/*******************************************************************************
 * 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.core.commands.operations.UndoContext;

import dwtx.core.commands.operations.IUndoContext;

import dwt.dwthelper.utils;

/**
 * <p>
 * A simple, lightweight undo context that can be used to tag any operation. It
 * does not provided a specialized label. This class may be instantiated by
 * clients. This class may also be subclassed.
 * </p>
 *
 * @since 3.1
 */
public class UndoContext : IUndoContext {

    /**
     * <p>
     * Get the label that describes the undo context. The default implementation
     * returns the empty String. Subclasses may override.
     * </p>
     *
     * @return the label for the context.
     */
    public String getLabel() {
        return ""; //$NON-NLS-1$
    }

    /**
     * <p>
     * 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.
     * The default implementation checks whether the supplied context is
     * identical to this context. Subclasses may override.
     * </p>
     *
     * @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 bool matches(IUndoContext context) {
        return context is this;
    }
}