/*******************************************************************************
 * Copyright (c) 2004 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.presentations;

/**
 * This interface is given to a StackPresentation when it is loading or saving
 * its state.
 * 
 * Not intended to be implemented by clients
 * 
 * @since 3.0
 */
public interface IPresentationSerializer {
    /**
     * Returns a unique identifier for the given part. The identifier can later
     * be used to restore the original part by calling getPart(...). This identifier 
     * is guaranteed to be unique within a particular StackPresentation. However, 
     * the same part may be assigned a different ID each time the presentation is saved. 
     * 
     * @param part a part to be identified (not null)
     * @return a unique identifier for the part (not null)
     */
    public String getId(IPresentablePart part);

    /**
     * Returns a presentable part, given an id that was generated when the presentation 
     * was saved.
     * 
     * @param id an ID that was generated by getId(IPresentablePart) when the presentation
     * was saved
     * @return the presentable part associated with the given id, or null if none. Note
     * that even if the ID was valid when the presentation was saved, it may not
     * be valid when the presentation is restored. Callers must be prepared
     * to handle a null result.
     */
    public IPresentablePart getPart(String id);
}