ptolemy.kernel.undo
Class UndoChangeRequest

java.lang.Object
  ptolemy.kernel.util.ChangeRequest
      ptolemy.kernel.undo.UndoChangeRequest

public class UndoChangeRequest
extends ChangeRequest

A change request to undo. When executed, this change request will identify the undo stack associated with the specified context, and it will execute the top undo action on that stack, if there is one.

Since:

Ptolemy II 3.1

Version:

$Id: UndoChangeRequest.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Edward A. Lee and Neil Smyth

Accepted Rating:

Green (hyzheng)

Proposed Rating:

Green (eal)

Field Summary

private NamedObj

_context

Constructor Summary

UndoChangeRequest(java.lang.Object originator, NamedObj context)
Construct a change request to be executed in the specified context.

Method Summary

protected void	_execute() Execute the change by invoking undo on the undo stack of the context specified in the constructor.
NamedObj	getContext() Return the context specified in the constructor, or null if none was specified.

Methods inherited from class ptolemy.kernel.util.ChangeRequest

addChangeListener, execute, getDescription, getLocality, getSource, isErrorReported, isPersistent, isStructuralChange, removeChangeListener, setDescription, setErrorReported, setListeners, setPersistent, waitForCompletion

Methods inherited from class java.lang.Object

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

Field Detail

_context

private NamedObj _context

Constructor Detail

UndoChangeRequest

public UndoChangeRequest(java.lang.Object originator,
                         NamedObj context)

Construct a change request to be executed in the specified context. The undo stack associated with the specified context will be used. That stack is the one returned by UndoStackAttribute.getUndoInfo().

Parameters:

originator - The originator of the change request.

context - The context in which to execute the MoML.

See Also:

UndoStackAttribute

Method Detail

getContext

public NamedObj getContext()

Return the context specified in the constructor, or null if none was specified.

Returns:

The context.

_execute

protected void _execute()
                 throws java.lang.Exception

Execute the change by invoking undo on the undo stack of the context specified in the constructor.

Specified by:

_execute in class ChangeRequest

Throws:

java.lang.Exception - If an exception is thrown while evaluating the request.