/*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.nio.protocol;
import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.http.ConnectionClosedException;
import org.apache.http.ConnectionReuseStrategy;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.concurrent.BasicFuture;
import org.apache.http.concurrent.FutureCallback;
import org.apache.http.impl.DefaultConnectionReuseStrategy;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.IOControl;
import org.apache.http.nio.NHttpClientConnection;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpCoreContext;
import org.apache.http.protocol.HttpProcessor;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
/**
* Pipelining implementation of {@link org.apache.http.nio.protocol.HttpAsyncClientExchangeHandler}
* that executes a series of pipelined HTTP requests.
*
* @param <T> the result type of request execution.
* @since 4.4
*/
@Pipelined()
public class PipeliningClientExchangeHandler<T> implements HttpAsyncClientExchangeHandler {
private final Queue<HttpAsyncRequestProducer> requestProducerQueue;
private final Queue<HttpAsyncResponseConsumer<T>> responseConsumerQueue;
private final Queue<HttpRequest> requestQueue;
private final Queue<T> resultQueue;
private final BasicFuture<List<T>> future;
private final HttpContext localContext;
private final NHttpClientConnection conn;
private final HttpProcessor httppocessor;
private final ConnectionReuseStrategy connReuseStrategy;
private final AtomicReference<HttpAsyncRequestProducer> requestProducerRef;
private final AtomicReference<HttpAsyncResponseConsumer<T>> responseConsumerRef;
private final AtomicBoolean keepAlive;
private final AtomicBoolean closed;
/**
* Creates new instance of {@code PipeliningClientExchangeHandler}.
*
* @param requestProducers the request producers.
* @param responseConsumers the response consumers.
* @param callback the future callback invoked when the operation is completed.
* @param localContext the local execution context.
* @param conn the actual connection.
* @param httppocessor the HTTP protocol processor.
* @param connReuseStrategy the connection re-use strategy.
*/
public PipeliningClientExchangeHandler(
final List<? extends HttpAsyncRequestProducer> requestProducers,
final List<? extends HttpAsyncResponseConsumer<T>> responseConsumers,
final FutureCallback<List<T>> callback,
final HttpContext localContext,
final NHttpClientConnection conn,
final HttpProcessor httppocessor,
final ConnectionReuseStrategy connReuseStrategy) {
super();
Args.notEmpty(requestProducers, "Request producer list");
Args.notEmpty(responseConsumers, "Response consumer list");
Args.check(requestProducers.size() == responseConsumers.size(),
"Number of request producers does not match that of response consumers");
this.requestProducerQueue = new ConcurrentLinkedQueue<HttpAsyncRequestProducer>(requestProducers);
this.responseConsumerQueue = new ConcurrentLinkedQueue<HttpAsyncResponseConsumer<T>>(responseConsumers);
this.requestQueue = new ConcurrentLinkedQueue<HttpRequest>();
this.resultQueue = new ConcurrentLinkedQueue<T>();
this.future = new BasicFuture<List<T>>(callback);
this.localContext = Args.notNull(localContext, "HTTP context");
this.conn = Args.notNull(conn, "HTTP connection");
this.httppocessor = Args.notNull(httppocessor, "HTTP processor");
this.connReuseStrategy = connReuseStrategy != null ? connReuseStrategy :
DefaultConnectionReuseStrategy.INSTANCE;
this.localContext.setAttribute(HttpCoreContext.HTTP_CONNECTION, this.conn);
this.requestProducerRef = new AtomicReference<HttpAsyncRequestProducer>(null);
this.responseConsumerRef = new AtomicReference<HttpAsyncResponseConsumer<T>>(null);
this.keepAlive = new AtomicBoolean(false);
this.closed = new AtomicBoolean(false);
}
/**
* Creates new instance of {@code PipeliningClientExchangeHandler}.
*
* @param requestProducers the request producers.
* @param responseConsumers the response consumers.
* @param localContext the local execution context.
* @param conn the actual connection.
* @param httppocessor the HTTP protocol processor.
*/
public PipeliningClientExchangeHandler(
final List<? extends HttpAsyncRequestProducer> requestProducers,
final List<? extends HttpAsyncResponseConsumer<T>> responseConsumers,
final HttpContext localContext,
final NHttpClientConnection conn,
final HttpProcessor httppocessor) {
this(requestProducers, responseConsumers, null, localContext, conn, httppocessor, null);
}
public Future<List<T>> getFuture() {
return this.future;
}
private static void closeQuietly(final Closeable closeable) {
if (closeable != null) {
try {
closeable.close();
} catch (final IOException ex) {
}
}
}
private void releaseResources() {
closeQuietly(this.requestProducerRef.getAndSet(null));
closeQuietly(this.responseConsumerRef.getAndSet(null));
while (!this.requestProducerQueue.isEmpty()) {
closeQuietly(this.requestProducerQueue.remove());
}
while (!this.responseConsumerQueue.isEmpty()) {
closeQuietly(this.responseConsumerQueue.remove());
}
this.requestQueue.clear();
this.resultQueue.clear();
}
@Override
public void close() throws IOException {
if (this.closed.compareAndSet(false, true)) {
releaseResources();
if (!this.future.isDone()) {
this.future.cancel();
}
}
}
@Override
public HttpRequest generateRequest() throws IOException, HttpException {
Asserts.check(this.requestProducerRef.get() == null, "Inconsistent state: request producer is not null");
final HttpAsyncRequestProducer requestProducer = this.requestProducerQueue.poll();
if (requestProducer == null) {
return null;
}
this.requestProducerRef.set(requestProducer);
final HttpRequest request = requestProducer.generateRequest();
this.httppocessor.process(request, this.localContext);
this.requestQueue.add(request);
return request;
}
@Override
public void produceContent(
final ContentEncoder encoder, final IOControl ioctrl) throws IOException {
final HttpAsyncRequestProducer requestProducer = this.requestProducerRef.get();
Asserts.check(requestProducer != null, "Inconsistent state: request producer is null");
requestProducer.produceContent(encoder, ioctrl);
}
@Override
public void requestCompleted() {
final HttpAsyncRequestProducer requestProducer = this.requestProducerRef.getAndSet(null);
Asserts.check(requestProducer != null, "Inconsistent state: request producer is null");
requestProducer.requestCompleted(this.localContext);
}
@Override
public void responseReceived(final HttpResponse response) throws IOException, HttpException {
Asserts.check(this.responseConsumerRef.get() == null, "Inconsistent state: response consumer is not null");
final HttpAsyncResponseConsumer<T> responseConsumer = this.responseConsumerQueue.poll();
Asserts.check(responseConsumer != null, "Inconsistent state: response consumer queue is empty");
this.responseConsumerRef.set(responseConsumer);
final HttpRequest request = this.requestQueue.poll();
Asserts.check(request != null, "Inconsistent state: request queue is empty");
this.localContext.setAttribute(HttpCoreContext.HTTP_REQUEST, request);
this.localContext.setAttribute(HttpCoreContext.HTTP_RESPONSE, response);
this.httppocessor.process(response, this.localContext);
responseConsumer.responseReceived(response);
this.keepAlive.set(this.connReuseStrategy.keepAlive(response, this.localContext));
}
@Override
public void consumeContent(
final ContentDecoder decoder, final IOControl ioctrl) throws IOException {
final HttpAsyncResponseConsumer<T> responseConsumer = this.responseConsumerRef.get();
Asserts.check(responseConsumer != null, "Inconsistent state: response consumer is null");
responseConsumer.consumeContent(decoder, ioctrl);
}
@Override
public void responseCompleted() throws IOException {
final HttpAsyncResponseConsumer<T> responseConsumer = this.responseConsumerRef.getAndSet(null);
Asserts.check(responseConsumer != null, "Inconsistent state: response consumer is null");
try {
if (!this.keepAlive.get()) {
this.conn.close();
}
responseConsumer.responseCompleted(this.localContext);
final T result = responseConsumer.getResult();
final Exception ex = responseConsumer.getException();
if (result != null) {
this.resultQueue.add(result);
} else {
this.future.failed(ex);
this.conn.shutdown();
}
if (!conn.isOpen()) {
if (this.closed.compareAndSet(false, true)) {
releaseResources();
}
}
if (!this.future.isDone() && this.responseConsumerQueue.isEmpty()) {
this.future.completed(new ArrayList<T>(this.resultQueue));
this.resultQueue.clear();
}
} catch (final RuntimeException ex) {
failed(ex);
throw ex;
}
}
@Override
public void inputTerminated() {
failed(new ConnectionClosedException("Connection closed"));
}
@Override
public void failed(final Exception ex) {
if (this.closed.compareAndSet(false, true)) {
try {
final HttpAsyncRequestProducer requestProducer = this.requestProducerRef.get();
if (requestProducer != null) {
requestProducer.failed(ex);
}
final HttpAsyncResponseConsumer<T> responseConsumer = this.responseConsumerRef.get();
if (responseConsumer != null) {
responseConsumer.failed(ex);
}
} finally {
try {
this.future.failed(ex);
} finally {
releaseResources();
}
}
}
}
@Override
public boolean cancel() {
if (this.closed.compareAndSet(false, true)) {
try {
try {
final HttpAsyncResponseConsumer<T> responseConsumer = this.responseConsumerRef.get();
return responseConsumer != null && responseConsumer.cancel();
} finally {
this.future.cancel();
}
} finally {
releaseResources();
}
}
return false;
}
@Override
public boolean isDone() {
return this.future.isDone();
}
}