org.apache.excalibur.event.command
Class CommandManager

java.lang.Object
  org.apache.avalon.framework.logger.AbstractLogEnabled
      org.apache.excalibur.event.command.CommandManager

All Implemented Interfaces:

Disposable, EnqueuePredicate, EventPipeline, LogEnabled

public class CommandManager

extends AbstractLogEnabled

implements EventPipeline, Disposable, EnqueuePredicate

The CommandManager handles asynchronous commands from the rest of the system. The only exposed piece is the Queue that other components use to give Commands to this system. You must register this with a ThreadManager for it to work.

Source Example

 //
 // Set up the ThreadManager that the CommandManager will use
 //

 ThreadManager threadManager = new TPCThreadManager();
 threadManager.enableLogging( getLogger().getChildLogger("threadmanager") );
 Parameters params = new Parameters();
 params.setParameter( "threads-per-processor", "2" );
 params.setParameter( "sleep-time", "1000" );
 params.setParameter( "block-timeout", "250" );
 threadManager.parameterize( params );
 threadManager.initialize();

 //
 // Set up the CommandManager
 //

 CommandManager commandManager = new CommandManager();
 commandManager.enableLogging( getLogger().getChildLogger("commandmanager") );
 threadManager.register( commandManager );
 

Author:

Avalon Development Team

Constructor Summary

CommandManager()
Create the CommandManager

Method Summary

boolean	accept(java.lang.Object[] elements, Sink modifyingSink) Tests the given element for acceptance onto the m_sink.
boolean	accept(java.lang.Object element, Sink modifyingSink) Tests the given element for acceptance onto the m_sink.
void	deregisterSignalHandler(Signal signal, EventHandler handler) Deregister a Signal with an EventHandler.
void	dispose() When you are done with CommandManager, call this and it will clean up all its resources.
protected CommandFailureHandler	getCommandFailureHandler() Get the failure handler so that CommandManager can use it when a problem happens.
Sink	getCommandSink() Get the Command Sink so that you can enqueue new commands.
EventHandler	getEventHandler() Used by the ThreadManager to get the EventHandler for the CommandManager.
Source[]	getSources() Used by the Threadmanager to get the sources that are feeding the CommandManager.
void	registerSignalHandler(Signal signal, EventHandler handler) Register a Signal with an EventHandler.
void	setCommandFailureHandler(CommandFailureHandler handler) Set the failure handler that the application can use to override what happens when a command failure happens.

Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled

enableLogging, getLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

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

Constructor Detail

CommandManager

public CommandManager()

Create the CommandManager

Method Detail

setCommandFailureHandler

public void setCommandFailureHandler(CommandFailureHandler handler)

Set the failure handler that the application can use to override what happens when a command failure happens.

Parameters:

handler - the new Handler

Throws:

java.lang.NullPointerException - if "handler" is null.

getCommandFailureHandler

protected CommandFailureHandler getCommandFailureHandler()

Get the failure handler so that CommandManager can use it when a problem happens.

Returns:

the failure handler.

getCommandSink

public final Sink getCommandSink()

Get the Command Sink so that you can enqueue new commands.

Returns:

the Sink that feeds the CommandManager

registerSignalHandler

public final void registerSignalHandler(Signal signal,
                                        EventHandler handler)

Register a Signal with an EventHandler. The Signal is a special object that implements the Signal interface. When CommandManager recieves events that match the Signal, it will send a copy of it to all the EventHandlers attached to it.

Parameters:

signal - The signal we are listening for.

handler - The handler that wants to be notified

deregisterSignalHandler

public final void deregisterSignalHandler(Signal signal,
                                          EventHandler handler)

Deregister a Signal with an EventHandler. Stop notifying the particular EventHandler that is passed in about the associated Signal.

Parameters:

signal - The signal we are listening for.

handler - The handler that wants to be notified

dispose

public void dispose()

When you are done with CommandManager, call this and it will clean up all its resources.

Specified by:

dispose in interface Disposable

getSources

public final Source[] getSources()

Used by the Threadmanager to get the sources that are feeding the CommandManager.

Specified by:

getSources in interface EventPipeline

Returns:

the Array of one Source

getEventHandler

public final EventHandler getEventHandler()

Used by the ThreadManager to get the EventHandler for the CommandManager.

Specified by:

getEventHandler in interface EventPipeline

Returns:

the EventHandler

accept

public boolean accept(java.lang.Object element,
                      Sink modifyingSink)

Tests the given element for acceptance onto the m_sink.

Specified by:

accept in interface EnqueuePredicate

Parameters:

element - The element to enqueue

modifyingSink - The sink that is used for this predicate

Returns:

true if the sink accepts the element; false otherwise.

Since:

Feb 10, 2003

accept

public boolean accept(java.lang.Object[] elements,
                      Sink modifyingSink)

Tests the given element for acceptance onto the m_sink.

Specified by:

accept in interface EnqueuePredicate

Parameters:

elements - The array of elements to enqueue

modifyingSink - The sink that is used for this predicate

Returns:

true if the sink accepts all the elements; false otherwise.

Since:

Feb 10, 2003