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1   // ========================================================================
2   // Copyright 2006 Mort Bay Consulting Pty. Ltd.
3   // ------------------------------------------------------------------------
4   // Licensed under the Apache License, Version 2.0 (the "License");
5   // you may not use this file except in compliance with the License.
6   // You may obtain a copy of the License at 
7   // http://www.apache.org/licenses/LICENSE-2.0
8   // Unless required by applicable law or agreed to in writing, software
9   // distributed under the License is distributed on an "AS IS" BASIS,
10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11  // See the License for the specific language governing permissions and
12  // limitations under the License.
13  // ========================================================================
14  
15  package org.mortbay.jetty.servlet;
16  
17  import java.io.IOException;
18  import java.util.ArrayList;
19  import java.util.HashMap;
20  import java.util.List;
21  import java.util.Map;
22  
23  import javax.servlet.ServletContext;
24  import javax.servlet.ServletException;
25  import javax.servlet.http.HttpServletRequest;
26  import javax.servlet.http.HttpServletResponse;
27  
28  import org.mortbay.jetty.HttpConnection;
29  import org.mortbay.jetty.HttpMethods;
30  import org.mortbay.jetty.handler.ContextHandler;
31  import org.mortbay.jetty.handler.ErrorHandler;
32  import org.mortbay.jetty.webapp.WebAppContext;
33  import org.mortbay.log.Log;
34  import org.mortbay.util.TypeUtil;
35  
36  /** Error Page Error Handler
37   * 
38   * An ErrorHandler that maps exceptions and status codes to URIs for dispatch using
39   * the internal ERROR style of dispatch.
40   * @author gregw
41   *
42   */
43  public class ErrorPageErrorHandler extends ErrorHandler
44  {
45      protected ServletContext _servletContext;
46      protected Map _errorPages; // code or exception to URL
47      protected List _errorPageList; // list of ErrorCode by range 
48  
49      /* ------------------------------------------------------------ */
50      /**
51       * @param context
52       */
53      public ErrorPageErrorHandler()
54      {}
55  
56      /* ------------------------------------------------------------ */
57      /* 
58       * @see org.mortbay.jetty.handler.ErrorHandler#handle(java.lang.String, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, int)
59       */
60      public void handle(String target, HttpServletRequest request, HttpServletResponse response, int dispatch) throws IOException
61      {
62          String method = request.getMethod();
63          if(!method.equals(HttpMethods.GET) && !method.equals(HttpMethods.POST) && !method.equals(HttpMethods.HEAD))
64          {
65              HttpConnection.getCurrentConnection().getRequest().setHandled(true);
66              return;
67          }
68          if (_errorPages!=null)
69          {
70              String error_page= null;
71              Class exClass= (Class)request.getAttribute(ServletHandler.__J_S_ERROR_EXCEPTION_TYPE);
72              
73              if (ServletException.class.equals(exClass))
74              {
75                  error_page= (String)_errorPages.get(exClass.getName());
76                  if (error_page == null)
77                  {
78                      Throwable th= (Throwable)request.getAttribute(ServletHandler.__J_S_ERROR_EXCEPTION);
79                      while (th instanceof ServletException)
80                          th= ((ServletException)th).getRootCause();
81                      if (th != null)
82                          exClass= th.getClass();
83                  }
84              }
85              
86              while (error_page == null && exClass != null )
87              {
88                  error_page= (String)_errorPages.get(exClass.getName());
89                  exClass= exClass.getSuperclass();
90              }
91              
92              if (error_page == null)
93              {
94                  // look for an exact code match
95                  Integer code=(Integer)request.getAttribute(ServletHandler.__J_S_ERROR_STATUS_CODE);
96                  if (code!=null)
97                  {
98                      error_page= (String)_errorPages.get(TypeUtil.toString(code.intValue()));
99  
100                     // if still not found
101                     if ((error_page == null) && (_errorPageList != null))
102                     {
103                         // look for an error code range match.
104                         for (int i = 0; i < _errorPageList.size(); i++)
105                         {
106                             ErrorCodeRange errCode = (ErrorCodeRange) _errorPageList.get(i);
107                             if (errCode.isInRange(code.intValue()))
108                             {
109                                 error_page = errCode.getUri();
110                                 break;
111                             }
112                         }
113                     }
114                 }
115             }
116             
117             if (error_page!=null)
118             {
119                 String old_error_page=(String)request.getAttribute(WebAppContext.ERROR_PAGE);
120                 if (old_error_page==null || !old_error_page.equals(error_page))
121                 {
122                     request.setAttribute(WebAppContext.ERROR_PAGE, error_page);
123                     
124                     Dispatcher dispatcher = (Dispatcher) _servletContext.getRequestDispatcher(error_page);
125                     try
126                     {
127                         if(dispatcher!=null)
128                         {    
129                             dispatcher.error(request, response);
130                             return;
131                         }
132                         else
133                         {
134                             Log.warn("No error page "+error_page);
135                         }
136                     }
137                     catch (ServletException e)
138                     {
139                         Log.warn(Log.EXCEPTION, e);
140                         return;
141                     }
142                 }
143             }
144         }
145         
146         super.handle(target, request, response, dispatch);
147     }
148 
149     /* ------------------------------------------------------------ */
150     /**
151      * @return Returns the errorPages.
152      */
153     public Map getErrorPages()
154     {
155         return _errorPages;
156     }
157     
158     /* ------------------------------------------------------------ */
159     /**
160      * @param errorPages The errorPages to set. A map of Exception class name  or error code as a string to URI string
161      */
162     public void setErrorPages(Map errorPages)
163     {
164         _errorPages = errorPages;
165     }
166 
167     /* ------------------------------------------------------------ */
168     /** Add Error Page mapping for an exception class
169      * This method is called as a result of an exception-type element in a web.xml file
170      * or may be called directly
171      * @param code The class (or superclass) of the matching exceptions
172      * @param uri The URI of the error page.
173      */
174     public void addErrorPage(Class exception,String uri)
175     {
176         if (_errorPages==null)
177             _errorPages=new HashMap();
178         _errorPages.put(exception.getName(),uri);
179     }
180     
181     /* ------------------------------------------------------------ */
182     /** Add Error Page mapping for a status code.
183      * This method is called as a result of an error-code element in a web.xml file
184      * or may be called directly
185      * @param code The HTTP status code to match
186      * @param uri The URI of the error page.
187      */
188     public void addErrorPage(int code,String uri)
189     {
190         if (_errorPages==null)
191             _errorPages=new HashMap();
192         _errorPages.put(TypeUtil.toString(code),uri);
193     }
194     
195     /* ------------------------------------------------------------ */
196     /** Add Error Page mapping for a status code range.
197      * This method is not available from web.xml and must be called
198      * directly.
199      * @param from The lowest matching status code
200      * @param to The highest matching status code
201      * @param uri The URI of the error page.
202      */
203     public void addErrorPage(int from, int to, String uri)
204     {
205         if (_errorPageList == null)
206         {
207             _errorPageList = new ArrayList();
208         }
209         _errorPageList.add(new ErrorCodeRange(from, to, uri));
210     }
211 
212     /* ------------------------------------------------------------ */
213     protected void doStart() throws Exception
214     {
215         super.doStart();
216         _servletContext=ContextHandler.getCurrentContext();
217     }
218 
219     /* ------------------------------------------------------------ */
220     protected void doStop() throws Exception
221     {
222         // TODO Auto-generated method stub
223         super.doStop();
224     }
225 
226     /* ------------------------------------------------------------ */
227     /* ------------------------------------------------------------ */
228     private class ErrorCodeRange
229     {
230         private int _from;
231         private int _to;
232         private String _uri;
233         
234         ErrorCodeRange(int from, int to, String uri)
235             throws IllegalArgumentException
236         {
237             if (from > to)
238                 throw new IllegalArgumentException("from>to");
239             
240             _from = from;
241             _to = to;
242             _uri = uri;
243         }
244         
245         boolean isInRange(int value)
246         {
247             if ((value >= _from) && (value <= _to))
248             {
249                 return true;
250             }
251             
252             return false;
253         }
254         
255         String getUri()
256         {
257             return _uri;
258         }
259         
260         public String toString()
261         {
262             return "from: " + _from + ",to: " + _to + ",uri: " + _uri;
263         }
264     }    
265 }