org.freehep.util.commanddispatcher
Class CommandProcessor

java.lang.Object
  |
  +--java.util.Observable
        |
        +--org.freehep.util.commanddispatcher.CommandProcessor

Direct Known Subclasses:

Application.ApplicationCommandProcessor, MDITest.MDICommandProcessor, PageManager.PageManagerCommandProcessor, PluginManager.Commands, Test.MyCommandProcessor

public class CommandProcessor

extends Observable

A CommandProcessor represents a collection of CommandTargets. The CommandProcessor is Observable, and is normally Observed by the CommandTargetManager. When the CommandProcessor calls its notifyObservers method, the CommandTargetManager prompts each CommandSource currently attached to CommandTargets within the CommandProcessor to update their enabled/disabled status. Typically applications provide their own CommandProcessor(s) which extend this base class and which can handle a set of commands. By default CommandProcessor's acceptCommand method uses reflection to search for methods in the subClass which correspond to specific commands, although subclasses could also override the acceptCommand method to implement a different scheme. The default scheme looks for methods of type:

            public void onXXX()
 

to handle the command XXX. Also

            public void enableXXX(CommandState state)
 

to determine if the command is active or not.

Version:

$Id: CommandProcessor.java,v 1.8 2001/03/23 02:25:40 tonyj Exp $

Author:

Tony Johnson (tonyj@slac.stanford.edu)

Nested Class Summary

protected class	CommandProcessor.BooleanTarget Boolean target is an implementation of CommandTarget for command targets which can be swithced on/off.
protected class	CommandProcessor.SimpleTarget A SimpleTarget is an implementation of CommandTarget

Constructor Summary

CommandProcessor()

Method Summary

protected CommandTarget	acceptCommand(Class klass, String command) Uses reflection to check if the specified class has an "on" or "enable" method for this comamnd.
protected CommandTarget	acceptCommand(String command) The CommandTargetManager calls acceptCommand to find out if this CommandProcessor can respond to the specified command.
protected void	invoke(Method method, Object[] args)
protected void	invokeCommand(CommandProcessor.BooleanTarget t, boolean arg) Override this method to provide application specific handling for errors generated during command dispatch
protected void	invokeCommand(CommandProcessor.SimpleTarget t) Override this method to provide application specific handling for errors generated during command dispatch
protected void	invokeCommand(Method method, Object[] args)
protected void	invokeEnable(Method method, Object[] args)
void	setChanged()
protected void	setManager(CommandTargetManager m)
protected String	translate(String command) Translates a command.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers

Methods inherited from class java.lang.Object

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

Constructor Detail

CommandProcessor

public CommandProcessor()

Method Detail

translate

protected String translate(String command)

Translates a command. The default implementation removes trailing ..., and any spaces and then uppercases the first character .

setChanged

public void setChanged()

Overrides:

setChanged in class Observable

setManager

protected void setManager(CommandTargetManager m)

acceptCommand

protected CommandTarget acceptCommand(String command)

The CommandTargetManager calls acceptCommand to find out if this CommandProcessor can respond to the specified command. If it can it returns a CommandTarget for the command, otherwise it returns null.

Parameters:

command - The command to test for

acceptCommand

protected CommandTarget acceptCommand(Class klass,
                                      String command)

Uses reflection to check if the specified class has an "on" or "enable" method for this comamnd.

Parameters:

klass - The class to check

command - The command to test for

invoke

protected void invoke(Method method,
                      Object[] args)
               throws IllegalAccessException,
                      InvocationTargetException

IllegalAccessException

InvocationTargetException

invokeEnable

protected void invokeEnable(Method method,
                            Object[] args)
                     throws IllegalAccessException,
                            InvocationTargetException

IllegalAccessException

InvocationTargetException

invokeCommand

protected void invokeCommand(Method method,
                             Object[] args)
                      throws IllegalAccessException,
                             InvocationTargetException

IllegalAccessException

InvocationTargetException

invokeCommand

protected void invokeCommand(CommandProcessor.SimpleTarget t)

Override this method to provide application specific handling for errors generated during command dispatch

invokeCommand

protected void invokeCommand(CommandProcessor.BooleanTarget t,
                             boolean arg)

Override this method to provide application specific handling for errors generated during command dispatch