1 files changed, 110 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/account/GroupBackends.java b/java/com/google/gerrit/server/account/GroupBackends.java
new file mode 100644
index 0000000000..1b1551269f
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+++ b/java/com/google/gerrit/server/account/GroupBackends.java
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+// Copyright (C) 2012 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 static java.util.Comparator.comparing;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.common.data.GroupReference;
+import com.google.gerrit.server.project.ProjectState;
+import java.util.Collection;
+import java.util.Comparator;
+
+/** Utility class for dealing with a GroupBackend. */
+public class GroupBackends {
+
+  public static final Comparator<GroupReference> GROUP_REF_NAME_COMPARATOR =
+      comparing(GroupReference::getName);
+
+  /**
+   * Runs {@link GroupBackend#suggest(String, ProjectState)} and filters the result to return the
+   * best suggestion, or null if one does not exist.
+   *
+   * @param groupBackend the group backend
+   * @param name the name for which to suggest groups
+   * @return the best single GroupReference suggestion
+   */
+  @Nullable
+  public static GroupReference findBestSuggestion(GroupBackend groupBackend, String name) {
+    return findBestSuggestion(groupBackend, name, null);
+  }
+
+  /**
+   * Runs {@link GroupBackend#suggest(String, ProjectState)} and filters the result to return the
+   * best suggestion, or null if one does not exist.
+   *
+   * @param groupBackend the group backend
+   * @param name the name for which to suggest groups
+   * @param project the project for which to suggest groups
+   * @return the best single GroupReference suggestion
+   */
+  @Nullable
+  public static GroupReference findBestSuggestion(
+      GroupBackend groupBackend, String name, @Nullable ProjectState project) {
+    Collection<GroupReference> refs = groupBackend.suggest(name, project);
+    if (refs.size() == 1) {
+      return Iterables.getOnlyElement(refs);
+    }
+
+    for (GroupReference ref : refs) {
+      if (isExactSuggestion(ref, name)) {
+        return ref;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Runs {@link GroupBackend#suggest(String, ProjectState)} and filters the result to return the
+   * exact suggestion, or null if one does not exist.
+   *
+   * @param groupBackend the group backend
+   * @param name the name for which to suggest groups
+   * @return the exact single GroupReference suggestion
+   */
+  @Nullable
+  public static GroupReference findExactSuggestion(GroupBackend groupBackend, String name) {
+    return findExactSuggestion(groupBackend, name, null);
+  }
+
+  /**
+   * Runs {@link GroupBackend#suggest(String, ProjectState)} and filters the result to return the
+   * exact suggestion, or null if one does not exist.
+   *
+   * @param groupBackend the group backend
+   * @param name the name for which to suggest groups
+   * @param project the project for which to suggest groups
+   * @return the exact single GroupReference suggestion
+   */
+  @Nullable
+  public static GroupReference findExactSuggestion(
+      GroupBackend groupBackend, String name, ProjectState project) {
+    Collection<GroupReference> refs = groupBackend.suggest(name, project);
+    for (GroupReference ref : refs) {
+      if (isExactSuggestion(ref, name)) {
+        return ref;
+      }
+    }
+    return null;
+  }
+
+  /** Returns whether the GroupReference is an exact suggestion for the name. */
+  public static boolean isExactSuggestion(GroupReference ref, String name) {
+    return ref.getName().equalsIgnoreCase(name) || ref.getUUID().get().equals(name);
+  }
+
+  private GroupBackends() {}
+}