Java > Open Source Codes > org > dbforms > util > PageContextBuffer


1 /*
2  * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/util/PageContextBuffer.java,v 1.10 2005/02/19 21:26:32 hkollmann Exp $
3  * $Revision: 1.10 $
4  * $Date: 2005/02/19 21:26:32 $
5  *
6  * DbForms - a Rapid Application Development Framework
7  * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
8  *
9  * This library is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22  */
23
24 /*
25  * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/util/PageContextBuffer.java,v 1.10 2005/02/19 21:26:32 hkollmann Exp $
26  * $Revision: 1.10 $
27  * $Date: 2005/02/19 21:26:32 $
28  *
29  */
30 package org.dbforms.util;
31
32 import java.io.BufferedReader ;
33 import java.io.IOException ;
34 import java.io.InputStream ;
35 import java.io.InputStreamReader ;
36
37 import java.util.Enumeration ;
38 import java.util.Hashtable ;
39
40 import javax.servlet.RequestDispatcher ;
41
42 /**
43  *
44  * read only PageContext.
45  *
46  * Used to generate a form via doStart internally to use the results.
47  *
48  * See StartReportServlet.
49  *
50  */
51 import javax.servlet.Servlet ;
52 import javax.servlet.ServletConfig ;
53 import javax.servlet.ServletContext ;
54 import javax.servlet.ServletException ;
55 import javax.servlet.ServletRequest ;
56 import javax.servlet.ServletResponse ;
57 import javax.servlet.http.HttpServletRequest ;
58 import javax.servlet.http.HttpSession ;
59 import javax.servlet.jsp.JspException ;
60 import javax.servlet.jsp.JspWriter ;
61 import javax.servlet.jsp.PageContext ;
62
63 /**
64  * DOCUMENT ME!
65  *
66  * @author $author$
67  * @version $Revision: 1.10 $
68  */
69 public class PageContextBuffer extends PageContext {
70     private Exception exception;
71
72     /**
73      * Provides programmatic access to the ExpressionEvaluator. The JSP
74      * Container must return a valid instance of an ExpressionEvaluator that can
75      * parse EL expressions.
76      */
77
78     // The expression evaluator, for evaluating EL expressions.
79 private org.apache.commons.el.ExpressionEvaluatorImpl elExprEval = new org.apache.commons.el.ExpressionEvaluatorImpl();
80
81     private Hashtable nametable;
82
83     private HttpSession session;
84
85     private JspWriterBuffer out;
86
87     private Servlet servlet;
88
89     private ServletConfig servletConfig;
90
91     private ServletContext servletContext;
92
93     private ServletRequest request;
94
95     private ServletResponse response;
96
97     private String errorPageURL;
98
99     // The variable resolver, for evaluating EL expressions.
100 private org.apache.commons.el.VariableResolverImpl variableResolver = new org.apache.commons.el.VariableResolverImpl(
101             this);
102
103     private boolean needsSession;
104
105     /**
106      * Creates a new PageContextDummy object.
107      */
108     public PageContextBuffer() {
109     }
110
111     /**
112      * DOCUMENT ME!
113      *
114      * @param name
115      * DOCUMENT ME!
116      * @param attribute
117      * DOCUMENT ME!
118      */
119     public void setAttribute(String name, Object attribute) {
120         if ((name == null) || (attribute == null)) {
121             throw new NullPointerException ();
122         }
123
124         nametable.put(name, attribute);
125     }
126
127     /**
128      * DOCUMENT ME!
129      *
130      * @param name
131      * DOCUMENT ME!
132      * @param attribute
133      * DOCUMENT ME!
134      * @param scope
135      * DOCUMENT ME!
136      */
137     public void setAttribute(String name, Object attribute, int scope) {
138         if ((name == null) || (attribute == null)) {
139             throw new NullPointerException ();
140         }
141
142         switch (scope) {
143         case APPLICATION_SCOPE:
144             break;
145
146         case PAGE_SCOPE:
147             setAttribute(name, attribute);
148
149             break;
150
151         case REQUEST_SCOPE:
152             break;
153
154         case SESSION_SCOPE:
155
156             if (!needsSession) {
157                 throw new IllegalArgumentException (
158                         "Invalid scope - Page does not participate in a session");
159             }
160
161             break;
162
163         default:
164             throw new IllegalArgumentException ("Invalid scope");
165         }
166     }
167
168     /**
169      * DOCUMENT ME!
170      *
171      * @param name
172      * DOCUMENT ME!
173      *
174      * @return DOCUMENT ME!
175      */
176     public Object getAttribute(String name) {
177         if (name == null) {
178             throw new IllegalArgumentException ();
179         }
180
181         return (nametable.get(name));
182     }
183
184     /**
185      * DOCUMENT ME!
186      *
187      * @param name
188      * DOCUMENT ME!
189      * @param scope
190      * DOCUMENT ME!
191      *
192      * @return DOCUMENT ME!
193      */
194     public Object getAttribute(String name, int scope) {
195         Object obj = null;
196
197         if (name == null) {
198             throw new NullPointerException ();
199         }
200
201         switch (scope) {
202         case PAGE_SCOPE:
203             obj = getAttribute(name);
204
205             break;
206
207         case REQUEST_SCOPE:
208             obj = request.getAttribute(name);
209
210             break;
211
212         case SESSION_SCOPE:
213
214             if (needsSession) {
215                 /* Throws IllegalStateException */
216                 obj = session.getAttribute(name);
217             } else {
218                 throw new IllegalArgumentException (
219                         "Invalid scope - Page does not participate in a session");
220             }
221
222             break;
223
224         case APPLICATION_SCOPE:
225             obj = servletContext.getAttribute(name);
226
227             break;
228
229         default:
230             throw new IllegalArgumentException ("Invalid scope");
231         }
232
233         return obj;
234     }
235
236     /**
237      * DOCUMENT ME!
238      *
239      * @param scope
240      * DOCUMENT ME!
241      *
242      * @return DOCUMENT ME!
243      */
244     public Enumeration getAttributeNamesInScope(int scope) {
245         switch (scope) {
246         case PAGE_SCOPE:
247             return nametable.keys();
248
249         case REQUEST_SCOPE:
250             return request.getAttributeNames();
251
252         case SESSION_SCOPE:
253
254             if (!needsSession) {
255                 throw new IllegalArgumentException (
256                         "Invalid scope - Page does not participate in a session");
257             }
258             /* HttpSession should have get/setAttributeNames too :) */
259             return session.getAttributeNames();
260
261         case APPLICATION_SCOPE:
262             return servletContext.getAttributeNames();
263
264         default:
265             throw new IllegalArgumentException ("Invalid scope");
266         }
267     }
268
269     /**
270      * DOCUMENT ME!
271      *
272      * @param name
273      * DOCUMENT ME!
274      *
275      * @return DOCUMENT ME!
276      */
277     public int getAttributesScope(String name) {
278         int scope = 0;
279
280         /* Search order - page, request, session (if supported), appl */
281         if (getAttribute(name, PAGE_SCOPE) != null) {
282             scope = PAGE_SCOPE;
283         }
284
285         if (getAttribute(name, REQUEST_SCOPE) != null) {
286             scope = REQUEST_SCOPE;
287         }
288
289         if (needsSession) {
290             if (getAttribute(name, SESSION_SCOPE) != null) {
291                 scope = SESSION_SCOPE;
292             }
293         }
294
295         if (getAttribute(name, APPLICATION_SCOPE) != null) {
296             scope = APPLICATION_SCOPE;
297         }
298
299         return scope;
300     }
301
302     /**
303      * DOCUMENT ME!
304      *
305      * @return DOCUMENT ME!
306      */
307     public StringBuffer getBuffer() {
308         return out.getBuffer();
309     }
310
311     /**
312      * DOCUMENT ME!
313      *
314      * @return DOCUMENT ME!
315      */
316     public Exception getException() {
317         return exception;
318     }
319
320     /**
321      * DOCUMENT ME!
322      *
323      * @return DOCUMENT ME!
324      */
325     public javax.servlet.jsp.el.ExpressionEvaluator getExpressionEvaluator() {
326         return elExprEval;
327     }
328
329     /**
330      * DOCUMENT ME!
331      *
332      * @return DOCUMENT ME!
333      */
334     public JspWriter getOut() {
335         return out;
336     }
337
338     /**
339      * DOCUMENT ME!
340      *
341      * @return DOCUMENT ME!
342      */
343     public Object getPage() {
344         return servlet;
345     }
346
347     /**
348      * DOCUMENT ME!
349      *
350      * @return DOCUMENT ME!
351      */
352     public ServletRequest getRequest() {
353         return request;
354     }
355
356     /**
357      * DOCUMENT ME!
358      *
359      * @return DOCUMENT ME!
360      */
361     public ServletResponse getResponse() {
362         return response;
363     }
364
365     /**
366      * DOCUMENT ME!
367      *
368      * @return DOCUMENT ME!
369      */
370     public String getResult() {
371         return out.getResult();
372     }
373
374     /**
375      * DOCUMENT ME!
376      *
377      * @return DOCUMENT ME!
378      */
379     public ServletConfig getServletConfig() {
380         return servletConfig;
381     }
382
383     /**
384      * DOCUMENT ME!
385      *
386      * @return DOCUMENT ME!
387      */
388     public ServletContext getServletContext() {
389         return servletContext;
390     }
391
392     /**
393      * DOCUMENT ME!
394      *
395      * @return DOCUMENT ME!
396      */
397     public HttpSession getSession() {
398         return session;
399     }
400
401     /**
402      * DOCUMENT ME!
403      *
404      * @return DOCUMENT ME!
405      */
406     public javax.servlet.jsp.el.VariableResolver getVariableResolver() {
407         return variableResolver;
408     }
409
410     /**
411      * DOCUMENT ME!
412      *
413      * @param name
414      * DOCUMENT ME!
415      *
416      * @return DOCUMENT ME!
417      */
418     public Object findAttribute(String name) {
419         Object obj = null;
420
421         /* Search order - page, request, session (if supported), appl */
422         if ((obj = getAttribute(name, PAGE_SCOPE)) != null) {
423             return obj;
424         }
425
426         if ((obj = getAttribute(name, REQUEST_SCOPE)) != null) {
427             return obj;
428         }
429
430         if (needsSession) {
431             if ((obj = getAttribute(name, SESSION_SCOPE)) != null) {
432                 return obj;
433             }
434         }
435
436         if ((obj = getAttribute(name, APPLICATION_SCOPE)) != null) {
437             return obj;
438         }
439
440         return obj;
441     }
442
443     /**
444      * DOCUMENT ME!
445      *
446      * @param relativeURLPath
447      * DOCUMENT ME!
448      *
449      * @throws ServletException
450      * DOCUMENT ME!
451      * @throws IOException
452      * DOCUMENT ME!
453      */
454     public void forward(String relativeURLPath) throws ServletException ,
455             IOException {
456         if (relativeURLPath == null) {
457             throw new ServletException (
458                     "[PageContext.forward()] Got 'null' URL - Probably caused "
459                             + "by a non-existent Request Time Attribute Value.");
460         }
461
462         String path = decodePath(relativeURLPath);
463
464         RequestDispatcher requestDispatcher = servletContext
465                 .getRequestDispatcher(path);
466
467         requestDispatcher.forward(request, response);
468     }
469
470     /**
471      * DOCUMENT ME!
472      *
473      * @param t
474      * DOCUMENT ME!
475      *
476      * @throws IOException
477      * DOCUMENT ME!
478      * @throws ServletException
479      * DOCUMENT ME!
480      */
481     public void handlePageException(Throwable t) throws IOException ,
482             ServletException {
483         // set the request attribute with the Throwable.
484 request.setAttribute("javax.servlet.jsp.jspException", t);
485
486         if ((errorPageURL != null) && !errorPageURL.equals("")) {
487             try {
488                 forward(errorPageURL);
489             } catch (IllegalStateException ise) {
490                 include(errorPageURL);
491             }
492         } else {
493             // Otherwise throw the exception wrapped inside a ServletException.
494 // Set the exception as the root cause in the ServletException
495 // to get a stack trace for the real problem
496 if (t instanceof IOException ) {
497                 throw (IOException ) t;
498             }
499
500             if (t instanceof ServletException ) {
501                 throw (ServletException ) t;
502             }
503
504             if (t instanceof RuntimeException ) {
505                 throw (RuntimeException ) t;
506             }
507
508             if (t instanceof JspException ) {
509                 Throwable rootCause = ((JspException ) t).getRootCause();
510
511                 if (rootCause != null) {
512                     throw new ServletException (t.getMessage(), rootCause);
513                 }
514                 throw new ServletException (t);
515             }
516
517             throw new ServletException (t);
518         }
519     }
520
521     /**
522      * DOCUMENT ME!
523      *
524      * @param e
525      * DOCUMENT ME!
526      *
527      * @throws ServletException
528      * DOCUMENT ME!
529      * @throws IOException
530      * DOCUMENT ME!
531      */
532     public void handlePageException(Exception e) throws ServletException ,
533             IOException {
534         // System.out.println("[PageContext] handling page exception");
535 // e.printStackTrace();
536 if (!errorPageURL.equals("")) {
537             setAttribute(EXCEPTION, e, REQUEST_SCOPE);
538             forward(errorPageURL);
539         } else {
540             System.out.println("Unhandled Page Exception:");
541             e.printStackTrace();
542             throw new ServletException ("An unhandled Page Exception occurred");
543         }
544     }
545
546     /**
547      * DOCUMENT ME!
548      *
549      * @param relativeURLPath
550      * DOCUMENT ME!
551      *
552      * @throws ServletException
553      * DOCUMENT ME!
554      * @throws IOException
555      * DOCUMENT ME!
556      */
557     public void include(String relativeURLPath) throws ServletException ,
558             IOException {
559         if (relativeURLPath == null) {
560             throw new ServletException (
561                     "[PageContext.include()] Got 'null' URL. Probably caused "
562                             + " by a non-existent Request Time Attribute Value.");
563         }
564
565         out.flush();
566
567         String path = decodePath(relativeURLPath);
568         RequestDispatcher requestDispatcher = servletContext
569                 .getRequestDispatcher(path);
570
571         if (requestDispatcher == null) {
572             InputStream is = servletContext
573                     .getResourceAsStream(relativeURLPath);
574
575             if (is == null) {
576                 throw new ServletException (
577                         "[PageContext.include()] Unable to obtain include resource "
578                                 + relativeURLPath);
579             }
580
581             BufferedReader in = new BufferedReader (new InputStreamReader (is));
582
583             try {
584                 int c;
585
586                 while ((c = in.read()) > 0) {
587                     out.write(c);
588                 }
589             } finally {
590                 in.close();
591             }
592         } else {
593             HttpServletRequest httpReq = (HttpServletRequest ) request;
594
595             /* Set additional attributes for include */
596             String attrib;
597
598             if ((attrib = httpReq.getRequestURI()) != null) {
599                 request.setAttribute("javax.servlet.include.request_uri",
600                         attrib);
601             }
602
603             if ((attrib = httpReq.getServletPath()) != null) {
604                 request.setAttribute("javax.servlet.include.servlet_path",
605                         attrib);
606             }
607
608             if ((attrib = httpReq.getPathInfo()) != null) {
609                 request.setAttribute("javax.servlet.include.path_info", attrib);
610             }
611
612             if ((attrib = httpReq.getQueryString()) != null) {
613                 request.setAttribute("javax.servlet.include.query_string",
614                         attrib);
615             }
616
617             requestDispatcher.include(request, response);
618         }
619     }
620
621     /**
622      * DOCUMENT ME!
623      *
624      * @param relativeURLPath
625      * DOCUMENT ME!
626      * @param flush
627      * DOCUMENT ME!
628      *
629      * @throws ServletException
630      * DOCUMENT ME!
631      * @throws IOException
632      * DOCUMENT ME!
633      */
634     public void include(String relativeURLPath, boolean flush)
635             throws ServletException , IOException {
636         include(relativeURLPath);
637         out.flush();
638     }
639
640     /**
641      * DOCUMENT ME!
642      *
643      * @param servlet
644      * DOCUMENT ME!
645      * @param request
646      * DOCUMENT ME!
647      * @param response
648      * DOCUMENT ME!
649      * @param errorPageURL
650      * DOCUMENT ME!
651      * @param needsSession
652      * DOCUMENT ME!
653      * @param bufferSize
654      * DOCUMENT ME!
655      * @param autoFlush
656      * DOCUMENT ME!
657      */
658     public void initialize(Servlet aservlet, ServletRequest arequest,
659             ServletResponse aresponse, String aerrorPageURL,
660             boolean aneedsSession, int bufferSize, boolean autoFlush) {
661         this.servlet = aservlet;
662         this.request = arequest;
663         this.response = aresponse;
664         this.errorPageURL = aerrorPageURL;
665         this.needsSession = aneedsSession;
666
667         if (needsSession) {
668             session = ((HttpServletRequest ) request).getSession();
669         }
670
671         nametable = new Hashtable ();
672         out = new JspWriterBuffer(bufferSize, autoFlush, response);
673         exception = null;
674
675         servletConfig = servlet.getServletConfig();
676         servletContext = servletConfig.getServletContext();
677     }
678
679     /**
680      * DOCUMENT ME!
681      */
682     public void release() {
683         this.servlet = null;
684         this.request = null;
685         this.response = null;
686         this.errorPageURL = null;
687
688         nametable = null;
689         out = null;
690         exception = null;
691
692         servletConfig = null;
693         servletContext = null;
694     }
695
696     /**
697      * DOCUMENT ME!
698      *
699      * @param name
700      * DOCUMENT ME!
701      */
702     public void removeAttribute(String name) {
703         nametable.remove(name);
704     }
705
706     /**
707      * DOCUMENT ME!
708      *
709      * @param name
710      * DOCUMENT ME!
711      * @param scope
712      * DOCUMENT ME!
713      */
714     public void removeAttribute(String name, int scope) {
715         switch (scope) {
716         case PAGE_SCOPE:
717             break;
718
719         case REQUEST_SCOPE:
720             throw new IllegalArgumentException (
721                     "Invalid scope - Can't remove attribute from REQUEST_SCOPE");
722
723         case SESSION_SCOPE:
724
725             if (!needsSession) {
726                 throw new IllegalArgumentException (
727                         "Invalid Scope - Page does not participate in an HTTP session");
728             }
729
730             break;
731
732         case APPLICATION_SCOPE:
733             break;
734
735         default:
736             throw new IllegalArgumentException ("Invalid Scope");
737         }
738     }
739
740     private String decodePath(String relativeURLPath) {
741         String path;
742
743         if (relativeURLPath.startsWith("/")) {
744             path = relativeURLPath;
745         } else {
746             path = ((HttpServletRequest ) request).getServletPath();
747             path = path.substring(0, path.lastIndexOf("/"));
748             path = path + "/" + relativeURLPath;
749         }
750
751         // System.out.println("[PageContext] Decoded path : " + path + "");
752 return path;
753     }
754 }
755

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