com.iizigo.editor

Class UndoTransaction

java.lang.Object

org.eclipse.core.commands.operations.AbstractOperation

com.iizigo.editor.UndoTransaction

All Implemented Interfaces:

IUndoableOperation

public class UndoTransaction
extends AbstractOperation

Class used to create transactions in the operations history. Construct a new UndoTransaction instance to start the transaction, and call commit at the end, as simple as that! If it fails, call rollback, but ALWAYS make sure either commit or rollback is called using try-catch-finally, otherwise there may be leaks due to history listeners.

Author:

Christopher Mindus

Constructor Summary

Constructors

Constructor and Description
UndoTransaction(String description, IUndoContext undoContext) Constructor used to begin the undo transaction.

Method Summary

Modifier and Type	Method and Description
boolean	canExecute()
boolean	canRedo()
boolean	canUndo()
void	commit() Commits a series of operations in a transaction initiated with a prior call to begin.
void	dispose()
IStatus	execute(IProgressMonitor monitor, IAdaptable info)
IStatus	redo(IProgressMonitor monitor, IAdaptable info)
boolean	rollback(Shell shell, boolean performUndo) Performs a rollback.
IStatus	undo(IProgressMonitor monitor, IAdaptable info)

Methods inherited from class org.eclipse.core.commands.operations.AbstractOperation

addContext, getContexts, getLabel, hasContext, removeContext, setLabel, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

UndoTransaction

public UndoTransaction(String description,
                       IUndoContext undoContext)

Constructor used to begin the undo transaction.

It is very important to call commit or rollback in all cases, use try-catch-finally to ensure this is done even when exceptions occur.

Parameters:

description - The description of the entire operation.

Method Detail

rollback

public boolean rollback(Shell shell,
                        boolean performUndo)

Performs a rollback.

Parameters:

shell - The shell, can be set to null if performUndo is false.

performUndo - Flag indicating that operations already performed should be undone as much as possible. The operations that have been undone are removed from history, the ones not successful are left without change and no "global" transaction undo operation is used.

Returns:

Success flag when performUndo is true. false indicates at least one operation failed to be undone, true indicates all operations are undone.

commit

public void commit()

Commits a series of operations in a transaction initiated with a prior call to begin.

dispose

public void dispose()

Specified by:

dispose in interface IUndoableOperation

Overrides:

dispose in class AbstractOperation

canExecute

public boolean canExecute()

Specified by:

canExecute in interface IUndoableOperation

Overrides:

canExecute in class AbstractOperation

canRedo

public boolean canRedo()

Specified by:

canRedo in interface IUndoableOperation

Overrides:

canRedo in class AbstractOperation

canUndo

public boolean canUndo()

Specified by:

canUndo in interface IUndoableOperation

Overrides:

canUndo in class AbstractOperation

execute

public IStatus execute(IProgressMonitor monitor,
                       IAdaptable info)
                throws ExecutionException

Specified by:

execute in interface IUndoableOperation

Specified by:

execute in class AbstractOperation

Throws:

ExecutionException

redo

public IStatus redo(IProgressMonitor monitor,
                    IAdaptable info)
             throws ExecutionException

Specified by:

redo in interface IUndoableOperation

Specified by:

redo in class AbstractOperation

Throws:

ExecutionException

undo

public IStatus undo(IProgressMonitor monitor,
                    IAdaptable info)
             throws ExecutionException

Specified by:

undo in interface IUndoableOperation

Specified by:

undo in class AbstractOperation

Throws:

ExecutionException