001    /**
002     * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.struts;
016    
017    import com.liferay.portal.kernel.servlet.HttpHeaders;
018    import com.liferay.portal.kernel.util.ContentTypes;
019    import com.liferay.portal.util.PortalUtil;
020    
021    import java.io.PrintWriter;
022    
023    import javax.servlet.http.HttpServletRequest;
024    import javax.servlet.http.HttpServletResponse;
025    
026    import org.apache.struts.action.Action;
027    import org.apache.struts.action.ActionForm;
028    import org.apache.struts.action.ActionForward;
029    import org.apache.struts.action.ActionMapping;
030    
031    /**
032     * @author Brian Wing Shun Chan
033     */
034    public abstract class AJAXAction extends Action {
035    
036            public ActionForward execute(
037                            ActionMapping mapping, ActionForm form, HttpServletRequest request,
038                            HttpServletResponse response)
039                    throws Exception {
040    
041                    String text = null;
042    
043                    try {
044                            text = getText(mapping, form, request, response);
045                    }
046                    catch (Exception e) {
047                            PortalUtil.sendError(
048                                    HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e, request,
049                                    response);
050    
051                            return null;
052                    }
053    
054                    response.setContentType(ContentTypes.TEXT_PLAIN_UTF8);
055                    response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache");
056    
057                    PrintWriter pw = response.getWriter();
058    
059                    pw.write(text);
060    
061                    pw.close();
062    
063                    return null;
064            }
065    
066            public abstract String getText(
067                            ActionMapping mapping, ActionForm form, HttpServletRequest request,
068                            HttpServletResponse response)
069                    throws Exception;
070    
071    }