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1   /*
2   * Copyright 2004 The Apache Software Foundation
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   *
8   *     http://www.apache.org/licenses/LICENSE-2.0
9   *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16  package javax.servlet.http;
17  
18  import java.io.IOException;
19  
20  import javax.servlet.ServletResponse;
21  
22  /**
23   *
24   * Extends the {@link ServletResponse} interface to provide HTTP-specific
25   * functionality in sending a response.  For example, it has methods
26   * to access HTTP headers and cookies.
27   *
28   * <p>The servlet container creates an <code>HttpServletResponse</code> object
29   * and passes it as an argument to the servlet's service methods
30   * (<code>doGet</code>, <code>doPost</code>, etc).
31   *
32   * 
33   * @author	Various
34   * @version	$Version$
35   *
36   * @see		javax.servlet.ServletResponse
37   *
38   */
39  
40  
41  
42  public interface HttpServletResponse extends ServletResponse {
43  
44      /**
45       * Adds the specified cookie to the response.  This method can be called
46       * multiple times to set more than one cookie.
47       *
48       * @param cookie the Cookie to return to the client
49       *
50       */
51  
52      public void addCookie(Cookie cookie);
53  
54      /**
55       * Returns a boolean indicating whether the named response header 
56       * has already been set.
57       * 
58       * @param	name	the header name
59       * @return		<code>true</code> if the named response header 
60       *			has already been set; 
61       * 			<code>false</code> otherwise
62       */
63  
64      public boolean containsHeader(String name);
65  
66      /**
67       * Encodes the specified URL by including the session ID in it,
68       * or, if encoding is not needed, returns the URL unchanged.
69       * The implementation of this method includes the logic to
70       * determine whether the session ID needs to be encoded in the URL.
71       * For example, if the browser supports cookies, or session
72       * tracking is turned off, URL encoding is unnecessary.
73       * 
74       * <p>For robust session tracking, all URLs emitted by a servlet 
75       * should be run through this
76       * method.  Otherwise, URL rewriting cannot be used with browsers
77       * which do not support cookies.
78       *
79       * @param	url	the url to be encoded.
80       * @return		the encoded URL if encoding is needed;
81       * 			the unchanged URL otherwise.
82       */
83  
84      public String encodeURL(String url);
85  
86      /**
87       * Encodes the specified URL for use in the
88       * <code>sendRedirect</code> method or, if encoding is not needed,
89       * returns the URL unchanged.  The implementation of this method
90       * includes the logic to determine whether the session ID
91       * needs to be encoded in the URL.  Because the rules for making
92       * this determination can differ from those used to decide whether to
93       * encode a normal link, this method is separated from the
94       * <code>encodeURL</code> method.
95       * 
96       * <p>All URLs sent to the <code>HttpServletResponse.sendRedirect</code>
97       * method should be run through this method.  Otherwise, URL
98       * rewriting cannot be used with browsers which do not support
99       * cookies.
100      *
101      * @param	url	the url to be encoded.
102      * @return		the encoded URL if encoding is needed;
103      * 			the unchanged URL otherwise.
104      *
105      * @see #sendRedirect
106      * @see #encodeUrl
107      */
108 
109     public String encodeRedirectURL(String url);
110 
111     /**
112      * @deprecated	As of version 2.1, use encodeURL(String url) instead
113      *
114      * @param	url	the url to be encoded.
115      * @return		the encoded URL if encoding is needed; 
116      * 			the unchanged URL otherwise.
117      */
118 
119     public String encodeUrl(String url);
120     
121     /**
122      * @deprecated	As of version 2.1, use 
123      *			encodeRedirectURL(String url) instead
124      *
125      * @param	url	the url to be encoded.
126      * @return		the encoded URL if encoding is needed; 
127      * 			the unchanged URL otherwise.
128      */
129 
130     public String encodeRedirectUrl(String url);
131 
132     /**
133      * Sends an error response to the client using the specified
134      * status.  The server defaults to creating the
135      * response to look like an HTML-formatted server error page
136      * containing the specified message, setting the content type
137      * to "text/html", leaving cookies and other headers unmodified.
138      *
139      * If an error-page declaration has been made for the web application
140      * corresponding to the status code passed in, it will be served back in 
141      * preference to the suggested msg parameter. 
142      *
143      * <p>If the response has already been committed, this method throws 
144      * an IllegalStateException.
145      * After using this method, the response should be considered
146      * to be committed and should not be written to.
147      *
148      * @param	sc	the error status code
149      * @param	msg	the descriptive message
150      * @exception	IOException	If an input or output exception occurs
151      * @exception	IllegalStateException	If the response was committed
152      */
153    
154     public void sendError(int sc, String msg) throws IOException;
155 
156     /**
157      * Sends an error response to the client using the specified status
158      * code and clearing the buffer. 
159      * <p>If the response has already been committed, this method throws 
160      * an IllegalStateException.
161      * After using this method, the response should be considered
162      * to be committed and should not be written to.
163      *
164      * @param	sc	the error status code
165      * @exception	IOException	If an input or output exception occurs
166      * @exception	IllegalStateException	If the response was committed
167      *						before this method call
168      */
169 
170     public void sendError(int sc) throws IOException;
171 
172     /**
173      * Sends a temporary redirect response to the client using the
174      * specified redirect location URL.  This method can accept relative URLs;
175      * the servlet container must convert the relative URL to an absolute URL
176      * before sending the response to the client. If the location is relative 
177      * without a leading '/' the container interprets it as relative to
178      * the current request URI. If the location is relative with a leading
179      * '/' the container interprets it as relative to the servlet container root.
180      *
181      * <p>If the response has already been committed, this method throws 
182      * an IllegalStateException.
183      * After using this method, the response should be considered
184      * to be committed and should not be written to.
185      *
186      * @param		location	the redirect location URL
187      * @exception	IOException	If an input or output exception occurs
188      * @exception	IllegalStateException	If the response was committed or
189  if a partial URL is given and cannot be converted into a valid URL
190      */
191 
192     public void sendRedirect(String location) throws IOException;
193     
194     /**
195      * 
196      * Sets a response header with the given name and
197      * date-value.  The date is specified in terms of
198      * milliseconds since the epoch.  If the header had already
199      * been set, the new value overwrites the previous one.  The
200      * <code>containsHeader</code> method can be used to test for the
201      * presence of a header before setting its value.
202      * 
203      * @param	name	the name of the header to set
204      * @param	date	the assigned date value
205      * 
206      * @see #containsHeader
207      * @see #addDateHeader
208      */
209 
210     public void setDateHeader(String name, long date);
211     
212     /**
213      * 
214      * Adds a response header with the given name and
215      * date-value.  The date is specified in terms of
216      * milliseconds since the epoch.  This method allows response headers 
217      * to have multiple values.
218      * 
219      * @param	name	the name of the header to set
220      * @param	date	the additional date value
221      * 
222      * @see #setDateHeader
223      */
224 
225     public void addDateHeader(String name, long date);
226     
227     /**
228      *
229      * Sets a response header with the given name and value.
230      * If the header had already been set, the new value overwrites the
231      * previous one.  The <code>containsHeader</code> method can be
232      * used to test for the presence of a header before setting its
233      * value.
234      * 
235      * @param	name	the name of the header
236      * @param	value	the header value  If it contains octet string,
237      *		it should be encoded according to RFC 2047
238      *		(http://www.ietf.org/rfc/rfc2047.txt)
239      *
240      * @see #containsHeader
241      * @see #addHeader
242      */
243 
244     public void setHeader(String name, String value);
245     
246     /**
247      * Adds a response header with the given name and value.
248      * This method allows response headers to have multiple values.
249      * 
250      * @param	name	the name of the header
251      * @param	value	the additional header value   If it contains
252      *		octet string, it should be encoded
253      *		according to RFC 2047
254      *		(http://www.ietf.org/rfc/rfc2047.txt)
255      *
256      * @see #setHeader
257      */
258 
259     public void addHeader(String name, String value);
260 
261     /**
262      * Sets a response header with the given name and
263      * integer value.  If the header had already been set, the new value
264      * overwrites the previous one.  The <code>containsHeader</code>
265      * method can be used to test for the presence of a header before
266      * setting its value.
267      *
268      * @param	name	the name of the header
269      * @param	value	the assigned integer value
270      *
271      * @see #containsHeader
272      * @see #addIntHeader
273      */
274 
275     public void setIntHeader(String name, int value);
276 
277     /**
278      * Adds a response header with the given name and
279      * integer value.  This method allows response headers to have multiple
280      * values.
281      *
282      * @param	name	the name of the header
283      * @param	value	the assigned integer value
284      *
285      * @see #setIntHeader
286      */
287 
288     public void addIntHeader(String name, int value);
289 
290 
291     
292     /**
293      * Sets the status code for this response.  This method is used to
294      * set the return status code when there is no error (for example,
295      * for the status codes SC_OK or SC_MOVED_TEMPORARILY).  If there
296      * is an error, and the caller wishes to invoke an error-page defined
297      * in the web application, the <code>sendError</code> method should be used
298      * instead.
299      * <p> The container clears the buffer and sets the Location header, preserving
300      * cookies and other headers.
301      *
302      * @param	sc	the status code
303      *
304      * @see #sendError
305      */
306 
307     public void setStatus(int sc);
308   
309     /**
310      * @deprecated As of version 2.1, due to ambiguous meaning of the 
311      * message parameter. To set a status code 
312      * use <code>setStatus(int)</code>, to send an error with a description
313      * use <code>sendError(int, String)</code>.
314      *
315      * Sets the status code and message for this response.
316      * 
317      * @param	sc	the status code
318      * @param	sm	the status message
319      */
320 
321     public void setStatus(int sc, String sm);
322 
323     
324     /*
325      * Server status codes; see RFC 2068.
326      */
327 
328     /**
329      * Status code (100) indicating the client can continue.
330      */
331 
332     public static final int SC_CONTINUE = 100;
333 
334     
335     /**
336      * Status code (101) indicating the server is switching protocols
337      * according to Upgrade header.
338      */
339 
340     public static final int SC_SWITCHING_PROTOCOLS = 101;
341 
342     /**
343      * Status code (200) indicating the request succeeded normally.
344      */
345 
346     public static final int SC_OK = 200;
347 
348     /**
349      * Status code (201) indicating the request succeeded and created
350      * a new resource on the server.
351      */
352 
353     public static final int SC_CREATED = 201;
354 
355     /**
356      * Status code (202) indicating that a request was accepted for
357      * processing, but was not completed.
358      */
359 
360     public static final int SC_ACCEPTED = 202;
361 
362     /**
363      * Status code (203) indicating that the meta information presented
364      * by the client did not originate from the server.
365      */
366 
367     public static final int SC_NON_AUTHORITATIVE_INFORMATION = 203;
368 
369     /**
370      * Status code (204) indicating that the request succeeded but that
371      * there was no new information to return.
372      */
373 
374     public static final int SC_NO_CONTENT = 204;
375 
376     /**
377      * Status code (205) indicating that the agent <em>SHOULD</em> reset
378      * the document view which caused the request to be sent.
379      */
380 
381     public static final int SC_RESET_CONTENT = 205;
382 
383     /**
384      * Status code (206) indicating that the server has fulfilled
385      * the partial GET request for the resource.
386      */
387 
388     public static final int SC_PARTIAL_CONTENT = 206;
389 
390     /**
391      * Status code (300) indicating that the requested resource
392      * corresponds to any one of a set of representations, each with
393      * its own specific location.
394      */
395 
396     public static final int SC_MULTIPLE_CHOICES = 300;
397 
398     /**
399      * Status code (301) indicating that the resource has permanently
400      * moved to a new location, and that future references should use a
401      * new URI with their requests.
402      */
403 
404     public static final int SC_MOVED_PERMANENTLY = 301;
405 
406     /**
407      * Status code (302) indicating that the resource has temporarily
408      * moved to another location, but that future references should
409      * still use the original URI to access the resource.
410      *
411      * This definition is being retained for backwards compatibility.
412      * SC_FOUND is now the preferred definition.
413      */
414 
415     public static final int SC_MOVED_TEMPORARILY = 302;
416 
417     /**
418     * Status code (302) indicating that the resource reside
419     * temporarily under a different URI. Since the redirection might
420     * be altered on occasion, the client should continue to use the
421     * Request-URI for future requests.(HTTP/1.1) To represent the
422     * status code (302), it is recommended to use this variable.
423     */
424 
425     public static final int SC_FOUND = 302;
426 
427     /**
428      * Status code (303) indicating that the response to the request
429      * can be found under a different URI.
430      */
431 
432     public static final int SC_SEE_OTHER = 303;
433 
434     /**
435      * Status code (304) indicating that a conditional GET operation
436      * found that the resource was available and not modified.
437      */
438 
439     public static final int SC_NOT_MODIFIED = 304;
440 
441     /**
442      * Status code (305) indicating that the requested resource
443      * <em>MUST</em> be accessed through the proxy given by the
444      * <code><em>Location</em></code> field.
445      */
446 
447     public static final int SC_USE_PROXY = 305;
448 
449      /**
450      * Status code (307) indicating that the requested resource 
451      * resides temporarily under a different URI. The temporary URI
452      * <em>SHOULD</em> be given by the <code><em>Location</em></code> 
453      * field in the response.
454      */
455 
456      public static final int SC_TEMPORARY_REDIRECT = 307;
457 
458     /**
459      * Status code (400) indicating the request sent by the client was
460      * syntactically incorrect.
461      */
462 
463     public static final int SC_BAD_REQUEST = 400;
464 
465     /**
466      * Status code (401) indicating that the request requires HTTP
467      * authentication.
468      */
469 
470     public static final int SC_UNAUTHORIZED = 401;
471 
472     /**
473      * Status code (402) reserved for future use.
474      */
475 
476     public static final int SC_PAYMENT_REQUIRED = 402;
477 
478     /**
479      * Status code (403) indicating the server understood the request
480      * but refused to fulfill it.
481      */
482 
483     public static final int SC_FORBIDDEN = 403;
484 
485     /**
486      * Status code (404) indicating that the requested resource is not
487      * available.
488      */
489 
490     public static final int SC_NOT_FOUND = 404;
491 
492     /**
493      * Status code (405) indicating that the method specified in the
494      * <code><em>Request-Line</em></code> is not allowed for the resource
495      * identified by the <code><em>Request-URI</em></code>.
496      */
497 
498     public static final int SC_METHOD_NOT_ALLOWED = 405;
499 
500     /**
501      * Status code (406) indicating that the resource identified by the
502      * request is only capable of generating response entities which have
503      * content characteristics not acceptable according to the accept
504      * headers sent in the request.
505      */
506 
507     public static final int SC_NOT_ACCEPTABLE = 406;
508 
509     /**
510      * Status code (407) indicating that the client <em>MUST</em> first
511      * authenticate itself with the proxy.
512      */
513 
514     public static final int SC_PROXY_AUTHENTICATION_REQUIRED = 407;
515 
516     /**
517      * Status code (408) indicating that the client did not produce a
518      * request within the time that the server was prepared to wait.
519      */
520 
521     public static final int SC_REQUEST_TIMEOUT = 408;
522 
523     /**
524      * Status code (409) indicating that the request could not be
525      * completed due to a conflict with the current state of the
526      * resource.
527      */
528 
529     public static final int SC_CONFLICT = 409;
530 
531     /**
532      * Status code (410) indicating that the resource is no longer
533      * available at the server and no forwarding address is known.
534      * This condition <em>SHOULD</em> be considered permanent.
535      */
536 
537     public static final int SC_GONE = 410;
538 
539     /**
540      * Status code (411) indicating that the request cannot be handled
541      * without a defined <code><em>Content-Length</em></code>.
542      */
543 
544     public static final int SC_LENGTH_REQUIRED = 411;
545 
546     /**
547      * Status code (412) indicating that the precondition given in one
548      * or more of the request-header fields evaluated to false when it
549      * was tested on the server.
550      */
551 
552     public static final int SC_PRECONDITION_FAILED = 412;
553 
554     /**
555      * Status code (413) indicating that the server is refusing to process
556      * the request because the request entity is larger than the server is
557      * willing or able to process.
558      */
559 
560     public static final int SC_REQUEST_ENTITY_TOO_LARGE = 413;
561 
562     /**
563      * Status code (414) indicating that the server is refusing to service
564      * the request because the <code><em>Request-URI</em></code> is longer
565      * than the server is willing to interpret.
566      */
567 
568     public static final int SC_REQUEST_URI_TOO_LONG = 414;
569 
570     /**
571      * Status code (415) indicating that the server is refusing to service
572      * the request because the entity of the request is in a format not
573      * supported by the requested resource for the requested method.
574      */
575 
576     public static final int SC_UNSUPPORTED_MEDIA_TYPE = 415;
577 
578     /**
579      * Status code (416) indicating that the server cannot serve the
580      * requested byte range.
581      */
582 
583     public static final int SC_REQUESTED_RANGE_NOT_SATISFIABLE = 416;
584 
585     /**
586      * Status code (417) indicating that the server could not meet the
587      * expectation given in the Expect request header.
588      */
589 
590     public static final int SC_EXPECTATION_FAILED = 417;
591 
592     /**
593      * Status code (500) indicating an error inside the HTTP server
594      * which prevented it from fulfilling the request.
595      */
596 
597     public static final int SC_INTERNAL_SERVER_ERROR = 500;
598 
599     /**
600      * Status code (501) indicating the HTTP server does not support
601      * the functionality needed to fulfill the request.
602      */
603 
604     public static final int SC_NOT_IMPLEMENTED = 501;
605 
606     /**
607      * Status code (502) indicating that the HTTP server received an
608      * invalid response from a server it consulted when acting as a
609      * proxy or gateway.
610      */
611 
612     public static final int SC_BAD_GATEWAY = 502;
613 
614     /**
615      * Status code (503) indicating that the HTTP server is
616      * temporarily overloaded, and unable to handle the request.
617      */
618 
619     public static final int SC_SERVICE_UNAVAILABLE = 503;
620 
621     /**
622      * Status code (504) indicating that the server did not receive
623      * a timely response from the upstream server while acting as
624      * a gateway or proxy.
625      */
626 
627     public static final int SC_GATEWAY_TIMEOUT = 504;
628 
629     /**
630      * Status code (505) indicating that the server does not support
631      * or refuses to support the HTTP protocol version that was used
632      * in the request message.
633      */
634 
635     public static final int SC_HTTP_VERSION_NOT_SUPPORTED = 505;
636 }