guarana.toolkit.task.routers
Class Filter
java.lang.Object
guarana.util.observer.smart.SmartObservable
guarana.framework.task.Task
guarana.toolkit.task.routers.Router
guarana.toolkit.task.routers.Filter
- All Implemented Interfaces:
- ISource, guarana.util.observer.smart.ISmartObserver
public abstract class Filter
- extends Router
Removes from the message flow unwanted messages. The filter task may or may not publish an outbound message
to the output slot. If log INFO level is activated, a filtered messages causes its MESSAGE_ID to be written to the log.
A filter 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 a component avoid receiving uninteresting messages?
Solution: Use a special kind of Message Router, a Message Filter, to eliminate undesired messages from a channel based on a set of criteria.
- Since:
- Guaranį SDK 1.0.0
- Author:
- Rafael Z. Frantz
- See Also:
- Message Filter pattern by Gregor Hohpe and Bobby Woolf for more details.
Details:
- Number of Inputs: 1
- Number of Outputs: 1
Constructor Summary |
Filter(String name)
Constructs a new filter task. |
Filter(String name,
int numberOfInputs,
int numberOfOutputs)
Constructs a new filter task. |
Method Summary |
abstract void |
doWork(Exchange exchange)
This method implements 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.util.observer.smart.SmartObservable |
addSmartObserver, containsSmartObserver, containsSmartObserver, countSmartObservers, deleteSmartObserver, deleteSmartObservers, hasChanged, notifySmartObservers, notifySmartObservers |
Filter
public Filter(String name)
- Constructs a new filter task.
- Parameters:
name
- The name of the filter task.
Filter
public Filter(String name,
int numberOfInputs,
int numberOfOutputs)
- Constructs a new filter 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.
doWork
public abstract void doWork(Exchange exchange)
throws TaskExecutionException
- This method implements the business logic of this task.
Filters an inbound message. The filtering policy must be provided by the end user as the implementation of this method.
- Overrides:
doWork
in class Task
- Parameters:
exchange
- An exchange object that holds the inbound messages of this task.
- Throws:
TaskExecutionException
- to report any exception that has occurred during the execution of this method.
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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