Package 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, DisposableBean, InitializingBean, ApplicationContextAware, ExecutorChannelInterceptorAware, QueueChannelOperations, ExpressionCapable, IntegrationPattern, NamedComponent, IntegrationManagement, TrackableComponent, MessageChannel, PollableChannel, InterceptableChannel

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, Artem Bilan

Nested Class Summary

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

AbstractMessageChannel.ChannelInterceptorList

Nested classes/interfaces inherited from interface org.springframework.integration.support.management.IntegrationManagement

IntegrationManagement.ManagementOverrides

Field Summary

Fields

Modifier and Type	Field	Description
protected final Semaphore	queueSemaphore

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

interceptors, meters

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

EXPRESSION_PARSER, logger

Fields inherited from interface org.springframework.integration.support.management.IntegrationManagement

METER_PREFIX, RECEIVE_COUNTER_NAME, SEND_TIMER_NAME

Fields inherited from interface org.springframework.messaging.MessageChannel

INDEFINITE_TIMEOUT

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
List<Message<?>>	clear()	Remove all Messages from this channel.
void	destroy()
protected Message<?>	doReceive(long timeout)	Subclasses must implement this method.
protected boolean	doSend(Message<?> message, long timeout)	Subclasses must implement this method.
int	getQueueSize()	Obtain the current number of queued Messages in this channel.
int	getRemainingCapacity()	Obtain the remaining capacity of this channel.
List<Message<?>>	purge(MessageSelector selector)	Remove any Messages that are not accepted by the provided selector.
void	registerMetricsCaptor(MetricsCaptor metricsCaptor)	Inject a MetricsCaptor.

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

addInterceptor, addInterceptor, getIntegrationPatternType, hasExecutorInterceptors, receive, receive, removeInterceptor, removeInterceptor, setInterceptors

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

getComponentType, getFullChannelName, getIChannelInterceptorList, getInterceptors, getMetricsCaptor, getOverrides, isLoggingEnabled, isObserved, onInit, registerObservationRegistry, send, send, setDatatypes, setLoggingEnabled, setMessageConverter, setObservationConvention, setShouldTrack

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

afterPropertiesSet, extractTypeIfPossible, generateId, getApplicationContext, getApplicationContextId, getBeanDescription, getBeanFactory, getBeanName, getChannelResolver, getComponentName, getConversionService, getExpression, getIntegrationProperties, getMessageBuilderFactory, getTaskScheduler, isInitialized, setApplicationContext, setBeanFactory, setBeanName, setChannelResolver, setComponentName, setConversionService, setMessageBuilderFactory, setPrimaryExpression, 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.integration.support.management.IntegrationManagement

getManagedName, getManagedType, getThisAs, setManagedName, setManagedType

Methods inherited from interface org.springframework.messaging.support.InterceptableChannel

getInterceptors

Methods inherited from interface org.springframework.messaging.MessageChannel

send, send

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

getBeanName, getComponentName

Field Details

queueSemaphore

protected final Semaphore queueSemaphore

Constructor Details

QueueChannel

public QueueChannel(Queue<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 Details

registerMetricsCaptor

public void registerMetricsCaptor(MetricsCaptor metricsCaptor)

Description copied from interface: IntegrationManagement

Inject a MetricsCaptor. Ignored if ObservationRegistry is provided.

Specified by:

registerMetricsCaptor in interface IntegrationManagement

Overrides:

registerMetricsCaptor in class AbstractMessageChannel

Parameters:

metricsCaptor - the captor.

See Also:

• IntegrationManagement.registerObservationRegistry(ObservationRegistry)

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

@Nullable
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(@Nullable
 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()

Description copied from interface: QueueChannelOperations

Obtain the current number of queued Messages in this channel.

Specified by:

getQueueSize in interface QueueChannelOperations

Returns:

The current number of queued Messages in this channel.

getRemainingCapacity

public int getRemainingCapacity()

Description copied from interface: QueueChannelOperations

Obtain the remaining capacity of this channel.

Specified by:

getRemainingCapacity in interface QueueChannelOperations

Returns:

The remaining capacity of this channel.

destroy

public void destroy()

Specified by:

destroy in interface DisposableBean

Specified by:

destroy in interface IntegrationManagement

Overrides:

destroy in class AbstractMessageChannel