org.springframework.integration.channel

Class QueueChannel

java.lang.Object

org.springframework.integration.context.IntegrationObjectSupport

org.springframework.integration.channel.AbstractMessageChannel

org.springframework.integration.channel.AbstractPollableChannel

org.springframework.integration.channel.QueueChannel

All Implemented Interfaces:

Aware, BeanFactoryAware, BeanNameAware, InitializingBean, ApplicationContextAware, ChannelInterceptorAware, QueueChannelOperations, TrackableComponent, NamedComponent, MessageChannel, PollableChannel

Direct Known Subclasses:

PriorityChannel, RendezvousChannel

public class QueueChannel
extends AbstractPollableChannel
implements QueueChannelOperations

Simple implementation of a message channel. Each Message is placed in a BlockingQueue whose capacity may be specified upon construction. The capacity must be a positive integer value. For a zero-capacity version based upon a SynchronousQueue, consider the RendezvousChannel.

Author:

Mark Fisher, Oleg Zhurakousky, Gary Russell

Nested Class Summary

Nested classes/interfaces inherited from class org.springframework.integration.channel.AbstractMessageChannel

AbstractMessageChannel.ChannelInterceptorList

Field Summary

Fields inherited from class org.springframework.integration.context.IntegrationObjectSupport

logger

Fields inherited from interface org.springframework.messaging.MessageChannel

INDEFINITE_TIMEOUT

Constructor Summary

Constructors

Constructor and Description
QueueChannel() Create a channel with "unbounded" queue capacity.
QueueChannel(BlockingQueue<Message<?>> queue) Create a channel with the specified queue.
QueueChannel(int capacity) Create a channel with the specified queue capacity.

Method Summary

Methods

Modifier and Type	Method and Description
List<Message<?>>	clear() Remove all Messages from this channel.
protected Message<?>	doReceive(long timeout) Subclasses must implement this method.
protected boolean	doSend(Message<?> message, long timeout) Subclasses must implement this method.
int	getQueueSize()
int	getRemainingCapacity()
List<Message<?>>	purge(MessageSelector selector) Remove any Messages that are not accepted by the provided selector.

Methods inherited from class org.springframework.integration.channel.AbstractPollableChannel

receive, receive

Methods inherited from class org.springframework.integration.channel.AbstractMessageChannel

addInterceptor, addInterceptor, getChannelInterceptors, getComponentType, getFullChannelName, getInterceptors, onInit, send, send, setConversionService, setDatatypes, setInterceptors, setMessageConverter, setShouldTrack

Methods inherited from class org.springframework.integration.context.IntegrationObjectSupport

afterPropertiesSet, getApplicationContextId, getBeanFactory, getComponentName, getConversionService, getIntegrationProperties, getIntegrationProperty, getMessageBuilderFactory, getTaskScheduler, setApplicationContext, setBeanFactory, setBeanName, setComponentName, setMessageBuilderFactory, setTaskScheduler, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.springframework.messaging.MessageChannel

send, send

Methods inherited from interface org.springframework.integration.support.context.NamedComponent

getComponentName

Constructor Detail

QueueChannel

public QueueChannel(BlockingQueue<Message<?>> queue)

Create a channel with the specified queue.

Parameters:

queue - The queue.

QueueChannel

public QueueChannel(int capacity)

Create a channel with the specified queue capacity.

Parameters:

capacity - The capacity.

QueueChannel

public QueueChannel()

Create a channel with "unbounded" queue capacity. The actual capacity value is Integer.MAX_VALUE. Note that a bounded queue is recommended, since an unbounded queue may lead to OutOfMemoryErrors.

Method Detail

doSend

protected boolean doSend(Message<?> message,
             long timeout)

Description copied from class: AbstractMessageChannel

Subclasses must implement this method. A non-negative timeout indicates how long to wait if the channel is at capacity (if the value is 0, it must return immediately with or without success). A negative timeout value indicates that the method should block until either the message is accepted or the blocking thread is interrupted.

Specified by:

doSend in class AbstractMessageChannel

Parameters:

message - The message.

timeout - The timeout.

Returns:

true if the send was successful.

doReceive

protected Message<?> doReceive(long timeout)

Description copied from class: AbstractPollableChannel

Subclasses must implement this method. A non-negative timeout indicates how long to wait if the channel is empty (if the value is 0, it must return immediately with or without success). A negative timeout value indicates that the method should block until either a message is available or the blocking thread is interrupted.

Specified by:

doReceive in class AbstractPollableChannel

Parameters:

timeout - The timeout.

Returns:

The message, or null.

clear

public List<Message<?>> clear()

Description copied from interface: QueueChannelOperations

Remove all Messages from this channel.

Specified by:

clear in interface QueueChannelOperations

Returns:

The messages that were removed.

purge

public List<Message<?>> purge(MessageSelector selector)

Description copied from interface: QueueChannelOperations

Remove any Messages that are not accepted by the provided selector.

Specified by:

purge in interface QueueChannelOperations

Parameters:

selector - The message selector.

Returns:

The list of messages that were purged.

getQueueSize

public int getQueueSize()

Specified by:

getQueueSize in interface QueueChannelOperations

Returns:

The current number of queued Messages in this channel.

getRemainingCapacity

public int getRemainingCapacity()

Specified by:

getRemainingCapacity in interface QueueChannelOperations

Returns:

The remaining capacity of this channel.