/*******************************************************************************
* Copyright (c) 2000, 2006 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.pde.internal.ui.editor;
import org.eclipse.jface.action.IAction;
import org.eclipse.pde.core.IModelChangeProvider;
/**
* Classes that implement this interface provide undo/redo
* capability linked to changes reported by model change
* providers. Model change events carry sufficient data
* to be used in an undo/redo stack and reverted to or
* reapplied after the change.
* <p>Model undo manager adds itself as a change listener
* after being connected to the provider. It is expected
* to stop listening to change events after being disconnected.
* Changes reported while being connected are kept in the
* operation stack whose size can be controlled.
* <p>The part that uses the undo manager is responsible
* for supplying Undo and Redo action objects for
* the purpose of controlling their availability.
* Undo manager should keep track of its current
* operation stack pointer and adjust Undo/Redo action
* availability by calling 'setEnabled' on the
* provided action objects. Implementation of this
* interface may also opt to modify Undo/Redo action
* labels in order to better indicate the effect
* of the operations if selected (for example,
* 'Undo Delete' instead of 'Undo').
*/
public interface IModelUndoManager {
/**
* Connects to the change provider. Until disconnecting,
* the manager will keep model changes in the operation
* stack and will be able to revert or reapply these
* changes in the source model.
* @param provider the model change provider to connect to
*/
public void connect(IModelChangeProvider provider);
/**
* Disconnects from the change provider. Upon disconnecting,
* the manager will no longer be able to revert or reapply
* changes in the source model.
* @param provider the model change provider to disconnect from
*/
public void disconnect(IModelChangeProvider provider);
/**
* Tests whether the current operation in the undo stack can
* be reverted.
* @return true if the current operation can be undone.
*/
public boolean isUndoable();
/**
* Tests whether the current operation in the undo stack can
* be reapplied.
* @return true if the current operation can be redone.
*/
public boolean isRedoable();
/**
* Reverts the current operation in the undo stack and decrements
* the stack pointer.
*/
public void undo();
/**
* Reapplies the next operation in the undo stack and sets
* the stack pointer to that operation.
*
*/
public void redo();
/**
* Sets the depth of the undo stack.
* @param limit number of levels in the undo stack.
*/
public void setUndoLevelLimit(int limit);
/**
* Temporarily suspends undo manager.
* @param ignore if true, model changes reported by the
* model change provider will be ignore until this
* property is set to <samp>false</samp> again.
*/
public void setIgnoreChanges(boolean ignore);
/**
* Connects the undo manager with the undo and redo actions
* in the workbench part using the manager. The manager
* uses these objects to enable or disable the actions
* according to the state of the undo stack and the current
* location of the stack pointer.
* @param undoAction the action in the workbench part that performs
* the undo operation.
* @param redoAction the action in the workbench part that performs
* the redo operation.
*/
public void setActions(IAction undoAction, IAction redoAction);
}
|