1 /*
2 * $Id: DefinitionDispatcherAction.java 471754 2006-11-06 14:55:09Z husted $
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 package org.apache.struts.tiles.actions;
23
24 import java.io.IOException;
25 import java.io.PrintWriter;
26
27 import javax.servlet.http.HttpServletRequest;
28 import javax.servlet.http.HttpServletResponse;
29
30 import org.apache.commons.logging.Log;
31 import org.apache.commons.logging.LogFactory;
32 import org.apache.struts.action.Action;
33 import org.apache.struts.action.ActionForm;
34 import org.apache.struts.action.ActionForward;
35 import org.apache.struts.action.ActionMapping;
36 import org.apache.struts.tiles.ComponentDefinition;
37 import org.apache.struts.tiles.DefinitionsFactoryException;
38 import org.apache.struts.tiles.DefinitionsUtil;
39 import org.apache.struts.tiles.FactoryNotFoundException;
40 import org.apache.struts.tiles.NoSuchDefinitionException;
41 import org.apache.struts.tiles.TilesUtil;
42
43 /**
44 * <p>An <strong>Action</strong> that dispatches to a Tiles Definition
45 * that is named by the request parameter whose name is specified
46 * by the <code>parameter</code> property of the corresponding
47 * ActionMapping.
48 * This action is useful in following situations:
49 * <li>
50 * <ul>To associate an Url to a definition</ul>
51 * <ul>To use Struts <html:link> tag on a definition</ul>
52 * </li>
53 * <p>To configure the use of this action in your
54 * <code>struts-config.xml</code> file, create an entry like this:</p>
55 *
56 * <code>
57 * <action path="/saveSubscription"
58 * type="org.apache.struts.tiles.actions.DefinitionDispatcherAction"
59 * parameter="def"/>
60 * <forward name="success" path="anything" //>
61 * <forward name="error" path="path.to.error.page" //>
62 * </code>
63 *
64 * <p>which will use the value of the request parameter named "def"
65 * to pick the appropriate definition name.
66 * <p> The value for success doesn't matter. The forward will forward to
67 * appropriate definition.
68 * <p> The value for error should denote a valid jsp path or definition name.
69 *
70 * @version $Rev: 471754 $ $Date: 2006-11-06 08:55:09 -0600 (Mon, 06 Nov 2006) $
71 */
72 public class DefinitionDispatcherAction extends Action {
73
74 /**
75 * Commons Logging instance.
76 */
77 protected static Log log = LogFactory.getLog(DefinitionDispatcherAction.class);
78
79 /**
80 * Process the specified HTTP request, and create the corresponding HTTP
81 * response (or forward to another web component that will create it),
82 * with provision for handling exceptions thrown by the business logic.
83 *
84 * @param mapping The ActionMapping used to select this instance
85 * @param form The optional ActionForm bean for this request (if any)
86 * @param request The HTTP request we are processing
87 * @param response The HTTP response we are creating
88 *
89 * @exception Exception if the application business logic throws
90 * an exception
91 * @since Struts 1.1
92 */
93 public ActionForward execute(
94 ActionMapping mapping,
95 ActionForm form,
96 HttpServletRequest request,
97 HttpServletResponse response)
98 throws Exception {
99
100 // Identify the request parameter containing the method name
101 // If none defined, use "def"
102 String parameter = mapping.getParameter();
103 if (parameter == null) {
104 parameter = "def";
105 }
106
107 // Identify the method name to be dispatched to
108 String name = request.getParameter(parameter);
109 if (name == null) {
110 log.error("Can't get parameter '" + parameter + "'.");
111
112 return mapping.findForward("error");
113 }
114
115 // Try to dispatch to requested definition
116 try {
117 // Read definition from factory, but we can create it here.
118 ComponentDefinition definition =
119 TilesUtil.getDefinition(
120 name,
121 request,
122 getServlet().getServletContext());
123
124 if (log.isDebugEnabled()) {
125 log.debug("Get Definition " + definition);
126 }
127
128 DefinitionsUtil.setActionDefinition(request, definition);
129
130 } catch (FactoryNotFoundException e) {
131 log.error("Can't get definition factory.", e);
132 return mapping.findForward("error");
133
134 } catch (NoSuchDefinitionException e) {
135 log.error("Can't get definition '" + name + "'.", e);
136 return mapping.findForward("error");
137
138 } catch (DefinitionsFactoryException e) {
139 log.error("General Factory error '" + e.getMessage() + "'.", e);
140 return mapping.findForward("error");
141
142 } catch (Exception e) {
143 log.error("General error '" + e.getMessage() + "'.", e);
144 return mapping.findForward("error");
145 }
146
147 return mapping.findForward("success");
148
149 }
150
151 /**
152 * @deprecated This will be removed after Struts 1.2.
153 */
154 protected void printError(HttpServletResponse response, String msg)
155 throws IOException {
156 response.setContentType("text/plain");
157 PrintWriter writer = response.getWriter();
158 writer.println(msg);
159 writer.flush();
160 writer.close();
161 }
162 }