IncludeTag


1   /*
2    * $Id: IncludeTag.java 54929 2004-10-16 16:38:42Z germuska $ 
3    *
4    * Copyright 1999-2004 The Apache Software Foundation.
5    * 
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * You may obtain a copy of the License at
9    * 
10   *      http://www.apache.org/licenses/LICENSE-2.0
11   * 
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.struts.taglib.bean;
20  
21  import java.io.BufferedInputStream  ;
22  import java.io.InputStreamReader  ;
23  import java.net.HttpURLConnection  ;
24  import java.net.MalformedURLException  ;
25  import java.net.URL  ;
26  import java.net.URLConnection  ;
27  import java.util.Map  ;
28  import javax.servlet.http.HttpServletRequest  ;
29  import javax.servlet.jsp.JspException  ;
30  import javax.servlet.jsp.tagext.TagSupport  ;
31  import org.apache.struts.util.MessageResources;
32  import org.apache.struts.util.RequestUtils;
33  import org.apache.struts.taglib.TagUtils;
34  
35  /**
36   * Define the contents of a specified intra-application request as a
37   * page scope attribute of type <code>java.lang.String</code>.  If the
38   * current request is part of a session, the session identifier will be
39   * included in the generated request, so it will be part of the same
40   * session.
41   * <p>
42   * <strong>FIXME</strong>:  In a servlet 2.3 environment, we can use a
43   * wrapped response passed to RequestDispatcher.include().
44   *
45   * @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
46   */
47  
48  public class IncludeTag extends TagSupport   {
49  
50      // ------------------------------------------------------------- Properties
51  
52      /**
53       * Buffer size to use when reading the input stream.
54       */
55      protected static final int BUFFER_SIZE = 256;
56  
57      /**
58       * The anchor to be added to the end of the generated hyperlink.
59       */
60      protected String   anchor = null;
61  
62      public String   getAnchor() {
63          return (this.anchor);
64      }
65  
66      public void setAnchor(String   anchor) {
67          this.anchor = anchor;
68      }
69  
70      /**
71       * The name of the global <code>ActionForward</code> that contains a
72       * path to our requested resource.
73       */
74      protected String   forward = null;
75  
76      public String   getForward() {
77          return (this.forward);
78      }
79  
80      public void setForward(String   forward) {
81          this.forward = forward;
82      }
83  
84      /**
85       * The absolute URL to the resource to be included.
86       */
87      protected String   href = null;
88  
89      public String   getHref() {
90          return (this.href);
91      }
92  
93      public void setHref(String   href) {
94          this.href = href;
95      }
96  
97      /**
98       * The name of the scripting variable that will be exposed as a page
99       * scope attribute.
100      */
101     protected String   id = null;
102 
103     public String   getId() {
104         return (this.id);
105     }
106 
107     public void setId(String   id) {
108         this.id = id;
109     }
110 
111     /**
112      * The message resources for this package.
113      */
114     protected static MessageResources messages =
115         MessageResources.getMessageResources("org.apache.struts.taglib.bean.LocalStrings");
116 
117     /**
118      * Deprecated method to set the "name" attribute, which has been
119      * replaced by the "page" attribute.
120      *
121      * @deprecated use setPage(String) instead
122      */
123     public void setName(String   name) {
124         this.page = name;
125     }
126 
127     /**
128      * The context-relative URI of the page or servlet to be included.
129      */
130     protected String   page = null;
131 
132     public String   getPage() {
133         return (this.page);
134     }
135 
136     public void setPage(String   page) {
137         this.page = page;
138     }
139 
140     /**
141      * Include transaction token (if any) in the hyperlink?
142      */
143     protected boolean transaction = false;
144 
145     public boolean getTransaction() {
146         return (this.transaction);
147     }
148 
149     public void setTransaction(boolean transaction) {
150         this.transaction = transaction;
151     }
152     
153     protected boolean useLocalEncoding = false;
154     
155     public boolean isUseLocalEncoding() {
156         return useLocalEncoding;
157     }
158 
159     public void setUseLocalEncoding(boolean b) {
160         useLocalEncoding = b;
161     }
162 
163     // --------------------------------------------------------- Public Methods
164 
165     /**
166      * Define the contents returned for the specified resource as a
167      * page scope attribute.
168      *
169      * @exception JspException if a JSP error occurs
170      */
171     public int doStartTag() throws JspException   {
172 
173         // Set up a URLConnection to read the requested resource
174         Map   params =
175             TagUtils.getInstance().computeParameters(
176                 pageContext,
177                 null,
178                 null,
179                 null,
180                 null,
181                 null,
182                 null,
183                 null,
184                 transaction);
185         // FIXME - <html:link> attributes
186         String   urlString = null;
187         URL   url = null;
188         try {
189             urlString =
190                 TagUtils.getInstance().computeURLWithCharEncoding(pageContext, forward, href, page, null,null, params, anchor, false, useLocalEncoding);
191             if (urlString.indexOf(':') < 0) {
192                 HttpServletRequest   request = (HttpServletRequest  ) pageContext.getRequest();
193                 url = new URL  (RequestUtils.requestURL(request), urlString);
194             } else {
195                 url = new URL  (urlString);
196             }
197         } catch (MalformedURLException   e) {
198             TagUtils.getInstance().saveException(pageContext, e);
199             throw new JspException  (messages.getMessage("include.url", e.toString()));
200         }
201 
202         URLConnection   conn = null;
203         try {
204             // Set up the basic connection
205             conn = url.openConnection();
206             conn.setAllowUserInteraction(false);
207             conn.setDoInput(true);
208             conn.setDoOutput(false);
209             // Add a session id cookie if appropriate
210             HttpServletRequest   request = (HttpServletRequest  ) pageContext.getRequest();
211             addCookie(conn, urlString, request);
212             // Connect to the requested resource
213             conn.connect();
214         } catch (Exception   e) {
215             TagUtils.getInstance().saveException(pageContext, e);
216             throw new JspException  (
217                 messages.getMessage("include.open", url.toString(), e.toString()));
218         }
219 
220         // Copy the contents of this URL
221         StringBuffer   sb = new StringBuffer  ();
222         try {
223             BufferedInputStream   is = new BufferedInputStream  (conn.getInputStream());
224             InputStreamReader   in = new InputStreamReader  (is); // FIXME - encoding
225             char buffer[] = new char[BUFFER_SIZE];
226             int n = 0;
227             while (true) {
228                 n = in.read(buffer);
229                 if (n < 1)
230                     break;
231                 sb.append(buffer, 0, n);
232             }
233             in.close();
234         } catch (Exception   e) {
235             TagUtils.getInstance().saveException(pageContext, e);
236             throw new JspException  (
237                 messages.getMessage("include.read", url.toString(), e.toString()));
238         }
239 
240         // Define the retrieved content as a page scope attribute
241         pageContext.setAttribute(id, sb.toString());
242 
243         // Skip any body of this tag
244         return (SKIP_BODY);
245     }
246     /**
247      *  Add a session id cookie if appropriate. Can be overloaded to
248      *  support a cluster.
249      * @param conn
250      * @param urlString
251      * @param request
252      * @since Struts 1.2.0
253      */
254     protected void addCookie(URLConnection   conn, String   urlString, HttpServletRequest   request) {
255         if ((conn instanceof HttpURLConnection  )
256             && urlString.startsWith(request.getContextPath())
257             && (request.getRequestedSessionId() != null)
258             && request.isRequestedSessionIdFromCookie()) {
259             StringBuffer   sb = new StringBuffer  ("JSESSIONID=");
260             sb.append(request.getRequestedSessionId());
261             conn.setRequestProperty("Cookie", sb.toString());
262         }
263     }
264 
265     /**
266      * Release all allocated resources.
267      */
268     public void release() {
269         super.release();
270         anchor = null;
271         forward = null;
272         href = null;
273         id = null;
274         page = null;
275         transaction = false;
276     }    
277 
278 }
279
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags