trunk/components/camel-routebox/src/main/java/org/apache/camel/component/routebox/seda/RouteboxSedaProducer.java

/**
 * 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.camel.component.routebox.seda;

import java.util.Collection;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.apache.camel.AsyncCallback;
import org.apache.camel.Exchange;
import org.apache.camel.ExchangeTimedOutException;
import org.apache.camel.WaitForTaskToComplete;
import org.apache.camel.component.routebox.RouteboxProducer;
import org.apache.camel.impl.DefaultAsyncProducer;
import org.apache.camel.impl.SynchronizationAdapter;
import org.apache.camel.util.ExchangeHelper;

/**
 * @version 
 */
public class RouteboxSedaProducer extends DefaultAsyncProducer implements RouteboxProducer {
    protected final Collection<Exchange> queue;
    private final RouteboxSedaEndpoint endpoint;
    private final WaitForTaskToComplete waitForTaskToComplete;
    private final long timeout;

    public RouteboxSedaProducer(RouteboxSedaEndpoint endpoint, BlockingQueue<Exchange> queue, WaitForTaskToComplete waitForTaskToComplete, long timeout) {
        super(endpoint);
        this.endpoint = endpoint;
        this.queue = queue;
        this.waitForTaskToComplete = waitForTaskToComplete;
        this.timeout = timeout;
    }

    public boolean process(final Exchange exchange, final AsyncCallback callback) {
        // use a new copy of the exchange to route async and handover the on completion to the new copy
        // so its the new copy that performs the on completion callback when its done
        Exchange copy = ExchangeHelper.createCorrelatedCopy(exchange, true);
        // set a new from endpoint to be the seda queue
        copy.setFromEndpoint(endpoint);

        WaitForTaskToComplete wait = waitForTaskToComplete;
        if (exchange.getProperty(Exchange.ASYNC_WAIT) != null) {
            wait = exchange.getProperty(Exchange.ASYNC_WAIT, WaitForTaskToComplete.class);
        }

        if (wait == WaitForTaskToComplete.Always
            || (wait == WaitForTaskToComplete.IfReplyExpected && ExchangeHelper.isOutCapable(exchange))) {

            // latch that waits until we are complete
            final CountDownLatch latch = new CountDownLatch(1);

            // we should wait for the reply so install a on completion so we know when its complete
            copy.addOnCompletion(new SynchronizationAdapter() {
                @Override
                public void onDone(Exchange response) {
                    // check for timeout, which then already would have invoked the latch
                    if (latch.getCount() == 0) {
                        if (log.isTraceEnabled()) {
                            log.trace(this + ". Timeout occurred so response will be ignored: " + (response.hasOut() ? response.getOut() : response.getIn()));
                        }
                        return;
                    } else {
                        if (log.isTraceEnabled()) {
                            log.trace(this + " with response: " + (response.hasOut() ? response.getOut() : response.getIn()));
                        }
                        try {
                            ExchangeHelper.copyResults(exchange, response);
                        } finally {
                            // always ensure latch is triggered
                            latch.countDown();
                        }
                    }
                }

                @Override
                public boolean allowHandover() {
                    return false;
                }

                @Override
                public String toString() {
                    return "onDone at [" + endpoint.getEndpointUri() + "]";
                }
            });

            queue.add(copy);

            if (timeout > 0) {
                if (log.isTraceEnabled()) {
                    log.trace("Waiting for task to complete using timeout (ms): " + timeout + " at [" + endpoint.getEndpointUri() + "]");
                }
                // lets see if we can get the task done before the timeout
                boolean done = false;
                try {
                    done = latch.await(timeout, TimeUnit.MILLISECONDS);
                } catch (InterruptedException e) {
                    // ignore
                }
                if (!done) {
                    exchange.setException(new ExchangeTimedOutException(exchange, timeout));
                    // count down to indicate timeout
                    latch.countDown();
                }
            } else {
                if (log.isTraceEnabled()) {
                    log.trace("Waiting for task to complete (blocking) at [" + endpoint.getEndpointUri() + "]");
                }
                // no timeout then wait until its done
                try {
                    latch.await();
                } catch (InterruptedException e) {
                    // ignore
                }
            }
        } else {
            // no wait, eg its a InOnly then just add to queue and return
            queue.add(copy);
        }

        // we use OnCompletion on the Exchange to callback and wait for the Exchange to be done
        // so we should just signal the callback we are done synchronously
        callback.done(true);
        return true;
    }

    @Override
    protected void doStart() throws Exception {
        super.doStart();
        endpoint.onStarted(this);
    }

    @Override
    protected void doStop() throws Exception {
        endpoint.onStopped(this);
        super.doStop();
    }
}