ChangeApi: Add method to check if a change is muted

Change-Id: Ie7e4194499a0f7401ddefaa30b1d3cb9729194a5

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/change/ChangeIT.java

@@ -3521,16 +3521,16 @@ public class ChangeIT extends AbstractDaemonTest {
     gApi.changes().id(r.getChangeId()).addReviewer(in);
 
     setApiUser(user);
-    assertThat(gApi.changes().id(r.getChangeId()).get().muted).isNull();
+    assertThat(gApi.changes().id(r.getChangeId()).muted()).isFalse();
     gApi.changes().id(r.getChangeId()).mute(true);
-    assertThat(gApi.changes().id(r.getChangeId()).get().muted).isTrue();
+    assertThat(gApi.changes().id(r.getChangeId()).muted()).isTrue();
 
     setApiUser(user2);
     sender.clear();
     amendChange(r.getChangeId());
 
     setApiUser(user);
-    assertThat(gApi.changes().id(r.getChangeId()).get().muted).isNull();
+    assertThat(gApi.changes().id(r.getChangeId()).muted()).isFalse();
 
     List<Message> messages = sender.getMessages();
     assertThat(messages).hasSize(1);

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/ChangeApi.java

@@ -125,6 +125,13 @@ public interface ChangeApi {
    */
   void mute(boolean mute) throws RestApiException;
 
+  /**
+   * Check if this change is muted.
+   *
+   * @return true if the change is muted.
+   */
+  boolean muted() throws RestApiException;
+
   /**
    * Create a new change that reverts this change.
    *
@@ -578,6 +585,11 @@ public interface ChangeApi {
       throw new NotImplementedException();
     }
 
+    @Override
+    public boolean muted() throws RestApiException {
+      throw new NotImplementedException();
+    }
+
     @Override
     public PureRevertInfo pureRevert() throws RestApiException {
       throw new NotImplementedException();

gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java

@@ -698,6 +698,15 @@ class ChangeApiImpl implements ChangeApi {
     }
   }
 
+  @Override
+  public boolean muted() throws RestApiException {
+    try {
+      return stars.isMutedBy(change.getChange(), change.getUser().getAccountId());
+    } catch (OrmException e) {
+      throw asRestApiException("Cannot check if muted", e);
+    }
+  }
+
   @Override
   public PureRevertInfo pureRevert() throws RestApiException {
     return pureRevert(null);