org.eclipse.emf.edit.command
Class ChangeCommand

java.lang.Object
  org.eclipse.emf.common.command.AbstractCommand
      org.eclipse.emf.edit.command.ChangeCommand

All Implemented Interfaces:

Command

public abstract class ChangeCommand
extends AbstractCommand

This command uses the Change Model facilities to enable a group of modifications to be executed as one single command. The undo operation reverts all the modifications made when the command was executed

In order to use this class, the org.eclipse.emf.ecore.change plugin has to be available in your Eclipse configuration.

Since:

2.2.0

Nested Class Summary

Nested classes/interfaces inherited from class org.eclipse.emf.common.command.AbstractCommand

AbstractCommand.NonDirtying

Field Summary

protected ChangeDescription	changeDescription
protected ChangeRecorder	changeRecorder
protected Notifier	notifier
protected java.util.Collection<Notifier>	notifiers

Fields inherited from class org.eclipse.emf.common.command.AbstractCommand

description, isExecutable, isPrepared, label

Constructor Summary

protected	ChangeCommand(ChangeRecorder changeRecorder)
	ChangeCommand(ChangeRecorder changeRecorder, java.util.Collection<Notifier> notifiers)
	ChangeCommand(ChangeRecorder changeRecorder, Notifier notifier)
	ChangeCommand(java.util.Collection<Notifier> notifiers)
	ChangeCommand(Notifier notifier)

Method Summary

boolean	canUndo() Returns true because most command should be undoable.
protected ChangeRecorder	createChangeRecorder()
void	dispose() Called to indicate that the command will never be used again.
protected void	disposeChangeRecorder(ChangeRecorder changeRecorder) Disposes the ChangeRecorder created by execute().
protected abstract void	doExecute() Subclasses should override this to perform modifications to resources and objects.
void	execute() Executes the command.
protected ChangeDescription	getChangeDescription()
ChangeRecorder	getChangeRecorder() Returns the ChangeRecorder specified in the constructor if any.
protected boolean	prepare() Called at most once in AbstractCommand.canExecute() to give the command an opportunity to ready itself for execution.
void	redo() Performs the command activity required to redo the effect after undoing the effect.
protected void	setChangeDescription(ChangeDescription changeDescription)
void	undo() Throws a runtime exception.

Methods inherited from class org.eclipse.emf.common.command.AbstractCommand

canExecute, chain, getAffectedObjects, getDescription, getLabel, getResult, setDescription, setLabel, toString

Methods inherited from class java.lang.Object

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

Field Detail

changeDescription

protected ChangeDescription changeDescription

notifier

protected Notifier notifier

notifiers

protected java.util.Collection<Notifier> notifiers

changeRecorder

protected ChangeRecorder changeRecorder

Constructor Detail

ChangeCommand

protected ChangeCommand(ChangeRecorder changeRecorder)

ChangeCommand

public ChangeCommand(ChangeRecorder changeRecorder,
                     Notifier notifier)

ChangeCommand

public ChangeCommand(Notifier notifier)

ChangeCommand

public ChangeCommand(ChangeRecorder changeRecorder,
                     java.util.Collection<Notifier> notifiers)

ChangeCommand

public ChangeCommand(java.util.Collection<Notifier> notifiers)

Method Detail

dispose

public void dispose()

Description copied from interface: Command

Called to indicate that the command will never be used again. Calling any other method after this one has undefined results.

Specified by:

dispose in interface Command

Overrides:

dispose in class AbstractCommand

getChangeRecorder

public ChangeRecorder getChangeRecorder()

Returns the ChangeRecorder specified in the constructor if any.

Returns:

ChangeRecorder

createChangeRecorder

protected ChangeRecorder createChangeRecorder()

getChangeDescription

protected ChangeDescription getChangeDescription()

setChangeDescription

protected void setChangeDescription(ChangeDescription changeDescription)

prepare

protected boolean prepare()

Description copied from class: AbstractCommand

Called at most once in AbstractCommand.canExecute() to give the command an opportunity to ready itself for execution. The returned value is stored in AbstractCommand.canExecute(). In other words, you can override this method to initialize and to yield a cached value for the all subsequent calls to canExecute.

Overrides:

prepare in class AbstractCommand

Returns:

whether the command is executable.

canUndo

public boolean canUndo()

Description copied from class: AbstractCommand

Returns true because most command should be undoable.

Specified by:

canUndo in interface Command

Overrides:

canUndo in class AbstractCommand

Returns:

true.

execute

public void execute()

Executes the command. Subclasses are not expected to overwrite this method, and implement their changes on doExecute().

doExecute

protected abstract void doExecute()

Subclasses should override this to perform modifications to resources and objects. If no modification occurs, an AbortExecutionException may be thrown to avoid placing the command on the command stack.

disposeChangeRecorder

protected void disposeChangeRecorder(ChangeRecorder changeRecorder)

Disposes the ChangeRecorder created by execute(). The default implementation doesn't dispose the change recorder if it was passed in through one of the constructor methods.

Parameters:

changeRecorder -

undo

public void undo()

Description copied from class: AbstractCommand

Throws a runtime exception.

Specified by:

undo in interface Command

Overrides:

undo in class AbstractCommand

redo

public void redo()

Description copied from interface: Command

Performs the command activity required to redo the effect after undoing the effect. The effect, if any, of calling redo before undo is called is undefined. Note that if you implement redo to call execute then any derived class will be restricted by that decision also.