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/*
 * 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.seda;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.ExecutorService;

import org.apache.camel.AsyncEndpoint;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.Category;
import org.apache.camel.Component;
import org.apache.camel.Consumer;
import org.apache.camel.Exchange;
import org.apache.camel.MultipleConsumersSupport;
import org.apache.camel.PollingConsumer;
import org.apache.camel.Processor;
import org.apache.camel.Producer;
import org.apache.camel.WaitForTaskToComplete;
import org.apache.camel.api.management.ManagedAttribute;
import org.apache.camel.api.management.ManagedOperation;
import org.apache.camel.api.management.ManagedResource;
import org.apache.camel.spi.BrowsableEndpoint;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.UriEndpoint;
import org.apache.camel.spi.UriParam;
import org.apache.camel.spi.UriPath;
import org.apache.camel.support.DefaultEndpoint;
import org.apache.camel.support.PluginHelper;
import org.apache.camel.support.service.ServiceHelper;
import org.apache.camel.util.URISupport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Asynchronously call another endpoint from any Camel Context in the same JVM.
 */
@ManagedResource(description = "Managed SedaEndpoint")
@UriEndpoint(firstVersion = "1.1.0", scheme = "seda", title = "SEDA", syntax = "seda:name",
             category = { Category.CORE, Category.MESSAGING })
public class SedaEndpoint extends DefaultEndpoint implements AsyncEndpoint, BrowsableEndpoint, MultipleConsumersSupport {

    private static final Logger LOG = LoggerFactory.getLogger(SedaEndpoint.class);

    private final Set producers = new CopyOnWriteArraySet<>();
    private final Set consumers = new CopyOnWriteArraySet<>();
    private volatile AsyncProcessor consumerMulticastProcessor;
    private volatile boolean multicastStarted;
    private volatile ExecutorService multicastExecutor;

    @UriPath(description = "Name of queue")
    @Metadata(required = true)
    private String name;
    @UriParam(label = "advanced", description = "Define the queue instance which will be used by the endpoint")
    private BlockingQueue queue;
    @UriParam(defaultValue = "" + SedaConstants.QUEUE_SIZE)
    private int size = SedaConstants.QUEUE_SIZE;

    @UriParam(label = "consumer", defaultValue = "1")
    private int concurrentConsumers = 1;
    @UriParam(label = "consumer,advanced", defaultValue = "true")
    private boolean limitConcurrentConsumers = true;
    @UriParam(label = "consumer,advanced")
    private boolean multipleConsumers;
    @UriParam(label = "consumer,advanced")
    private boolean purgeWhenStopping;
    @UriParam(label = "consumer,advanced", defaultValue = "1000")
    private int pollTimeout = 1000;

    @UriParam(label = "producer", defaultValue = "IfReplyExpected")
    private WaitForTaskToComplete waitForTaskToComplete = WaitForTaskToComplete.IfReplyExpected;
    @UriParam(label = "producer", defaultValue = "30000", javaType = "java.time.Duration")
    private long timeout = 30000;
    @UriParam(label = "producer", javaType = "java.time.Duration")
    private long offerTimeout;
    @UriParam(label = "producer")
    private boolean blockWhenFull;
    @UriParam(label = "producer")
    private boolean discardWhenFull;
    @UriParam(label = "producer")
    private boolean failIfNoConsumers;
    @UriParam(label = "producer")
    private boolean discardIfNoConsumers;

    private BlockingQueueFactory queueFactory;
    private volatile QueueReference ref;

    public SedaEndpoint() {
        queueFactory = new LinkedBlockingQueueFactory<>();
    }

    public SedaEndpoint(String endpointUri, Component component, BlockingQueue queue) {
        this(endpointUri, component, queue, 1);
    }

    public SedaEndpoint(String endpointUri, Component component, BlockingQueue queue, int concurrentConsumers) {
        this(endpointUri, component, concurrentConsumers);
        this.queue = queue;
        if (queue != null) {
            this.size = queue.remainingCapacity();
        }
        queueFactory = new LinkedBlockingQueueFactory<>();
        getComponent().registerQueue(this, queue);
    }

    public SedaEndpoint(String endpointUri, Component component, BlockingQueueFactory queueFactory,
                        int concurrentConsumers) {
        this(endpointUri, component, concurrentConsumers);
        this.queueFactory = queueFactory;
    }

    private SedaEndpoint(String endpointUri, Component component, int concurrentConsumers) {
        super(endpointUri, component);
        this.concurrentConsumers = concurrentConsumers;
    }

    @Override
    public SedaComponent getComponent() {
        return (SedaComponent) super.getComponent();
    }

    @Override
    public Producer createProducer() throws Exception {
        return new SedaProducer(
                this, getWaitForTaskToComplete(), getTimeout(),
                isBlockWhenFull(), isDiscardWhenFull(), getOfferTimeout());
    }

    @Override
    public Consumer createConsumer(Processor processor) throws Exception {
        if (getComponent() != null) {
            // all consumers must match having the same multipleConsumers options
            String key = getComponent().getQueueKey(getEndpointUri());
            QueueReference ref = getComponent().getQueueReference(key);
            if (ref != null && ref.getMultipleConsumers() != isMultipleConsumers()) {
                // there is already a multiple consumers, so make sure they matches
                throw new IllegalArgumentException(
                        "Cannot use existing queue " + key + " as the existing queue multiple consumers "
                                                   + ref.getMultipleConsumers() + " does not match given multiple consumers "
                                                   + multipleConsumers);
            }
        }

        Consumer answer = createNewConsumer(processor);
        configureConsumer(answer);
        return answer;
    }

    protected SedaConsumer createNewConsumer(Processor processor) {
        return new SedaConsumer(this, processor);
    }

    @Override
    public PollingConsumer createPollingConsumer() throws Exception {
        SedaPollingConsumer answer = new SedaPollingConsumer(this);
        configureConsumer(answer);
        return answer;
    }

    public synchronized BlockingQueue getQueue() {
        if (queue == null) {
            // prefer to lookup queue from component, so if this endpoint is re-created or re-started
            // then the existing queue from the component can be used, so new producers and consumers
            // can use the already existing queue referenced from the component
            if (getComponent() != null) {
                // use null to indicate default size (= use what the existing queue has been configured with)
                Integer size = (getSize() == Integer.MAX_VALUE || getSize() == SedaConstants.QUEUE_SIZE) ? null : getSize();
                QueueReference ref = getComponent().getOrCreateQueue(this, size, isMultipleConsumers(), queueFactory);
                queue = ref.getQueue();
                String key = getComponent().getQueueKey(getEndpointUri());
                LOG.debug("Endpoint {} is using shared queue: {} with size: {}", this, key,
                        ref.getSize() != null ? ref.getSize() : Integer.MAX_VALUE);
                // and set the size we are using
                if (ref.getSize() != null) {
                    setSize(ref.getSize());
                }
            } else {
                // fallback and create queue (as this endpoint has no component)
                queue = createQueue();
                LOG.debug("Endpoint {} is using queue: {} with size: {}", this, getEndpointUri(), getSize());
            }
        }
        return queue;
    }

    protected BlockingQueue createQueue() {
        if (size > 0) {
            return queueFactory.create(size);
        } else {
            return queueFactory.create();
        }
    }

    /**
     * Gets the {@link QueueReference} for this endpoint.
     *
     * @return the reference, or null if no queue reference exists.
     */
    public QueueReference getQueueReference() {
        if (ref == null || ref.getCount() == 0) {
            ref = tryQueueRefInit();
        }

        return ref;
    }

    private QueueReference tryQueueRefInit() {
        final SedaComponent component = getComponent();
        if (component != null) {
            final String key = component.getQueueKey(getEndpointUri());
            return component.getQueueReference(key);
        }

        return null;
    }

    protected synchronized AsyncProcessor getConsumerMulticastProcessor() {
        if (!multicastStarted && consumerMulticastProcessor != null) {
            // only start it on-demand to avoid starting it during stopping
            ServiceHelper.startService(consumerMulticastProcessor);
            multicastStarted = true;
        }
        return consumerMulticastProcessor;
    }

    protected synchronized void updateMulticastProcessor() throws Exception {
        // only needed if we support multiple consumers
        if (!isMultipleConsumersSupported()) {
            return;
        }

        // stop old before we create a new
        if (consumerMulticastProcessor != null) {
            ServiceHelper.stopService(consumerMulticastProcessor);
            consumerMulticastProcessor = null;
        }

        int size = getConsumers().size();
        if (size >= 1) {
            if (multicastExecutor == null) {
                // create multicast executor as we need it when we have more than 1 processor
                multicastExecutor = getCamelContext().getExecutorServiceManager().newDefaultThreadPool(this,
                        URISupport.sanitizeUri(getEndpointUri()) + "(multicast)");
            }
            // create list of consumers to multicast to
            List processors = new ArrayList<>(size);
            for (SedaConsumer consumer : getConsumers()) {
                processors.add(consumer.getProcessor());
            }
            // create multicast processor
            multicastStarted = false;

            consumerMulticastProcessor = (AsyncProcessor) PluginHelper.getProcessorFactory(getCamelContext())
                    .createProcessor(getCamelContext(), "MulticastProcessor",
                            new Object[] { processors, multicastExecutor, false });
        }
    }

    /**
     * Define the queue instance which will be used by the endpoint.
     * 

* This option is only for rare use-cases where you want to use a custom queue instance. */ public void setQueue(BlockingQueue queue) { this.queue = queue; this.size = queue.remainingCapacity(); } @ManagedAttribute(description = "Queue max capacity") public int getSize() { return size; } /** * The maximum capacity of the SEDA queue (i.e., the number of messages it can hold). Will by default use the * defaultSize set on the SEDA component. */ public void setSize(int size) { this.size = size; } @ManagedAttribute(description = "Current queue size") public int getCurrentQueueSize() { return queue.size(); } /** * Whether a thread that sends messages to a full SEDA queue will block until the queue's capacity is no longer * exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the * calling thread will instead block and wait until the message can be accepted. */ public void setBlockWhenFull(boolean blockWhenFull) { this.blockWhenFull = blockWhenFull; } @ManagedAttribute(description = "Whether the caller will block sending to a full queue") public boolean isBlockWhenFull() { return blockWhenFull; } /** * Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be * thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and * continue, meaning that the message was not sent to the SEDA queue. */ public void setDiscardWhenFull(boolean discardWhenFull) { this.discardWhenFull = discardWhenFull; } @ManagedAttribute(description = "Whether the caller will discard sending to a full queue") public boolean isDiscardWhenFull() { return discardWhenFull; } /** * Number of concurrent threads processing exchanges. */ public void setConcurrentConsumers(int concurrentConsumers) { this.concurrentConsumers = concurrentConsumers; } @ManagedAttribute(description = "Number of concurrent consumers") public int getConcurrentConsumers() { return concurrentConsumers; } @ManagedAttribute public boolean isLimitConcurrentConsumers() { return limitConcurrentConsumers; } /** * Whether to limit the number of concurrentConsumers to the maximum of 500. By default, an exception will be thrown * if an endpoint is configured with a greater number. You can disable that check by turning this option off. */ public void setLimitConcurrentConsumers(boolean limitConcurrentConsumers) { this.limitConcurrentConsumers = limitConcurrentConsumers; } public WaitForTaskToComplete getWaitForTaskToComplete() { return waitForTaskToComplete; } /** * Option to specify whether the caller should wait for the async task to complete or not before continuing. The * following three options are supported: Always, Never or IfReplyExpected. The first two values are * self-explanatory. The last value, IfReplyExpected, will only wait if the message is Request Reply based. The * default option is IfReplyExpected. */ public void setWaitForTaskToComplete(WaitForTaskToComplete waitForTaskToComplete) { this.waitForTaskToComplete = waitForTaskToComplete; } @ManagedAttribute public long getTimeout() { return timeout; } /** * Timeout (in milliseconds) before a SEDA producer will stop waiting for an asynchronous task to complete. You can * disable timeout by using 0 or a negative value. */ public void setTimeout(long timeout) { this.timeout = timeout; } @ManagedAttribute public long getOfferTimeout() { return offerTimeout; } /** * Offer timeout (in milliseconds) can be added to the block case when queue is full. You can disable timeout by * using 0 or a negative value. */ public void setOfferTimeout(long offerTimeout) { this.offerTimeout = offerTimeout; } @ManagedAttribute public boolean isFailIfNoConsumers() { return failIfNoConsumers; } /** * Whether the producer should fail by throwing an exception, when sending to a queue with no active consumers. *

* Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same * time. */ public void setFailIfNoConsumers(boolean failIfNoConsumers) { this.failIfNoConsumers = failIfNoConsumers; } @ManagedAttribute public boolean isDiscardIfNoConsumers() { return discardIfNoConsumers; } /** * Whether the producer should discard the message (do not add the message to the queue), when sending to a queue * with no active consumers. *

* Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same * time. */ public void setDiscardIfNoConsumers(boolean discardIfNoConsumers) { this.discardIfNoConsumers = discardIfNoConsumers; } @ManagedAttribute public boolean isMultipleConsumers() { return multipleConsumers; } /** * Specifies whether multiple consumers are allowed. If enabled, you can use SEDA for Publish-Subscribe messaging. * That is, you can send a message to the SEDA queue and have each consumer receive a copy of the message. When * enabled, this option should be specified on every consumer endpoint. */ public void setMultipleConsumers(boolean multipleConsumers) { this.multipleConsumers = multipleConsumers; } @ManagedAttribute public int getPollTimeout() { return pollTimeout; } /** * The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is * allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown. */ public void setPollTimeout(int pollTimeout) { this.pollTimeout = pollTimeout; } @ManagedAttribute public boolean isPurgeWhenStopping() { return purgeWhenStopping; } /** * Whether to purge the task queue when stopping the consumer/route. This allows to stop faster, as any pending * messages on the queue is discarded. */ public void setPurgeWhenStopping(boolean purgeWhenStopping) { this.purgeWhenStopping = purgeWhenStopping; } /** * Returns the current pending exchanges */ @Override public List getExchanges() { return new ArrayList<>(getQueue()); } @Override @ManagedAttribute public boolean isMultipleConsumersSupported() { return isMultipleConsumers(); } /** * Purges the queue */ @ManagedOperation(description = "Purges the seda queue") public void purgeQueue() { LOG.debug("Purging queue with {} exchanges", queue.size()); queue.clear(); } /** * Returns the current active consumers on this endpoint */ public Set getConsumers() { return consumers; } /** * Returns the current active producers on this endpoint */ public Set getProducers() { return new HashSet<>(producers); } void onStarted(SedaProducer producer) { producers.add(producer); } void onStopped(SedaProducer producer) { producers.remove(producer); } void onStarted(SedaConsumer consumer) throws Exception { consumers.add(consumer); if (isMultipleConsumers()) { updateMulticastProcessor(); } } void onStopped(SedaConsumer consumer) throws Exception { consumers.remove(consumer); if (isMultipleConsumers()) { updateMulticastProcessor(); } } public boolean hasConsumers() { return !this.consumers.isEmpty(); } @Override protected void doInit() throws Exception { super.doInit(); if (discardWhenFull && blockWhenFull) { throw new IllegalArgumentException( "Cannot enable both discardWhenFull=true and blockWhenFull=true." + " You can only either discard or block when full."); } } @Override protected void doStart() throws Exception { super.doStart(); // force creating queue when starting if (queue == null) { queue = getQueue(); } ref = tryQueueRefInit(); } @Override public void stop() { if (getConsumers().isEmpty()) { super.stop(); } else { LOG.debug("There is still active consumers."); } ref = null; } @Override public void shutdown() { if (isShutdown()) { LOG.trace("Service already shut down"); return; } // notify component we are shutting down this endpoint if (getComponent() != null) { getComponent().onShutdownEndpoint(this); } if (getConsumers().isEmpty()) { super.shutdown(); } else { LOG.debug("There is still active consumers."); } } @Override protected void doShutdown() throws Exception { // shutdown thread pool if it was in use if (multicastExecutor != null) { getCamelContext().getExecutorServiceManager().shutdownNow(multicastExecutor); multicastExecutor = null; } // clear queue, as we are shutdown, so if re-created then the queue must be updated queue = null; ref = null; } }





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