001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.gwt.client.util;
029
030import com.google.gwt.core.client.JavaScriptObject;
031
032/**
033 * Helper class used to create a native Javascript function to call into GWT code.<p>
034 */
035public class CmsScriptCallbackHelper {
036
037    /** The stored arguments. */
038    protected JavaScriptObject m_arguments;
039
040    /**
041     * Creates a native JS function which, when executed, calls this object's run() method.<p>
042     *
043     * @return the JS function
044     */
045    public native JavaScriptObject createCallback() /*-{
046        var self = this;
047        return function() {
048            self.@org.opencms.gwt.client.util.CmsScriptCallbackHelper::setArguments(Lcom/google/gwt/core/client/JavaScriptObject;)(arguments);
049            self.@org.opencms.gwt.client.util.CmsScriptCallbackHelper::run()();
050        }
051    }-*/;
052
053    /**
054     * Installs the Javascript function  generated by this helper as a global function, i.e. an attribute on 'window'.<p>
055     *
056     * @param name the function name
057     */
058    public void installCallbackOnWindow(String name) {
059
060        CmsJsUtil.setAttribute(CmsJsUtil.getWindow(), name, createCallback());
061    }
062
063    /**
064     * This method is called by the callback created by createCallback().<p>
065     */
066    public void run() {
067        // override this method to put actual logic here
068    }
069
070    /**
071     * Sets the function arguments so they can be accessed later in the run() method.<p>
072     *
073     * @param arguments the function arguments
074     */
075    public void setArguments(JavaScriptObject arguments) {
076
077        m_arguments = arguments;
078    }
079
080}