Github user satishd commented on a diff in the pull request:
https://github.com/apache/storm/pull/827#discussion_r45037532
--- Diff:
external/storm-cassandra/src/main/java/org/apache/storm/cassandra/executor/AsyncExecutor.java
---
@@ -0,0 +1,152 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.storm.cassandra.executor;
+
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.datastax.driver.core.Statement;
+import com.google.common.util.concurrent.*;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Service to asynchronously executes cassandra statements.
+ */
+public class AsyncExecutor<T> implements Serializable {
+
+ private final static Logger LOG =
LoggerFactory.getLogger(AsyncExecutor.class);
+
+ protected Session session;
+
+ protected ExecutorService executorService;
+
+ protected AsyncResultHandler<T> handler;
+
+ private Map<SettableFuture<T>, Boolean> pending = new
ConcurrentHashMap<>( );
+
+ /**
+ * Creates a new {@link AsyncExecutor} instance.
+ */
+ protected AsyncExecutor(Session session, AsyncResultHandler<T>
handler) {
+ this(session, newSingleThreadExecutor(), handler);
+ }
+
+ /**
+ * Creates a new {@link AsyncExecutor} instance.
+ *
+ * @param session The cassandra session.
+ * @param executorService The executor service responsible to execute
handler.
+ */
+ private AsyncExecutor(Session session, ExecutorService
executorService, AsyncResultHandler<T> handler) {
+ this.session = session;
+ this.executorService = executorService;
+ this.handler = handler;
+ }
+
+ protected static ExecutorService newSingleThreadExecutor() {
+ return Executors.newSingleThreadExecutor(new
ThreadFactoryBuilder().setNameFormat("cassandra-async-handler-%d").build());
+ }
+
+ /**
+ * Asynchronously executes all statements associated to the specified
input. The input will be passed to
+ * the {@link #handler} once all queries succeed or failed.
+ */
+ public List<SettableFuture<T>> execAsync(List<Statement> statements,
final T input) {
+
+ List<SettableFuture<T>> settableFutures = new
ArrayList<>(statements.size());
+
+ for(Statement s : statements)
+ settableFutures.add(execAsync(s, input,
AsyncResultHandler.NO_OP_HANDLER));
+
+ ListenableFuture<List<T>> allAsList =
Futures.allAsList(settableFutures);
+ Futures.addCallback(allAsList, new FutureCallback<List<T>>(){
+ @Override
+ public void onSuccess(List<T> inputs) {
+ handler.success(input);
+ }
+
+ @Override
+ public void onFailure(Throwable t) {
+ handler.failure(t, input);
+ }
+ }, executorService);
+ return settableFutures;
+ }
+
+ /**
+ * Asynchronously executes the specified batch statement. Inputs will
be passed to
+ * the {@link #handler} once query succeed or failed.
+ */
+ public SettableFuture<T> execAsync(final Statement statement, final T
inputs) {
+ return execAsync(statement, inputs, handler);
+ }
+ /**
+ * Asynchronously executes the specified batch statement. Inputs will
be passed to
+ * the {@link #handler} once query succeed or failed.
+ */
+ public SettableFuture<T> execAsync(final Statement statement, final T
inputs, final AsyncResultHandler<T> handler) {
+ final SettableFuture<T> settableFuture = SettableFuture.create();
+ pending.put(settableFuture, true);
+ ResultSetFuture future = session.executeAsync(statement);
+ Futures.addCallback(future, new FutureCallback<ResultSet>() {
+ public void release() {
+ pending.remove(settableFuture);
+ }
+
+ @Override
+ public void onSuccess(ResultSet result) {
+ release();
+ settableFuture.set(inputs);
+ handler.success(inputs);
+ }
+
+ @Override
+ public void onFailure(Throwable t) {
+ LOG.error(String.format("Failed to execute statement '%s'
", statement), t);
+ release();
+ settableFuture.setException(t);
+ handler.failure(t, inputs);
+ }
+ }, executorService);
+ return settableFuture;
+ }
+
+ /**
+ * Returns the number of currently executed tasks which are not yet
completed.
+ */
+ public int getPendingExec( ) {
--- End diff --
Rename to getPendingTasksSize()
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