Package org.apache.camel.processor

Class TotalRequestsThrottler

java.lang.Object

org.apache.camel.support.service.BaseService

org.apache.camel.support.service.ServiceSupport

org.apache.camel.support.AsyncProcessorSupport

org.apache.camel.processor.AbstractThrottler

org.apache.camel.processor.TotalRequestsThrottler

All Implemented Interfaces:

AutoCloseable, org.apache.camel.AsyncProcessor, org.apache.camel.Processor, Throttler, org.apache.camel.Service, org.apache.camel.ShutdownableService, org.apache.camel.spi.HasId, org.apache.camel.spi.IdAware, org.apache.camel.spi.RouteIdAware, org.apache.camel.StatefulService, org.apache.camel.SuspendableService, org.apache.camel.Traceable

public class TotalRequestsThrottler
extends AbstractThrottler

A Throttler will set a limit on the maximum number of message exchanges which can be sent to a processor within a specific time period.

This pattern can be extremely useful if you have some external system which meters access; such as only allowing 100 requests per second; or if huge load can cause a particular system to malfunction or to reduce its throughput you might want to introduce some throttling. This throttle implementation is thread-safe and is therefore safe to be used by multiple concurrent threads in a single route. The throttling mechanism is a DelayQueue with maxRequestsPerPeriod permits on it. Each permit is set to be delayed by timePeriodMillis (except when the throttler is initialized or the throttle rate increased, then there is no delay for those permits). Callers trying to acquire a permit from the DelayQueue will block if necessary. The end result is a rolling window of time. Where from the callers point of view in the last timePeriodMillis no more than maxRequestsPerPeriod have been allowed to be acquired.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.camel.processor.AbstractThrottler

AbstractThrottler.State

Field Summary

Fields inherited from class org.apache.camel.processor.AbstractThrottler

asyncDelayed, asyncExecutor, callerRunsWhenRejected, camelContext, DEFAULT_KEY, id, maxRequestsExpression, PROPERTY_EXCHANGE_QUEUED_TIMESTAMP, PROPERTY_EXCHANGE_STATE, rejectExecution, routeId, shutdownAsyncExecutor

Fields inherited from class org.apache.camel.support.service.BaseService

BUILT, FAILED, INITIALIZED, INITIALIZING, lock, NEW, SHUTDOWN, SHUTTING_DOWN, STARTED, STARTING, status, STOPPED, STOPPING, SUSPENDED, SUSPENDING

Constructor Summary

Constructors

Constructor	Description
TotalRequestsThrottler(org.apache.camel.CamelContext camelContext, org.apache.camel.Expression maxRequestsExpression, long timePeriodMillis, ScheduledExecutorService asyncExecutor, boolean shutdownAsyncExecutor, boolean rejectExecution, org.apache.camel.Expression correlation)

Method Summary

Modifier and Type	Method	Description
protected void	doShutdown()
protected void	doStart()
int	getCurrentMaximumRequests()	Gets the current maximum request per period value.
String	getMode()
long	getTimePeriodMillis()
String	getTraceLabel()
boolean	process(org.apache.camel.Exchange exchange, org.apache.camel.AsyncCallback callback)
protected boolean	processAsynchronously(org.apache.camel.Exchange exchange, org.apache.camel.AsyncCallback callback, org.apache.camel.processor.TotalRequestsThrottler.ThrottlingState throttlingState)	Delegate blocking on the DelayQueue to an asyncExecutor.
void	setTimePeriodMillis(long timePeriodMillis)	Sets the time period during which the maximum number of requests apply
String	toString()

Methods inherited from class org.apache.camel.processor.AbstractThrottler

getId, getMaximumRequestsExpression, getRouteId, handleException, handleInterrupt, isAsyncDelayed, isCallerRunsWhenRejected, isRejectExecution, setAsyncDelayed, setCallerRunsWhenRejected, setId, setMaximumRequestsExpression, setRejectExecution, setRouteId

Methods inherited from class org.apache.camel.support.AsyncProcessorSupport

process, processAsync

Methods inherited from class org.apache.camel.support.service.BaseService

build, doBuild, doFail, doInit, doLifecycleChange, doResume, doStop, doSuspend, fail, getStatus, init, isBuild, isInit, isNew, isRunAllowed, isShutdown, isStarted, isStarting, isStartingOrStarted, isStopped, isStopping, isStoppingOrStopped, isSuspended, isSuspending, isSuspendingOrSuspended, resume, shutdown, start, stop, suspend

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.camel.spi.IdAware

setGeneratedId

Methods inherited from interface org.apache.camel.Processor

process

Methods inherited from interface org.apache.camel.Service

build, close, init, start, stop

Methods inherited from interface org.apache.camel.ShutdownableService

shutdown

Methods inherited from interface org.apache.camel.StatefulService

getStatus, isRunAllowed, isStarted, isStarting, isStopped, isStopping, isSuspending

Methods inherited from interface org.apache.camel.SuspendableService

isSuspended, resume, suspend

Constructor Details

TotalRequestsThrottler

public TotalRequestsThrottler(org.apache.camel.CamelContext camelContext,
 org.apache.camel.Expression maxRequestsExpression,
 long timePeriodMillis,
 ScheduledExecutorService asyncExecutor,
 boolean shutdownAsyncExecutor,
 boolean rejectExecution,
 org.apache.camel.Expression correlation)

Method Details

process

public boolean process(org.apache.camel.Exchange exchange,
 org.apache.camel.AsyncCallback callback)

processAsynchronously

protected boolean processAsynchronously(org.apache.camel.Exchange exchange,
 org.apache.camel.AsyncCallback callback,
 org.apache.camel.processor.TotalRequestsThrottler.ThrottlingState throttlingState)

Delegate blocking on the DelayQueue to an asyncExecutor. Except if the executor rejects the submission and isCallerRunsWhenRejected() is enabled, then this method will delegate back to process(), but not before changing the exchange state to stop any recursion.

doStart

protected void doStart()
                throws Exception

Overrides:

doStart in class org.apache.camel.support.service.BaseService

Throws:

Exception

doShutdown

protected void doShutdown()
                   throws Exception

Overrides:

doShutdown in class org.apache.camel.support.service.BaseService

Throws:

Exception

getMode

public String getMode()

Specified by:

getMode in interface Throttler

Specified by:

getMode in class AbstractThrottler

getCurrentMaximumRequests

public int getCurrentMaximumRequests()

Gets the current maximum request per period value. If it is grouped throttling applied with correlationExpression than the max per period within the group will return

setTimePeriodMillis

public void setTimePeriodMillis(long timePeriodMillis)

Sets the time period during which the maximum number of requests apply

getTimePeriodMillis

public long getTimePeriodMillis()

getTraceLabel

public String getTraceLabel()

toString

public String toString()

Overrides:

toString in class Object