HttpServletResponse


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2   * Licensed to the Apache Software Foundation (ASF) under one or more
3   * contributor license agreements.  See the NOTICE file distributed with
4   * this work for additional information regarding copyright ownership.
5   * The ASF licenses this file to You under the Apache License, Version 2.0
6   * (the "License"); you may not use this file except in compliance with
7   * the License.  You may obtain a copy of the License at
8   *
9   *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17  package javax.servlet.http;
18  
19  import java.io.IOException  ;
20  
21  import javax.servlet.ServletResponse  ;
22  
23  /**
24   *
25   * Extends the {@link ServletResponse} interface to provide HTTP-specific
26   * functionality in sending a response.  For example, it has methods
27   * to access HTTP headers and cookies.
28   *
29   * <p>The servlet container creates an <code>HttpServletResponse</code> object
30   * and passes it as an argument to the servlet's service methods
31   * (<code>doGet</code>, <code>doPost</code>, etc).
32   *
33   * 
34   * @author  Various
35   * @version $Version$
36   *
37   * @see     javax.servlet.ServletResponse
38   *
39   */
40  
41  
42  
43  public interface HttpServletResponse extends ServletResponse   {
44  
45      /**
46       * Adds the specified cookie to the response.  This method can be called
47       * multiple times to set more than one cookie.
48       *
49       * @param cookie the Cookie to return to the client
50       *
51       */
52  
53      public void addCookie(Cookie   cookie);
54  
55      /**
56       * Returns a boolean indicating whether the named response header 
57       * has already been set.
58       * 
59       * @param   name    the header name
60       * @return      <code>true</code> if the named response header 
61       *          has already been set; 
62       *          <code>false</code> otherwise
63       */
64  
65      public boolean containsHeader(String   name);
66  
67      /**
68       * Encodes the specified URL by including the session ID in it,
69       * or, if encoding is not needed, returns the URL unchanged.
70       * The implementation of this method includes the logic to
71       * determine whether the session ID needs to be encoded in the URL.
72       * For example, if the browser supports cookies, or session
73       * tracking is turned off, URL encoding is unnecessary.
74       * 
75       * <p>For robust session tracking, all URLs emitted by a servlet 
76       * should be run through this
77       * method.  Otherwise, URL rewriting cannot be used with browsers
78       * which do not support cookies.
79       *
80       * @param   url the url to be encoded.
81       * @return      the encoded URL if encoding is needed;
82       *          the unchanged URL otherwise.
83       */
84  
85      public String   encodeURL(String   url);
86  
87      /**
88       * Encodes the specified URL for use in the
89       * <code>sendRedirect</code> method or, if encoding is not needed,
90       * returns the URL unchanged.  The implementation of this method
91       * includes the logic to determine whether the session ID
92       * needs to be encoded in the URL.  Because the rules for making
93       * this determination can differ from those used to decide whether to
94       * encode a normal link, this method is separated from the
95       * <code>encodeURL</code> method.
96       * 
97       * <p>All URLs sent to the <code>HttpServletResponse.sendRedirect</code>
98       * method should be run through this method.  Otherwise, URL
99       * rewriting cannot be used with browsers which do not support
100      * cookies.
101      *
102      * @param   url the url to be encoded.
103      * @return      the encoded URL if encoding is needed;
104      *          the unchanged URL otherwise.
105      *
106      * @see #sendRedirect
107      * @see #encodeUrl
108      */
109 
110     public String   encodeRedirectURL(String   url);
111 
112     /**
113      * @deprecated  As of version 2.1, use encodeURL(String url) instead
114      *
115      * @param   url the url to be encoded.
116      * @return      the encoded URL if encoding is needed; 
117      *          the unchanged URL otherwise.
118      */
119 
120     public String   encodeUrl(String   url);
121     
122     /**
123      * @deprecated  As of version 2.1, use 
124      *          encodeRedirectURL(String url) instead
125      *
126      * @param   url the url to be encoded.
127      * @return      the encoded URL if encoding is needed; 
128      *          the unchanged URL otherwise.
129      */
130 
131     public String   encodeRedirectUrl(String   url);
132 
133     /**
134      * Sends an error response to the client using the specified
135      * status.  The server defaults to creating the
136      * response to look like an HTML-formatted server error page
137      * containing the specified message, setting the content type
138      * to "text/html", leaving cookies and other headers unmodified.
139      *
140      * If an error-page declaration has been made for the web application
141      * corresponding to the status code passed in, it will be served back in 
142      * preference to the suggested msg parameter. 
143      *
144      * <p>If the response has already been committed, this method throws 
145      * an IllegalStateException.
146      * After using this method, the response should be considered
147      * to be committed and should not be written to.
148      *
149      * @param   sc  the error status code
150      * @param   msg the descriptive message
151      * @exception   IOException If an input or output exception occurs
152      * @exception   IllegalStateException   If the response was committed
153      */
154    
155     public void sendError(int sc, String   msg) throws IOException  ;
156 
157     /**
158      * Sends an error response to the client using the specified status
159      * code and clearing the buffer. 
160      * <p>If the response has already been committed, this method throws 
161      * an IllegalStateException.
162      * After using this method, the response should be considered
163      * to be committed and should not be written to.
164      *
165      * @param   sc  the error status code
166      * @exception   IOException If an input or output exception occurs
167      * @exception   IllegalStateException   If the response was committed
168      *                      before this method call
169      */
170 
171     public void sendError(int sc) throws IOException  ;
172 
173     /**
174      * Sends a temporary redirect response to the client using the
175      * specified redirect location URL.  This method can accept relative URLs;
176      * the servlet container must convert the relative URL to an absolute URL
177      * before sending the response to the client. If the location is relative 
178      * without a leading '/' the container interprets it as relative to
179      * the current request URI. If the location is relative with a leading
180      * '/' the container interprets it as relative to the servlet container root.
181      *
182      * <p>If the response has already been committed, this method throws 
183      * an IllegalStateException.
184      * After using this method, the response should be considered
185      * to be committed and should not be written to.
186      *
187      * @param       location    the redirect location URL
188      * @exception   IOException If an input or output exception occurs
189      * @exception   IllegalStateException   If the response was committed or
190  if a partial URL is given and cannot be converted into a valid URL
191      */
192 
193     public void sendRedirect(String   location) throws IOException  ;
194     
195     /**
196      * 
197      * Sets a response header with the given name and
198      * date-value.  The date is specified in terms of
199      * milliseconds since the epoch.  If the header had already
200      * been set, the new value overwrites the previous one.  The
201      * <code>containsHeader</code> method can be used to test for the
202      * presence of a header before setting its value.
203      * 
204      * @param   name    the name of the header to set
205      * @param   date    the assigned date value
206      * 
207      * @see #containsHeader
208      * @see #addDateHeader
209      */
210 
211     public void setDateHeader(String   name, long date);
212     
213     /**
214      * 
215      * Adds a response header with the given name and
216      * date-value.  The date is specified in terms of
217      * milliseconds since the epoch.  This method allows response headers 
218      * to have multiple values.
219      * 
220      * @param   name    the name of the header to set
221      * @param   date    the additional date value
222      * 
223      * @see #setDateHeader
224      */
225 
226     public void addDateHeader(String   name, long date);
227     
228     /**
229      *
230      * Sets a response header with the given name and value.
231      * If the header had already been set, the new value overwrites the
232      * previous one.  The <code>containsHeader</code> method can be
233      * used to test for the presence of a header before setting its
234      * value.
235      * 
236      * @param   name    the name of the header
237      * @param   value   the header value  If it contains octet string,
238      *      it should be encoded according to RFC 2047
239      *      (http://www.ietf.org/rfc/rfc2047.txt)
240      *
241      * @see #containsHeader
242      * @see #addHeader
243      */
244 
245     public void setHeader(String   name, String   value);
246     
247     /**
248      * Adds a response header with the given name and value.
249      * This method allows response headers to have multiple values.
250      * 
251      * @param   name    the name of the header
252      * @param   value   the additional header value   If it contains
253      *      octet string, it should be encoded
254      *      according to RFC 2047
255      *      (http://www.ietf.org/rfc/rfc2047.txt)
256      *
257      * @see #setHeader
258      */
259 
260     public void addHeader(String   name, String   value);
261 
262     /**
263      * Sets a response header with the given name and
264      * integer value.  If the header had already been set, the new value
265      * overwrites the previous one.  The <code>containsHeader</code>
266      * method can be used to test for the presence of a header before
267      * setting its value.
268      *
269      * @param   name    the name of the header
270      * @param   value   the assigned integer value
271      *
272      * @see #containsHeader
273      * @see #addIntHeader
274      */
275 
276     public void setIntHeader(String   name, int value);
277 
278     /**
279      * Adds a response header with the given name and
280      * integer value.  This method allows response headers to have multiple
281      * values.
282      *
283      * @param   name    the name of the header
284      * @param   value   the assigned integer value
285      *
286      * @see #setIntHeader
287      */
288 
289     public void addIntHeader(String   name, int value);
290 
291 
292     
293     /**
294      * Sets the status code for this response.  This method is used to
295      * set the return status code when there is no error (for example,
296      * for the status codes SC_OK or SC_MOVED_TEMPORARILY).  If there
297      * is an error, and the caller wishes to invoke an error-page defined
298      * in the web application, the <code>sendError</code> method should be used
299      * instead.
300      * <p> The container clears the buffer and sets the Location header, preserving
301      * cookies and other headers.
302      *
303      * @param   sc  the status code
304      *
305      * @see #sendError
306      */
307 
308     public void setStatus(int sc);
309   
310     /**
311      * @deprecated As of version 2.1, due to ambiguous meaning of the 
312      * message parameter. To set a status code 
313      * use <code>setStatus(int)</code>, to send an error with a description
314      * use <code>sendError(int, String)</code>.
315      *
316      * Sets the status code and message for this response.
317      * 
318      * @param   sc  the status code
319      * @param   sm  the status message
320      */
321 
322     public void setStatus(int sc, String   sm);
323 
324     
325     /*
326      * Server status codes; see RFC 2068.
327      */
328 
329     /**
330      * Status code (100) indicating the client can continue.
331      */
332 
333     public static final int SC_CONTINUE = 100;
334 
335     
336     /**
337      * Status code (101) indicating the server is switching protocols
338      * according to Upgrade header.
339      */
340 
341     public static final int SC_SWITCHING_PROTOCOLS = 101;
342 
343     /**
344      * Status code (200) indicating the request succeeded normally.
345      */
346 
347     public static final int SC_OK = 200;
348 
349     /**
350      * Status code (201) indicating the request succeeded and created
351      * a new resource on the server.
352      */
353 
354     public static final int SC_CREATED = 201;
355 
356     /**
357      * Status code (202) indicating that a request was accepted for
358      * processing, but was not completed.
359      */
360 
361     public static final int SC_ACCEPTED = 202;
362 
363     /**
364      * Status code (203) indicating that the meta information presented
365      * by the client did not originate from the server.
366      */
367 
368     public static final int SC_NON_AUTHORITATIVE_INFORMATION = 203;
369 
370     /**
371      * Status code (204) indicating that the request succeeded but that
372      * there was no new information to return.
373      */
374 
375     public static final int SC_NO_CONTENT = 204;
376 
377     /**
378      * Status code (205) indicating that the agent <em>SHOULD</em> reset
379      * the document view which caused the request to be sent.
380      */
381 
382     public static final int SC_RESET_CONTENT = 205;
383 
384     /**
385      * Status code (206) indicating that the server has fulfilled
386      * the partial GET request for the resource.
387      */
388 
389     public static final int SC_PARTIAL_CONTENT = 206;
390 
391     /**
392      * Status code (300) indicating that the requested resource
393      * corresponds to any one of a set of representations, each with
394      * its own specific location.
395      */
396 
397     public static final int SC_MULTIPLE_CHOICES = 300;
398 
399     /**
400      * Status code (301) indicating that the resource has permanently
401      * moved to a new location, and that future references should use a
402      * new URI with their requests.
403      */
404 
405     public static final int SC_MOVED_PERMANENTLY = 301;
406 
407     /**
408      * Status code (302) indicating that the resource has temporarily
409      * moved to another location, but that future references should
410      * still use the original URI to access the resource.
411      *
412      * This definition is being retained for backwards compatibility.
413      * SC_FOUND is now the preferred definition.
414      */
415 
416     public static final int SC_MOVED_TEMPORARILY = 302;
417 
418     /**
419     * Status code (302) indicating that the resource reside
420     * temporarily under a different URI. Since the redirection might
421     * be altered on occasion, the client should continue to use the
422     * Request-URI for future requests.(HTTP/1.1) To represent the
423     * status code (302), it is recommended to use this variable.
424     */
425 
426     public static final int SC_FOUND = 302;
427 
428     /**
429      * Status code (303) indicating that the response to the request
430      * can be found under a different URI.
431      */
432 
433     public static final int SC_SEE_OTHER = 303;
434 
435     /**
436      * Status code (304) indicating that a conditional GET operation
437      * found that the resource was available and not modified.
438      */
439 
440     public static final int SC_NOT_MODIFIED = 304;
441 
442     /**
443      * Status code (305) indicating that the requested resource
444      * <em>MUST</em> be accessed through the proxy given by the
445      * <code><em>Location</em></code> field.
446      */
447 
448     public static final int SC_USE_PROXY = 305;
449 
450      /**
451      * Status code (307) indicating that the requested resource 
452      * resides temporarily under a different URI. The temporary URI
453      * <em>SHOULD</em> be given by the <code><em>Location</em></code> 
454      * field in the response.
455      */
456 
457      public static final int SC_TEMPORARY_REDIRECT = 307;
458 
459     /**
460      * Status code (400) indicating the request sent by the client was
461      * syntactically incorrect.
462      */
463 
464     public static final int SC_BAD_REQUEST = 400;
465 
466     /**
467      * Status code (401) indicating that the request requires HTTP
468      * authentication.
469      */
470 
471     public static final int SC_UNAUTHORIZED = 401;
472 
473     /**
474      * Status code (402) reserved for future use.
475      */
476 
477     public static final int SC_PAYMENT_REQUIRED = 402;
478 
479     /**
480      * Status code (403) indicating the server understood the request
481      * but refused to fulfill it.
482      */
483 
484     public static final int SC_FORBIDDEN = 403;
485 
486     /**
487      * Status code (404) indicating that the requested resource is not
488      * available.
489      */
490 
491     public static final int SC_NOT_FOUND = 404;
492 
493     /**
494      * Status code (405) indicating that the method specified in the
495      * <code><em>Request-Line</em></code> is not allowed for the resource
496      * identified by the <code><em>Request-URI</em></code>.
497      */
498 
499     public static final int SC_METHOD_NOT_ALLOWED = 405;
500 
501     /**
502      * Status code (406) indicating that the resource identified by the
503      * request is only capable of generating response entities which have
504      * content characteristics not acceptable according to the accept
505      * headers sent in the request.
506      */
507 
508     public static final int SC_NOT_ACCEPTABLE = 406;
509 
510     /**
511      * Status code (407) indicating that the client <em>MUST</em> first
512      * authenticate itself with the proxy.
513      */
514 
515     public static final int SC_PROXY_AUTHENTICATION_REQUIRED = 407;
516 
517     /**
518      * Status code (408) indicating that the client did not produce a
519      * request within the time that the server was prepared to wait.
520      */
521 
522     public static final int SC_REQUEST_TIMEOUT = 408;
523 
524     /**
525      * Status code (409) indicating that the request could not be
526      * completed due to a conflict with the current state of the
527      * resource.
528      */
529 
530     public static final int SC_CONFLICT = 409;
531 
532     /**
533      * Status code (410) indicating that the resource is no longer
534      * available at the server and no forwarding address is known.
535      * This condition <em>SHOULD</em> be considered permanent.
536      */
537 
538     public static final int SC_GONE = 410;
539 
540     /**
541      * Status code (411) indicating that the request cannot be handled
542      * without a defined <code><em>Content-Length</em></code>.
543      */
544 
545     public static final int SC_LENGTH_REQUIRED = 411;
546 
547     /**
548      * Status code (412) indicating that the precondition given in one
549      * or more of the request-header fields evaluated to false when it
550      * was tested on the server.
551      */
552 
553     public static final int SC_PRECONDITION_FAILED = 412;
554 
555     /**
556      * Status code (413) indicating that the server is refusing to process
557      * the request because the request entity is larger than the server is
558      * willing or able to process.
559      */
560 
561     public static final int SC_REQUEST_ENTITY_TOO_LARGE = 413;
562 
563     /**
564      * Status code (414) indicating that the server is refusing to service
565      * the request because the <code><em>Request-URI</em></code> is longer
566      * than the server is willing to interpret.
567      */
568 
569     public static final int SC_REQUEST_URI_TOO_LONG = 414;
570 
571     /**
572      * Status code (415) indicating that the server is refusing to service
573      * the request because the entity of the request is in a format not
574      * supported by the requested resource for the requested method.
575      */
576 
577     public static final int SC_UNSUPPORTED_MEDIA_TYPE = 415;
578 
579     /**
580      * Status code (416) indicating that the server cannot serve the
581      * requested byte range.
582      */
583 
584     public static final int SC_REQUESTED_RANGE_NOT_SATISFIABLE = 416;
585 
586     /**
587      * Status code (417) indicating that the server could not meet the
588      * expectation given in the Expect request header.
589      */
590 
591     public static final int SC_EXPECTATION_FAILED = 417;
592 
593     /**
594      * Status code (500) indicating an error inside the HTTP server
595      * which prevented it from fulfilling the request.
596      */
597 
598     public static final int SC_INTERNAL_SERVER_ERROR = 500;
599 
600     /**
601      * Status code (501) indicating the HTTP server does not support
602      * the functionality needed to fulfill the request.
603      */
604 
605     public static final int SC_NOT_IMPLEMENTED = 501;
606 
607     /**
608      * Status code (502) indicating that the HTTP server received an
609      * invalid response from a server it consulted when acting as a
610      * proxy or gateway.
611      */
612 
613     public static final int SC_BAD_GATEWAY = 502;
614 
615     /**
616      * Status code (503) indicating that the HTTP server is
617      * temporarily overloaded, and unable to handle the request.
618      */
619 
620     public static final int SC_SERVICE_UNAVAILABLE = 503;
621 
622     /**
623      * Status code (504) indicating that the server did not receive
624      * a timely response from the upstream server while acting as
625      * a gateway or proxy.
626      */
627 
628     public static final int SC_GATEWAY_TIMEOUT = 504;
629 
630     /**
631      * Status code (505) indicating that the server does not support
632      * or refuses to support the HTTP protocol version that was used
633      * in the request message.
634      */
635 
636     public static final int SC_HTTP_VERSION_NOT_SUPPORTED = 505;
637 }
638
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