org.eclipse.jetty.client.HttpExchange Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.client;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicMarkableReference;
import org.eclipse.jetty.client.api.Request;
import org.eclipse.jetty.client.api.Response;
import org.eclipse.jetty.client.api.Result;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
public class HttpExchange
{
private static final Logger LOG = Log.getLogger(HttpExchange.class);
private final AtomicInteger complete = new AtomicInteger();
private final CountDownLatch terminate = new CountDownLatch(2);
private final HttpConversation conversation;
private final HttpDestination destination;
private final Request request;
private final List listeners;
private final HttpResponse response;
private volatile HttpConnection connection;
private volatile Throwable requestFailure;
private volatile Throwable responseFailure;
public HttpExchange(HttpConversation conversation, HttpDestination destination, Request request, List listeners)
{
this.conversation = conversation;
this.destination = destination;
this.request = request;
this.listeners = listeners;
this.response = new HttpResponse(request, listeners);
conversation.getExchanges().offer(this);
conversation.updateResponseListeners(null);
}
public HttpConversation getConversation()
{
return conversation;
}
public Request getRequest()
{
return request;
}
public Throwable getRequestFailure()
{
return requestFailure;
}
public List getResponseListeners()
{
return listeners;
}
public HttpResponse getResponse()
{
return response;
}
public Throwable getResponseFailure()
{
return responseFailure;
}
public void setConnection(HttpConnection connection)
{
this.connection = connection;
}
public AtomicMarkableReference requestComplete(Throwable failure)
{
int requestSuccess = 0b0011;
int requestFailure = 0b0001;
return complete(failure == null ? requestSuccess : requestFailure, failure);
}
public AtomicMarkableReference responseComplete(Throwable failure)
{
if (failure == null)
{
int responseSuccess = 0b1100;
return complete(responseSuccess, failure);
}
else
{
proceed(false);
int responseFailure = 0b0100;
return complete(responseFailure, failure);
}
}
/**
* This method needs to atomically compute whether this exchange is completed,
* that is both request and responses are completed (either with a success or
* a failure).
*
* Furthermore, this method needs to atomically compute whether the exchange
* has completed successfully (both request and response are successful) or not.
*
* To do this, we use 2 bits for the request (one to indicate completion, one
* to indicate success), and similarly for the response.
* By using {@link AtomicInteger} to atomically sum these codes we can know
* whether the exchange is completed and whether is successful.
*
* @param code the bits representing the status code for either the request or the response
* @param failure the failure - if any - associated with the status code for either the request or the response
* @return an AtomicMarkableReference holding whether the operation modified the
* completion status and the {@link Result} - if any - associated with the status
*/
private AtomicMarkableReference complete(int code, Throwable failure)
{
Result result = null;
boolean modified = false;
int current;
while (true)
{
current = complete.get();
boolean updateable = (current & code) == 0;
if (updateable)
{
int candidate = current | code;
if (!complete.compareAndSet(current, candidate))
continue;
current = candidate;
modified = true;
if ((code & 0b01) == 0b01)
requestFailure = failure;
else
responseFailure = failure;
LOG.debug("{} updated", this);
}
break;
}
int completed = 0b0101;
if ((current & completed) == completed)
{
if (modified)
{
// Request and response completed
LOG.debug("{} complete", this);
conversation.complete();
}
result = new Result(getRequest(), getRequestFailure(), getResponse(), getResponseFailure());
}
return new AtomicMarkableReference<>(result, modified);
}
public boolean abort(Throwable cause)
{
if (destination.remove(this))
{
destination.abort(this, cause);
LOG.debug("Aborted while queued {}: {}", this, cause);
return true;
}
else
{
HttpConnection connection = this.connection;
// If there is no connection, this exchange is already completed
if (connection == null)
return false;
boolean aborted = connection.abort(cause);
LOG.debug("Aborted while active ({}) {}: {}", aborted, this, cause);
return aborted;
}
}
public void resetResponse(boolean success)
{
int responseSuccess = 0b1100;
int responseFailure = 0b0100;
int code = success ? responseSuccess : responseFailure;
complete.addAndGet(-code);
}
public void proceed(boolean proceed)
{
HttpConnection connection = this.connection;
if (connection != null)
connection.proceed(proceed);
}
public void terminateRequest()
{
terminate.countDown();
}
public void terminateResponse()
{
terminate.countDown();
}
public void awaitTermination()
{
try
{
terminate.await();
}
catch (InterruptedException x)
{
LOG.ignore(x);
}
}
@Override
public String toString()
{
String padding = "0000";
String status = Integer.toBinaryString(complete.get());
return String.format("%s@%x status=%s%s",
HttpExchange.class.getSimpleName(),
hashCode(),
padding.substring(status.length()),
status);
}
}