/*******************************************************************************
* Copyright (c) 2005 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.core.commands.operations;
/**
* <p>
* An undo context is used to "tag" operations as being applicable to a certain
* context. The undo context is used to filter the history of operations
* available for undo or redo so that only operations appropriate for a given
* undo context are shown when the application is presenting that context.
* </p>
* <p>
* The scope of an undo context is defined by the application that is making
* undo and redo of operations available. Undo contexts may be related to
* application models, or may be associated with UI objects that are providing
* undo and redo support.
* </p>
* <p>
* An undo context may be defined as "matching" another context. This allows
* applications to provide specialized implementations of an undo context that
* will appear in the operation history for their matching context.
*
* @since 3.1
*/
public interface IUndoContext {
/**
* Get the label that describes the undo context.
*
* @return the label for the context.
*/
public String getLabel();
/**
* Return whether the specified context is considered a match for the
* receiving context. When a context matches another context, operations
* that have the context are considered to also have the matching context.
*
* @param context
* the context to be checked against the receiving context.
*
* @return <code>true</code> if the receiving context can be considered a
* match for the specified context, and <code>false</code> if it
* cannot.
*/
public boolean matches(IUndoContext context);
}
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