guarana.toolkit.task.routers
Class Resequencer

java.lang.Object
  extended by guarana.util.observer.smart.SmartObservable
      extended by guarana.framework.task.Task
          extended by guarana.toolkit.task.routers.Router
              extended by guarana.toolkit.task.routers.Resequencer
All Implemented Interfaces:
ISource, guarana.util.observer.smart.ISmartObserver

public class Resequencer
extends Router

Rebuild the correct sequence of split messages. When this sequence is completed this task publishes all messages in the sequence order to the output gateway. A resequencer does not change the state of inbound messages. It means the MESSAGE_ID is kept the same!

Graphical notation:


This is an Integration Pattern implementation

Problem: How can we get a stream of related but out-of-sequence messages back into the correct order?

Solution: Use a stateful filter, a Resequencer, to collect and re-order messages so that they can be published to the output channel in a specified order.

Since:
Guaranį SDK 1.0.0
Author:
Rafael Z. Frantz
See Also:
Resequencer pattern by Gregor Hohpe and Bobby Woolf for more details.

Details:

Field Summary
 
Fields inherited from class guarana.framework.task.Task
input, output
 
Constructor Summary
Resequencer(String name)
          Constructs a new resequencer task.
Resequencer(String name, int numberOfInputs, int numberOfOutputs)
          Constructs a new resequencer task.
 
Method Summary
 void execute()
          This method executes the business logic of this task.
 void update(guarana.util.observer.smart.SmartObservable slot, Object arg)
          This method is automatically called by the observable slot to notify the slot has received a message.
 
Methods inherited from class guarana.framework.task.Task
doWork, getName, getTriggerInterval, isTriggerTask, setName, setTriggerInterval
 
Methods inherited from class guarana.util.observer.smart.SmartObservable
addSmartObserver, containsSmartObserver, containsSmartObserver, countSmartObservers, deleteSmartObserver, deleteSmartObservers, hasChanged, notifySmartObservers, notifySmartObservers
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Resequencer

public Resequencer(String name)
Constructs a new resequencer task.

Parameters:
name - The name of the resequencer task.

Resequencer

public Resequencer(String name,
                   int numberOfInputs,
                   int numberOfOutputs)
Constructs a new resequencer task.

Parameters:
name - The name of this task.
numberOfInputs - The number of input gateways this task must have.
numberOfOutputs - The number of output gateways this task must have.
Method Detail

execute

public void execute()
             throws TaskExecutionException
This method executes the business logic of this task. It is automatically invoked by workers.

Overrides:
execute in class Task
Throws:
TaskExecutionException - to report any exception that has occurred during the execution of this method.
See Also:
TaskExecutionException

update

public void update(guarana.util.observer.smart.SmartObservable slot,
                   Object arg)
This method is automatically called by the observable slot to notify the slot has received a message. For all those tasks that can execute with one or more messages in its input slots, this method will add the task to the executable task reporter, so it can be executed. In this case the task execution will consume messages from all input slots.
Please, do not call this method by yourself. Overrides the implementation at Task for performance reasons.

Specified by:
update in interface guarana.util.observer.smart.ISmartObserver
Overrides:
update in class Task
Parameters:
slot - The Slot associated with this task.
arg - THIS PARAMETHER IS NOT USED.


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