Introduce Delegating ActionListener Wrappers (#40129)

* Introduce Delegating ActionListener Wrappers
* Dry up use cases of ActionListener that simply pass through the response or exception to another listener

server/src/main/java/org/elasticsearch/action/ActionListener.java

@@ -72,6 +72,53 @@ public void onFailure(Exception e) {
         };
     }
 
+    /**
+     * Creates a listener that delegates all responses it receives to another listener.
+     *
+     * @param delegate ActionListener to wrap and delegate any exception to
+     * @param bc BiConsumer invoked with delegate listener and exception
+     * @param <T> Type of the listener
+     * @return Delegating listener
+     */
+    static <T> ActionListener<T> delegateResponse(ActionListener<T> delegate, BiConsumer<ActionListener<T>, Exception> bc) {
+        return new ActionListener<T>() {
+
+            @Override
+            public void onResponse(T r) {
+                delegate.onResponse(r);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                bc.accept(delegate, e);
+            }
+        };
+    }
+
+    /**
+     * Creates a listener that delegates all exceptions it receives to another listener.
+     *
+     * @param delegate ActionListener to wrap and delegate any exception to
+     * @param bc BiConsumer invoked with delegate listener and response
+     * @param <T> Type of the delegating listener's response
+     * @param <R> Type of the wrapped listeners
+     * @return Delegating listener
+     */
+    static <T, R> ActionListener<T> delegateFailure(ActionListener<R> delegate, BiConsumer<ActionListener<R>, T> bc) {
+        return new ActionListener<T>() {
+
+            @Override
+            public void onResponse(T r) {
+                bc.accept(delegate, r);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                delegate.onFailure(e);
+            }
+        };
+    }
+
     /**
      * Creates a listener that listens for a response (or failure) and executes the
      * corresponding runnable when the response (or failure) is received.

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/get/TransportGetTaskAction.java

@@ -157,7 +157,7 @@ void getRunningTaskFromNode(Task thisTask, GetTaskRequest request, ActionListene
                 // Shift to the generic thread pool and let it wait for the task to complete so we don't block any important threads.
                 threadPool.generic().execute(new AbstractRunnable() {
                     @Override
-                    protected void doRun() throws Exception {
+                    protected void doRun() {
                         taskManager.waitForTaskCompletion(runningTask, waitForCompletionTimeout(request.getTimeout()));
                         waitedForCompletion(thisTask, request, runningTask.taskInfo(clusterService.localNode().getId(), true), listener);
                     }
@@ -180,26 +180,17 @@ public void onFailure(Exception e) {
      */
     void waitedForCompletion(Task thisTask, GetTaskRequest request, TaskInfo snapshotOfRunningTask,
             ActionListener<GetTaskResponse> listener) {
-        getFinishedTaskFromIndex(thisTask, request, new ActionListener<GetTaskResponse>() {
-            @Override
-            public void onResponse(GetTaskResponse response) {
-                // We were able to load the task from the task index. Let's send that back.
-                listener.onResponse(response);
-            }
-
-            @Override
-            public void onFailure(Exception e) {
+        getFinishedTaskFromIndex(thisTask, request, ActionListener.delegateResponse(listener, (delegatedListener, e) -> {
                 /*
                  * We couldn't load the task from the task index. Instead of 404 we should use the snapshot we took after it finished. If
                  * the error isn't a 404 then we'll just throw it back to the user.
                  */
                 if (ExceptionsHelper.unwrap(e, ResourceNotFoundException.class) != null) {
-                    listener.onResponse(new GetTaskResponse(new TaskResult(true, snapshotOfRunningTask)));
+                    delegatedListener.onResponse(new GetTaskResponse(new TaskResult(true, snapshotOfRunningTask)));
                 } else {
-                    listener.onFailure(e);
+                    delegatedListener.onFailure(e);
                 }
-            }
-        });
+        }));
     }
 
     /**

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.action.support.master.TransportMasterNodeAction;
 import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.ack.ClusterStateUpdateResponse;
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
@@ -69,17 +68,8 @@ protected ClusterBlockException checkBlock(DeleteRepositoryRequest request, Clus
     protected void masterOperation(final DeleteRepositoryRequest request, ClusterState state,
                                    final ActionListener<AcknowledgedResponse> listener) {
         repositoriesService.unregisterRepository(
-            request,
-            new ActionListener<ClusterStateUpdateResponse>() {
-                @Override
-                public void onResponse(ClusterStateUpdateResponse unregisterRepositoryResponse) {
-                    listener.onResponse(new AcknowledgedResponse(unregisterRepositoryResponse.isAcknowledged()));
-                }
-
-                @Override
-                public void onFailure(Exception e) {
-                    listener.onFailure(e);
-                }
-            });
+            request, ActionListener.delegateFailure(listener,
+                (delegatedListener, unregisterRepositoryResponse) ->
+                    delegatedListener.onResponse(new AcknowledgedResponse(unregisterRepositoryResponse.isAcknowledged()))));
     }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/TransportPutRepositoryAction.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.action.support.master.TransportMasterNodeAction;
 import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.ack.ClusterStateUpdateResponse;
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
@@ -68,17 +67,7 @@ protected ClusterBlockException checkBlock(PutRepositoryRequest request, Cluster
     @Override
     protected void masterOperation(final PutRepositoryRequest request, ClusterState state,
                                    final ActionListener<AcknowledgedResponse> listener) {
-        repositoriesService.registerRepository(request, new ActionListener<ClusterStateUpdateResponse>() {
-
-            @Override
-            public void onResponse(ClusterStateUpdateResponse response) {
-                listener.onResponse(new AcknowledgedResponse(response.isAcknowledged()));
-            }
-
-            @Override
-            public void onFailure(Exception e) {
-                listener.onFailure(e);
-            }
-        });
+        repositoriesService.registerRepository(request, ActionListener.delegateFailure(listener,
+            (delegatedListener, response) -> delegatedListener.onResponse(new AcknowledgedResponse(response.isAcknowledged()))));
     }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java

@@ -33,8 +33,6 @@
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
-import java.util.List;
-
 /**
  * Transport action for verifying repository operation
  */
@@ -70,16 +68,8 @@ protected ClusterBlockException checkBlock(VerifyRepositoryRequest request, Clus
     @Override
     protected void masterOperation(final VerifyRepositoryRequest request, ClusterState state,
                                    final ActionListener<VerifyRepositoryResponse> listener) {
-        repositoriesService.verifyRepository(request.name(), new ActionListener<List<DiscoveryNode>>() {
-            @Override
-            public void onResponse(List<DiscoveryNode> verifyResponse) {
-                listener.onResponse(new VerifyRepositoryResponse(verifyResponse.toArray(new DiscoveryNode[0])));
-            }
-
-            @Override
-            public void onFailure(Exception e) {
-                listener.onFailure(e);
-            }
-        });
+        repositoriesService.verifyRepository(request.name(), ActionListener.delegateFailure(listener,
+            (delegatedListener, verifyResponse) ->
+                delegatedListener.onResponse(new VerifyRepositoryResponse(verifyResponse.toArray(new DiscoveryNode[0])))));
     }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java

@@ -29,7 +29,6 @@
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.snapshots.RestoreService;
-import org.elasticsearch.snapshots.RestoreService.RestoreCompletionResponse;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
@@ -75,20 +74,13 @@ protected ClusterBlockException checkBlock(RestoreSnapshotRequest request, Clust
     @Override
     protected void masterOperation(final RestoreSnapshotRequest request, final ClusterState state,
                                    final ActionListener<RestoreSnapshotResponse> listener) {
-        restoreService.restoreSnapshot(request, new ActionListener<RestoreCompletionResponse>() {
-            @Override
-            public void onResponse(RestoreCompletionResponse restoreCompletionResponse) {
+        restoreService.restoreSnapshot(request, ActionListener.delegateFailure(listener,
+            (delegatedListener, restoreCompletionResponse) -> {
                 if (restoreCompletionResponse.getRestoreInfo() == null && request.waitForCompletion()) {
-                    RestoreClusterStateListener.createAndRegisterListener(clusterService, restoreCompletionResponse, listener);
+                    RestoreClusterStateListener.createAndRegisterListener(clusterService, restoreCompletionResponse, delegatedListener);
                 } else {
-                    listener.onResponse(new RestoreSnapshotResponse(restoreCompletionResponse.getRestoreInfo()));
+                    delegatedListener.onResponse(new RestoreSnapshotResponse(restoreCompletionResponse.getRestoreInfo()));
                 }
-            }
-
-            @Override
-            public void onFailure(Exception t) {
-                listener.onFailure(t);
-            }
-        });
+            }));
     }
 }

server/src/main/java/org/elasticsearch/action/admin/indices/close/TransportCloseIndexAction.java

@@ -118,19 +118,9 @@ protected void masterOperation(final Task task,
             .masterNodeTimeout(request.masterNodeTimeout())
             .waitForActiveShards(request.waitForActiveShards())
             .indices(concreteIndices);
-
-        indexStateService.closeIndices(closeRequest, new ActionListener<CloseIndexResponse>() {
-
-            @Override
-            public void onResponse(final CloseIndexResponse response) {
-                listener.onResponse(response);
-            }
-
-            @Override
-            public void onFailure(final Exception t) {
-                logger.debug(() -> new ParameterizedMessage("failed to close indices [{}]", (Object) concreteIndices), t);
-                listener.onFailure(t);
-            }
-        });
+        indexStateService.closeIndices(closeRequest, ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
+            logger.debug(() -> new ParameterizedMessage("failed to close indices [{}]", (Object) concreteIndices), t);
+            delegatedListener.onFailure(t);
+        }));
     }
 }

server/src/main/java/org/elasticsearch/action/admin/indices/shrink/TransportResizeAction.java

@@ -24,7 +24,6 @@
 import org.elasticsearch.action.admin.indices.create.CreateIndexClusterStateUpdateRequest;
 import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
 import org.elasticsearch.action.admin.indices.stats.IndexShardStats;
-import org.elasticsearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.master.TransportMasterNodeAction;
 import org.elasticsearch.client.Client;
@@ -97,25 +96,18 @@ protected void masterOperation(final ResizeRequest resizeRequest, final ClusterS
         // there is no need to fetch docs stats for split but we keep it simple and do it anyway for simplicity of the code
         final String sourceIndex = indexNameExpressionResolver.resolveDateMathExpression(resizeRequest.getSourceIndex());
         final String targetIndex = indexNameExpressionResolver.resolveDateMathExpression(resizeRequest.getTargetIndexRequest().index());
-        client.admin().indices().prepareStats(sourceIndex).clear().setDocs(true).execute(new ActionListener<IndicesStatsResponse>() {
-            @Override
-            public void onResponse(IndicesStatsResponse indicesStatsResponse) {
+        client.admin().indices().prepareStats(sourceIndex).clear().setDocs(true).execute(
+            ActionListener.delegateFailure(listener, (delegatedListener, indicesStatsResponse) -> {
                 CreateIndexClusterStateUpdateRequest updateRequest = prepareCreateIndexRequest(resizeRequest, state,
-                    (i) -> {
+                    i -> {
                         IndexShardStats shard = indicesStatsResponse.getIndex(sourceIndex).getIndexShards().get(i);
                         return shard == null ? null : shard.getPrimary().getDocs();
                     }, sourceIndex, targetIndex);
                 createIndexService.createIndex(
-                    updateRequest, ActionListener.map(listener,
+                    updateRequest, ActionListener.map(delegatedListener,
                         response -> new ResizeResponse(response.isAcknowledged(), response.isShardsAcknowledged(), updateRequest.index()))
                 );
-            }
-
-            @Override
-            public void onFailure(Exception e) {
-                listener.onFailure(e);
-            }
-        });
+            }));
 
     }
 

server/src/main/java/org/elasticsearch/action/admin/indices/upgrade/post/TransportUpgradeAction.java

@@ -25,7 +25,6 @@
 import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.DefaultShardOperationFailedException;
 import org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
-import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.block.ClusterBlockException;
@@ -104,7 +103,7 @@ protected UpgradeResponse newResponse(UpgradeRequest request, int totalShards, i
                 versions.put(index, new Tuple<>(version, luceneVersion));
             }
         }
-        Map<String, Tuple<org.elasticsearch.Version, String>> updatedVersions = new HashMap<>();
+        Map<String, Tuple<Version, String>> updatedVersions = new HashMap<>();
         MetaData metaData = clusterState.metaData();
         for (Map.Entry<String, Tuple<Version, org.apache.lucene.util.Version>> versionEntry : versions.entrySet()) {
             String index = versionEntry.getKey();
@@ -209,16 +208,7 @@ public void onFailure(Exception e) {
 
     private void updateSettings(final UpgradeResponse upgradeResponse, final ActionListener<UpgradeResponse> listener) {
         UpgradeSettingsRequest upgradeSettingsRequest = new UpgradeSettingsRequest(upgradeResponse.versions());
-        client.executeLocally(UpgradeSettingsAction.INSTANCE, upgradeSettingsRequest, new ActionListener<AcknowledgedResponse>() {
-            @Override
-            public void onResponse(AcknowledgedResponse updateSettingsResponse) {
-                listener.onResponse(upgradeResponse);
-            }
-
-            @Override
-            public void onFailure(Exception e) {
-                listener.onFailure(e);
-            }
-        });
+        client.executeLocally(UpgradeSettingsAction.INSTANCE, upgradeSettingsRequest, ActionListener.delegateFailure(
+            listener, (delegatedListener, updateSettingsResponse) -> delegatedListener.onResponse(upgradeResponse)));
     }
 }

server/src/main/java/org/elasticsearch/action/bulk/TransportBulkAction.java

@@ -658,7 +658,15 @@ ActionListener<BulkResponse> wrapActionListenerIfNeeded(long ingestTookInMillis,
                 return ActionListener.map(actionListener,
                     response -> new BulkResponse(response.getItems(), response.getTook().getMillis(), ingestTookInMillis));
             } else {
-                return new IngestBulkResponseListener(ingestTookInMillis, originalSlots, itemResponses, actionListener);
+                return ActionListener.delegateFailure(actionListener, (delegatedListener, response) -> {
+                    BulkItemResponse[] items = response.getItems();
+                    for (int i = 0; i < items.length; i++) {
+                        itemResponses.add(originalSlots[i], response.getItems()[i]);
+                    }
+                    delegatedListener.onResponse(
+                        new BulkResponse(
+                            itemResponses.toArray(new BulkItemResponse[0]), response.getTook().getMillis(), ingestTookInMillis));
+                });
             }
         }
 
@@ -688,36 +696,4 @@ void markCurrentItemAsFailed(Exception e) {
         }
 
     }
-
-    static final class IngestBulkResponseListener implements ActionListener<BulkResponse> {
-
-        private final long ingestTookInMillis;
-        private final int[] originalSlots;
-        private final List<BulkItemResponse> itemResponses;
-        private final ActionListener<BulkResponse> actionListener;
-
-        IngestBulkResponseListener(long ingestTookInMillis, int[] originalSlots, List<BulkItemResponse> itemResponses,
-                                   ActionListener<BulkResponse> actionListener) {
-            this.ingestTookInMillis = ingestTookInMillis;
-            this.itemResponses = itemResponses;
-            this.actionListener = actionListener;
-            this.originalSlots = originalSlots;
-        }
-
-        @Override
-        public void onResponse(BulkResponse response) {
-            BulkItemResponse[] items = response.getItems();
-            for (int i = 0; i < items.length; i++) {
-                itemResponses.add(originalSlots[i], response.getItems()[i]);
-            }
-            actionListener.onResponse(new BulkResponse(
-                    itemResponses.toArray(new BulkItemResponse[itemResponses.size()]),
-                    response.getTook().getMillis(), ingestTookInMillis));
-        }
-
-        @Override
-        public void onFailure(Exception e) {
-            actionListener.onFailure(e);
-        }
-    }
 }