/*******************************************************************************
 * Copyright (c) 2000, 2007 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.ui;

/**
 * Manages a list of entries to keep a history of locations on editors,
 * enabling the user to go back and forward without losing context.
 * 
 * The history is a list of <code>INavigationLocation</code> and a pointer
 * to the current location. Whenever the back or forward action runs the
 * history restores the previous or next location.
 *
 * The back and/or forward actions should not change the content of the history
 * in any way.
 * 
 * If the user steps N times in one direction (back or forward) and then N times to
 * the oposite direction, the editor and location should be exactly the same as before.
 * 
 * Clients must guarantee that the current location is
 * always in the history, which can be done either by marking
 * a new location or by updating the current location.
 * 
 * Not intended to be implemented by clients.
 * 
 * @since 2.1
 */
public interface INavigationHistory {
    /**
     * Mark the current location into the history. This message
     * should be sent by clients whenever significant changes
     * in location are detected.
     * 
     * The location is obtained by calling <code>INavigationLocationProvider.createNavigationLocation</code>
     * 
     * @param part the editor part
     */
    public void markLocation(IEditorPart part);

    /**
     * Returns the current location.
     * 
     * @return the current location
     */
    public INavigationLocation getCurrentLocation();

    /**
     * Returns all entries in the history.
     * 
     * @return all entries in the history
     */
    public INavigationLocation[] getLocations();
}