001 /*
002 * Copyright 1999-2001,2004 The Apache Software Foundation.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package org.apache.commons.workflow.web;
018
019
020 import java.io.IOException;
021 import java.util.EmptyStackException;
022 import javax.servlet.RequestDispatcher;
023 import javax.servlet.ServletException;
024 import javax.servlet.ServletRequest;
025 import javax.servlet.ServletResponse;
026 import org.apache.commons.workflow.Context;
027 import org.apache.commons.workflow.StepException;
028 import org.apache.commons.workflow.base.BaseStep;
029 import org.apache.commons.workflow.util.WorkflowUtils;
030
031
032 /**
033 * <p>Perform a <code>RequestDispatcher.include()</code> operation on the
034 * specified context relative path, and push the response data (as a String
035 * onto the evaluation stack.</p>
036 *
037 * <p>Supported Attributes:</p>
038 * <ul>
039 * <li><strong>page</strong> - Context relative URL (starting with a slash)
040 * of the application resource to be retrieved, or omitted to pop a
041 * computed String value from the top of the evaluation stack.</li>
042 * </ul>
043 *
044 * <p><strong>WARNING</strong> - This implementation requires a Servlet 2.3
045 * based container, because it uses the new response wrapper facilities.</p>
046 *
047 * <p><strong>DESIGN QUESTION - What about binary content?</strong></p>
048 *
049 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $
050 * @author Craig R. McClanahan
051 */
052
053 public class IncludeStep23 extends BaseStep {
054
055
056 // ----------------------------------------------------------= Constructors
057
058
059 /**
060 * Construct a default instance of this Step.
061 */
062 public IncludeStep23() {
063
064 super();
065
066 }
067
068
069 /**
070 * Construct an instance of this Step with the specified identifier.
071 *
072 * @param id Step identifier
073 */
074 public IncludeStep23(String id) {
075
076 super();
077 setId(id);
078
079 }
080
081
082 /**
083 * Construct a fully configured instance of this Step.
084 *
085 * @param id Step identifier
086 * @param page Context-relative url
087 */
088 public IncludeStep23(String id, String page) {
089
090 super();
091 setId(id);
092 setPage(page);
093
094 }
095
096
097 // ------------------------------------------------------------- Properties
098
099
100 /**
101 * The context-relative URL (starting with '/') of the resource to be
102 * retrieved.
103 */
104 protected String page = null;
105
106 public String getPage() {
107 return (this.page);
108 }
109
110 public void setPage(String page) {
111 this.page = page;
112 }
113
114
115 // --------------------------------------------------------- Public Methods
116
117
118 /**
119 * Perform the executable actions related to this Step, in the context of
120 * the specified Context.
121 *
122 * @param context The Context that is tracking our execution state
123 *
124 * @exception StepException if a processing error has occurred
125 */
126 public void execute(Context context) throws StepException {
127
128 // Make sure our executing Context is a WebContext
129 if (!(context instanceof WebContext))
130 throw new StepException("Execution context is not a WebContext",
131 this);
132 WebContext webContext = (WebContext) context;
133
134 // Get the actual resource reference we will be using
135 String resource = page;
136 if (resource == null) {
137 try {
138 resource = (String) webContext.pop();
139 } catch (EmptyStackException e) {
140 throw new StepException("Evaluation stack is empty", this);
141 }
142 }
143
144 // Create a request dispatcher and response wrapper for this resource
145 RequestDispatcher rd =
146 webContext.getServletContext().getRequestDispatcher(resource);
147 if (rd == null)
148 throw new StepException("No request dispatcher for '" +
149 resource + "'", this);
150 ServletRequest request = webContext.getServletRequest();
151 ServletResponse response =
152 new IncludeResponse23(webContext.getServletResponse());
153
154 // Request the included resource
155 String content = null;
156 try {
157 rd.include(request, response);
158 content = ((IncludeResponse23) response).getContent();
159 } catch (IOException e) {
160 throw new StepException("IOException including '" +
161 resource + "'", e, this);
162 } catch (ServletException e) {
163 throw new StepException("ServletException including '" +
164 resource + "'", e, this);
165 }
166
167 // Push the resulting String onto the evaluation stack
168 webContext.push(content);
169
170 }
171
172
173 /**
174 * Render a string representation of this Step.
175 */
176 public String toString() {
177
178 StringBuffer sb = new StringBuffer("<web:include");
179 if (getId() != null) {
180 sb.append(" id=\"");
181 sb.append(getId());
182 sb.append("\"");
183 }
184 sb.append(" page=\"");
185 sb.append(getPage());
186 sb.append("\"/>");
187 return (sb.toString());
188
189 }
190
191
192 }