/* 
 * This file is part of the Echo Web Application Framework (hereinafter "Echo").
 * Copyright (C) 2002-2009 NextApp, Inc.
 *
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 */

package nextapp.echo2.webcontainer.image;

import nextapp.echo2.app.Component;
import nextapp.echo2.app.ImageReference;

/**
 * An optional interface which may be implemented by 
 * <code>ComponentSynchronizePeer</code>s to render images via the
 * <code>ImageRenderService</code>.
 */
public interface ImageRenderSupport {

    /**
     * Retrieves the image identified by the given <code>imageId</code> value
     * for the given <code>Component</code>.
     * <p>
     * <strong>Note:</strong> A reference to any images to be rendered must be
     * maintained throughout the rendering process, due to the fact that the
     * image rendering subsystem creates a weak-keyed cache of images to be
     * rendered.  This method therefore may not simply return a new, 
     * otherwise-unreferenced image.  In the event that this presents a problem,
     * the recommended workaround is to simply store such otherwise unreferenced 
     * <code>ImageReference</code>s using a <code>RenderState</code> object.
     * 
     * @param component the component 
     * @param imageId the id of the image
     * @return the target image 
     */
    public ImageReference getImage(Component component, String imageId);
}