Factor out an AccountInfoComparator class to avoid code duplication

Add a new class that implements a comparator for AccountInfo that can
be used in multiple places.

The ordering for SuggestAccounts is slighty improved since it now also
sorts by account ID when name and email are equal.

Change-Id: If6fd06585e804ec1339f70d4928b87d9ac8cfa98
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/account/SuggestAccounts.java

@@ -15,8 +15,6 @@
 package com.google.gerrit.server.account;
 
 import com.google.common.base.Strings;
-import com.google.common.collect.ComparisonChain;
-import com.google.common.collect.Ordering;
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.RestReadView;
@@ -24,6 +22,7 @@ import com.google.gerrit.extensions.restapi.TopLevelResource;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountExternalId;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.api.accounts.AccountInfoComparator;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -33,7 +32,6 @@ import org.kohsuke.args4j.Option;
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -140,15 +138,7 @@ public class SuggestAccounts implements RestReadView<TopLevelResource> {
     }
 
     List<AccountInfo> m = new ArrayList<>(matches.values());
-    Collections.sort(m, new Comparator<AccountInfo>() {
-      @Override
-      public int compare(AccountInfo a, AccountInfo b) {
-        return ComparisonChain.start()
-          .compare(a.name, b.name, Ordering.natural().nullsLast())
-          .compare(a.email, b.email, Ordering.natural().nullsLast())
-          .result();
-      }
-    });
+    Collections.sort(m, AccountInfoComparator.ORDER_NULLS_LAST);
     return m;
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/api/accounts/AccountInfoComparator.java

@@ -0,0 +1,56 @@
+// Copyright (C) 2015 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.api.accounts;
+
+import com.google.common.collect.ComparisonChain;
+import com.google.common.collect.Ordering;
+import com.google.gerrit.extensions.common.AccountInfo;
+
+import java.util.Comparator;
+
+public class AccountInfoComparator extends Ordering<AccountInfo>
+    implements Comparator<AccountInfo> {
+  public static final AccountInfoComparator ORDER_NULLS_FIRST =
+      new AccountInfoComparator();
+  public static final AccountInfoComparator ORDER_NULLS_LAST =
+      new AccountInfoComparator().setNullsLast();
+
+  private boolean nullsLast;
+
+  private AccountInfoComparator() {
+  }
+
+  private AccountInfoComparator setNullsLast() {
+    this.nullsLast = true;
+    return this;
+  }
+
+  @Override
+  public int compare(AccountInfo a, AccountInfo b) {
+    return ComparisonChain.start()
+        .compare(a.name, b.name, createOrdering())
+        .compare(a.email, b.email, createOrdering())
+        .compare(a._accountId, b._accountId, createOrdering())
+        .result();
+  }
+
+  private <S extends Comparable<?>> Ordering<S> createOrdering() {
+    if (nullsLast) {
+      return Ordering.natural().nullsLast();
+    } else {
+      return Ordering.natural().nullsFirst();
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java

@@ -40,7 +40,6 @@ import com.google.common.base.Joiner;
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Optional;
 import com.google.common.base.Throwables;
-import com.google.common.collect.ComparisonChain;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.HashMultimap;
@@ -49,7 +48,6 @@ import com.google.common.collect.LinkedHashMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Multimap;
-import com.google.common.collect.Ordering;
 import com.google.common.collect.SetMultimap;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Table;
@@ -92,6 +90,7 @@ import com.google.gerrit.server.GpgException;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.WebLinks;
 import com.google.gerrit.server.account.AccountLoader;
+import com.google.gerrit.server.api.accounts.AccountInfoComparator;
 import com.google.gerrit.server.api.accounts.GpgApiAdapter;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.LabelNormalizer;
@@ -121,7 +120,6 @@ import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.List;
@@ -849,16 +847,7 @@ public class ChangeJson {
             return accountLoader.get(id);
           }
         })
-        .toSortedList(new Comparator<AccountInfo>() {
-          @Override
-          public int compare(AccountInfo a, AccountInfo b) {
-            return ComparisonChain.start()
-                .compare(a.name, b.name, Ordering.natural().nullsFirst())
-                .compare(a.email, b.email, Ordering.natural().nullsFirst())
-                .compare(a._accountId, b._accountId,
-                    Ordering.natural().nullsFirst()).result();
-          }
-        });
+        .toSortedList(AccountInfoComparator.ORDER_NULLS_FIRST);
   }
 
   private Map<String, RevisionInfo> revisions(ChangeControl ctl,

gerrit-server/src/main/java/com/google/gerrit/server/group/ListMembers.java

@@ -14,10 +14,8 @@
 
 package com.google.gerrit.server.group;
 
-import com.google.common.collect.ComparisonChain;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
-import com.google.common.collect.Ordering;
 import com.google.gerrit.common.data.GroupDetail;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.AccountInfo;
@@ -30,13 +28,13 @@ import com.google.gerrit.reviewdb.client.AccountGroupMember;
 import com.google.gerrit.server.account.AccountLoader;
 import com.google.gerrit.server.account.GroupCache;
 import com.google.gerrit.server.account.GroupDetailFactory;
+import com.google.gerrit.server.api.accounts.AccountInfoComparator;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 
 import org.kohsuke.args4j.Option;
 
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -82,15 +80,7 @@ public class ListMembers implements RestReadView<GroupResource> {
     final Map<Account.Id, AccountInfo> members =
         getMembers(groupId, new HashSet<AccountGroup.UUID>());
     final List<AccountInfo> memberInfos = Lists.newArrayList(members.values());
-    Collections.sort(memberInfos, new Comparator<AccountInfo>() {
-      @Override
-      public int compare(AccountInfo a, AccountInfo b) {
-        return ComparisonChain.start()
-            .compare(a.name, b.name, Ordering.natural().nullsFirst())
-            .compare(a.email, b.email, Ordering.natural().nullsFirst())
-            .compare(a._accountId, b._accountId, Ordering.natural().nullsFirst()).result();
-      }
-    });
+    Collections.sort(memberInfos, AccountInfoComparator.ORDER_NULLS_FIRST);
     return memberInfos;
   }