Package org.apache.camel.processor

Class Throttler

java.lang.Object
org.apache.camel.support.service.BaseService
org.apache.camel.support.service.ServiceSupport
org.apache.camel.support.AsyncProcessorSupport
org.apache.camel.processor.Throttler
All Implemented Interfaces:
AutoCloseable, org.apache.camel.AsyncProcessor, org.apache.camel.Processor, 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 Throttler extends org.apache.camel.support.AsyncProcessorSupport implements org.apache.camel.Traceable, org.apache.camel.spi.IdAware, org.apache.camel.spi.RouteIdAware
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.

  • Field Summary

    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
    Throttler(org.apache.camel.CamelContext camelContext, org.apache.camel.Expression maxRequestsPerPeriodExpression, 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()
     
    protected void
    doStop()
     
    int
    getCurrentMaximumRequestsPerPeriod()
    Gets the current maximum request per period value.
    String
    getId()
     
    org.apache.camel.Expression
    getMaximumRequestsPerPeriodExpression()
     
    String
    getRouteId()
     
    long
    getTimePeriodMillis()
     
    String
    getTraceLabel()
     
    boolean
    isAsyncDelayed()
     
    boolean
    isCallerRunsWhenRejected()
     
    boolean
    isRejectExecution()
     
    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.Throttler.ThrottlingState throttlingState)
    Delegate blocking on the DelayQueue to an asyncExecutor.
    void
    setAsyncDelayed(boolean asyncDelayed)
     
    void
    setCallerRunsWhenRejected(boolean callerRunsWhenRejected)
     
    void
    setId(String id)
     
    void
    setMaximumRequestsPerPeriodExpression(org.apache.camel.Expression maxRequestsPerPeriodExpression)
    Sets the maximum number of requests per time period expression
    void
    setRejectExecution(boolean rejectExecution)
     
    void
    setRouteId(String routeId)
     
    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.support.AsyncProcessorSupport

    process, processAsync

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

    build, doBuild, doFail, doInit, doLifecycleChange, doResume, 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.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

    • Throttler

      public Throttler(org.apache.camel.CamelContext camelContext, org.apache.camel.Expression maxRequestsPerPeriodExpression, 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)
      Specified by:
      process in interface org.apache.camel.AsyncProcessor

    • processAsynchronously

      protected boolean processAsynchronously(org.apache.camel.Exchange exchange, org.apache.camel.AsyncCallback callback, org.apache.camel.processor.Throttler.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

    • doStop

      protected void doStop() throws Exception
      Overrides:
      doStop 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

    • isRejectExecution

      public boolean isRejectExecution()

    • setRejectExecution

      public void setRejectExecution(boolean rejectExecution)

    • isAsyncDelayed

      public boolean isAsyncDelayed()

    • setAsyncDelayed

      public void setAsyncDelayed(boolean asyncDelayed)

    • isCallerRunsWhenRejected

      public boolean isCallerRunsWhenRejected()

    • setCallerRunsWhenRejected

      public void setCallerRunsWhenRejected(boolean callerRunsWhenRejected)

    • getId

      public String getId()
      Specified by:
      getId in interface org.apache.camel.spi.HasId

    • setId

      public void setId(String id)
      Specified by:
      setId in interface org.apache.camel.spi.IdAware

    • getRouteId

      public String getRouteId()
      Specified by:
      getRouteId in interface org.apache.camel.spi.RouteIdAware

    • setRouteId

      public void setRouteId(String routeId)
      Specified by:
      setRouteId in interface org.apache.camel.spi.RouteIdAware

    • setMaximumRequestsPerPeriodExpression

      public void setMaximumRequestsPerPeriodExpression(org.apache.camel.Expression maxRequestsPerPeriodExpression)
      Sets the maximum number of requests per time period expression

    • getMaximumRequestsPerPeriodExpression

      public org.apache.camel.Expression getMaximumRequestsPerPeriodExpression()

    • getCurrentMaximumRequestsPerPeriod

      public int getCurrentMaximumRequestsPerPeriod()
      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()
      Specified by:
      getTraceLabel in interface org.apache.camel.Traceable

    • toString

      public String toString()
      Overrides:
      toString in class Object