import com.google.common.base.Joiner;
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Optional;
@@ -298,13 +299,8 @@ public class ChangeJson {
  public List<List<ChangeInfo>> formatQueryResults(
      List<QueryResult<ChangeData>> in) throws OrmException {
    accountLoader = accountLoaderFactory.create(has(DETAILED_ACCOUNTS));
-    ensureLoaded(FluentIterable.from(in).transformAndConcat(
-        new Function<QueryResult<ChangeData>, List<ChangeData>>() {
-          @Override
-          public List<ChangeData> apply(QueryResult<ChangeData> in) {
-            return in.entities();
-          }
-        }));
+    ensureLoaded(
+        FluentIterable.from(in).transformAndConcat(QueryResult::entities));

    List<List<ChangeInfo>> res = Lists.newArrayListWithCapacity(in.size());
    Map<Change.Id, ChangeInfo> out = new HashMap<>();
@@ -599,7 +595,7 @@ public class ChangeJson {
      ? labelsForOpenChange(ctl, cd, labelTypes, standard, detailed)
      : labelsForClosedChange(cd, labelTypes, standard, detailed);
    return ImmutableMap.copyOf(
-        Maps.transformValues(withStatus, LabelWithStatus.TO_LABEL_INFO));
+        Maps.transformValues(withStatus, LabelWithStatus::label));
  }

  private Map<String, LabelWithStatus> labelsForOpenChange(ChangeControl ctl,
@@ -952,14 +948,10 @@ public class ChangeJson {

  private Collection<AccountInfo> toAccountInfo(
      Collection<Account.Id> accounts) {
-    return FluentIterable.from(accounts)
-        .transform(new Function<Account.Id, AccountInfo>() {
-          @Override
-          public AccountInfo apply(Account.Id id) {
-            return accountLoader.get(id);
-          }
-        })
-        .toSortedList(AccountInfoComparator.ORDER_NULLS_FIRST);
+    return accounts.stream()
+        .map(accountLoader::get)
+        .sorted(AccountInfoComparator.ORDER_NULLS_FIRST)
+        .collect(toList());
  }

  @Nullable
@@ -1185,14 +1177,6 @@ public class ChangeJson {

  @AutoValue
  abstract static class LabelWithStatus {
-    private static final Function<LabelWithStatus, LabelInfo> TO_LABEL_INFO =
-        new Function<LabelWithStatus, LabelInfo>() {
-          @Override
-          public LabelInfo apply(LabelWithStatus in) {
-            return in.label();
-          }
-        };
-
    private static LabelWithStatus create(LabelInfo label,
        SubmitRecord.Label.Status status) {
      return new AutoValue_ChangeJson_LabelWithStatus(label, status);
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java
@@ -16,7 +16,6 @@ package com.google.gerrit.server.change;

 import static com.google.gerrit.server.PatchLineCommentsUtil.COMMENT_INFO_ORDER;

-import com.google.common.base.Function;
 import com.google.common.base.Strings;
 import com.google.common.collect.FluentIterable;
 import com.google.gerrit.extensions.client.Comment.Range;
@@ -100,17 +99,13 @@ class CommentJson {

  List<CommentInfo> formatAsList(Iterable<PatchLineComment> l)
      throws OrmException {
-    final AccountLoader accountLoader = fillAccounts
+    AccountLoader accountLoader = fillAccounts
        ? accountLoaderFactory.create(true)
        : null;
    List<CommentInfo> out = FluentIterable
        .from(l)
-        .transform(new Function<PatchLineComment, CommentInfo>() {
-          @Override
-          public CommentInfo apply(PatchLineComment c) {
-            return toCommentInfo(c, accountLoader);
-          }
-        }).toSortedList(COMMENT_INFO_ORDER);
+        .transform(c -> toCommentInfo(c, accountLoader))
+        .toSortedList(COMMENT_INFO_ORDER);

    if (accountLoader != null) {
      accountLoader.fill();
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ConsistencyChecker.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ConsistencyChecker.java
@@ -19,13 +19,10 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.gerrit.reviewdb.client.RefNames.REFS_CHANGES;
 import static com.google.gerrit.reviewdb.server.ReviewDbUtil.intKeyOrdering;
 import static com.google.gerrit.server.ChangeUtil.PS_ID_ORDER;
-import static com.google.gerrit.server.ChangeUtil.TO_PS_ID;

 import com.google.auto.value.AutoValue;
-import com.google.common.base.Function;
 import com.google.common.collect.Collections2;
 import com.google.common.collect.Iterables;
-import com.google.common.collect.Lists;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.MultimapBuilder;
 import com.google.gerrit.common.FooterConstants;
@@ -256,12 +253,9 @@ public class ConsistencyChecker {
    Map<String, Ref> refs;
    try {
      refs = repo.getRefDatabase().exactRef(
-        Lists.transform(all, new Function<PatchSet, String>() {
-          @Override
-          public String apply(PatchSet ps) {
-            return ps.getId().toRefName();
-          }
-        }).toArray(new String[all.size()]));
+          all.stream()
+              .map(ps -> ps.getId().toRefName())
+              .toArray(String[]::new));
    } catch (IOException e) {
      error("error reading refs", e);
      refs = Collections.emptyMap();
@@ -319,7 +313,7 @@ public class ConsistencyChecker {
      if (e.getValue().size() > 1) {
        problem(String.format("Multiple patch sets pointing to %s: %s",
            e.getKey().name(),
-            Collections2.transform(e.getValue(), TO_PS_ID)));
+            Collections2.transform(e.getValue(), PatchSet::getPatchSetId)));
      }
    }

--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteReviewer.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteReviewer.java
@@ -14,7 +14,6 @@

 package com.google.gerrit.server.change;

-import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.gerrit.common.TimeUtil;
@@ -210,7 +209,7 @@ public class DeleteReviewer
    }

    private Iterable<PatchSetApproval> approvals(ChangeContext ctx,
-        final Account.Id accountId) throws OrmException {
+        Account.Id accountId) throws OrmException {
      Change.Id changeId = ctx.getNotes().getChangeId();
      Iterable<PatchSetApproval> approvals;

@@ -229,14 +228,7 @@ public class DeleteReviewer
            approvalsUtil.byChange(ctx.getDb(), ctx.getNotes()).values();
      }

-      return Iterables.filter(
-          approvals,
-          new Predicate<PatchSetApproval>() {
-            @Override
-            public boolean apply(PatchSetApproval input) {
-              return accountId.equals(input.getAccountId());
-            }
-          });
+      return Iterables.filter(approvals, accountId::equals);
    }

    private String formatLabelValue(short value) {
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReviewers.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReviewers.java
@@ -17,7 +17,6 @@ package com.google.gerrit.server.change;
 import static com.google.gerrit.extensions.client.ReviewerState.CC;
 import static com.google.gerrit.extensions.client.ReviewerState.REVIEWER;

-import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
@@ -357,13 +356,8 @@ public class PostReviewers
        }
        emailReviewers(rsrc.getChange(), addedReviewers, addedCCs);
        if (!addedReviewers.isEmpty()) {
-          List<Account.Id> reviewers = Lists.transform(addedReviewers,
-              new Function<PatchSetApproval, Account.Id>() {
-                @Override
-                public Account.Id apply(PatchSetApproval psa) {
-                  return psa.getAccountId();
-                }
-              });
+          List<Account.Id> reviewers =
+              Lists.transform(addedReviewers, PatchSetApproval::getAccountId);
          reviewerAdded.fire(rsrc.getChange(), patchSet, reviewers,
              ctx.getAccount(), ctx.getWhen());
        }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Submit.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Submit.java
@@ -14,15 +14,13 @@

 package com.google.gerrit.server.change;

+import static java.util.stream.Collectors.joining;
+
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Function;
-import com.google.common.base.Joiner;
 import com.google.common.base.MoreObjects;
-import com.google.common.base.Predicate;
 import com.google.common.base.Strings;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Iterables;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Sets;
 import com.google.gerrit.common.data.ParameterizedString;
@@ -282,14 +280,10 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
            return CHANGE_UNMERGEABLE;
          }
        }
-        return CHANGES_NOT_MERGEABLE + Joiner.on(", ").join(
-            Iterables.transform(unmergeable,
-                new Function<ChangeData, String>() {
-              @Override
-              public String apply(ChangeData cd) {
-                return String.valueOf(cd.getId().get());
-              }
-            }));
+        return CHANGES_NOT_MERGEABLE +
+            unmergeable.stream()
+                .map(c -> c.getId().toString())
+                .collect(joining(", "));
      }
    } catch (ResourceConflictException e) {
      return BLOCKED_SUBMIT_TOOLTIP;
@@ -405,14 +399,10 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
   */
  public ChangeMessage getConflictMessage(RevisionResource rsrc)
      throws OrmException {
-    return FluentIterable.from(cmUtil.byPatchSet(dbProvider.get(), rsrc.getNotes(),
-        rsrc.getPatchSet().getId()))
-        .filter(new Predicate<ChangeMessage>() {
-          @Override
-          public boolean apply(ChangeMessage input) {
-            return input.getAuthor() == null;
-          }
-        })
+    return FluentIterable.from(
+            cmUtil.byPatchSet(
+                dbProvider.get(), rsrc.getNotes(), rsrc.getPatchSet().getId()))
+        .filter(cm -> cm.getAuthor() == null)
        .last()
        .orNull();
  }
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/WalkSorter.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/WalkSorter.java
@@ -18,7 +18,6 @@ import static com.google.common.base.Preconditions.checkState;

 import com.google.auto.value.AutoValue;
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Function;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
@@ -72,11 +71,8 @@ class WalkSorter {
      LoggerFactory.getLogger(WalkSorter.class);

  private static final Ordering<List<PatchSetData>> PROJECT_LIST_SORTER =
-      Ordering.natural().nullsFirst()
-          .onResultOf(
-            new Function<List<PatchSetData>, Project.NameKey>() {
-              @Override
-              public Project.NameKey apply(List<PatchSetData> in) {
+      Ordering.natural().nullsFirst().onResultOf(
+          (List<PatchSetData> in) -> {
            if (in == null || in.isEmpty()) {
              return null;
            }
@@ -85,7 +81,6 @@ class WalkSorter {
            } catch (OrmException e) {
              throw new IllegalStateException(e);
            }
-              }
          });

  private final GitRepositoryManager repoManager;