http://www.eclipse.org/platform: Commands (Eclipse Foundation) 
Copyright (c) 2005, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation

/*******************************************************************************
 * Copyright (c) 2005, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.commands.operations;



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.




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.




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
/**
 * <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.

Returns:the label for the context.
/**
	 * 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.

Params:
  • context – 
           the context to be checked against the receiving context.
Returns:true if the receiving context can be considered a
        match for the specified context, and false if it
        cannot.
/**
	 * 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);

}