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1   /*
2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/java/org/apache/commons/httpclient/HeaderGroup.java $
3    * $Revision: 1425331 $
4    * $Date: 2012-12-22 19:29:41 +0100 (Sat, 22 Dec 2012) $
5    *
6    * ====================================================================
7    *
8    *  Licensed to the Apache Software Foundation (ASF) under one or more
9    *  contributor license agreements.  See the NOTICE file distributed with
10   *  this work for additional information regarding copyright ownership.
11   *  The ASF licenses this file to You under the Apache License, Version 2.0
12   *  (the "License"); you may not use this file except in compliance with
13   *  the License.  You may obtain a copy of the License at
14   *
15   *      http://www.apache.org/licenses/LICENSE-2.0
16   *
17   *  Unless required by applicable law or agreed to in writing, software
18   *  distributed under the License is distributed on an "AS IS" BASIS,
19   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   *  See the License for the specific language governing permissions and
21   *  limitations under the License.
22   * ====================================================================
23   *
24   * This software consists of voluntary contributions made by many
25   * individuals on behalf of the Apache Software Foundation.  For more
26   * information on the Apache Software Foundation, please see
27   * <http://www.apache.org/>.
28   *
29   */
30  
31  package org.apache.commons.httpclient;
32  
33  import java.util.ArrayList;
34  import java.util.Iterator;
35  import java.util.List;
36  
37  /***
38   * A class for combining a set of headers.  This class allows for multiple
39   * headers with the same name and keeps track of the order in which headers were
40   * added.
41   * 
42   * @author Michael Becke
43   * 
44   * @since 2.0beta1
45   */
46  public class HeaderGroup {
47  
48      /*** The list of headers for this group, in the order in which they were added */
49      private List headers;
50  
51      /***
52       * Constructor for HeaderGroup.
53       */
54      public HeaderGroup() {
55          this.headers = new ArrayList();
56      }
57      
58      /***
59       * Removes any contained headers.
60       */
61      public void clear() {
62          headers.clear();
63      }
64      
65      /***
66       * Adds the given header to the group.  The order in which this header was
67       * added is preserved.
68       * 
69       * @param header the header to add
70       */
71      public void addHeader(Header header) {
72          headers.add(header);
73      }
74      
75      /***
76       * Removes the given header.
77       *
78       * @param header the header to remove
79       */
80      public void removeHeader(Header header) {
81          headers.remove(header);
82      }
83  
84      /***
85       * Sets all of the headers contained within this group overriding any
86       * existing headers. The headers are added in the order in which they appear
87       * in the array.
88       * 
89       * @param headers the headers to set
90       */
91      public void setHeaders(Header[] headers) {
92          clear();
93          
94          for (int i = 0; i < headers.length; i++) {
95              addHeader(headers[i]);
96          }
97      }
98      
99      /***
100      * Gets a header representing all of the header values with the given name.
101      * If more that one header with the given name exists the values will be
102      * combined with a "," as per RFC 2616.
103      * 
104      * <p>Header name comparison is case insensitive.
105      * 
106      * @param name the name of the header(s) to get
107      * @return a header with a condensed value or <code>null</code> if no
108      * headers by the given name are present
109      */
110     public Header getCondensedHeader(String name) {
111         Header[] headers = getHeaders(name);
112         
113         if (headers.length == 0) {
114             return null;   
115         } else if (headers.length == 1) {
116             return new Header(headers[0].getName(), headers[0].getValue());
117         } else {
118             StringBuffer valueBuffer = new StringBuffer(headers[0].getValue());
119             
120             for (int i = 1; i < headers.length; i++) {
121                 valueBuffer.append(", ");
122                 valueBuffer.append(headers[i].getValue());
123             }
124             
125             return new Header(name.toLowerCase(), valueBuffer.toString());
126         }
127     }
128     
129     /***
130      * Gets all of the headers with the given name.  The returned array
131      * maintains the relative order in which the headers were added.  
132      * 
133      * <p>Header name comparison is case insensitive.
134      * 
135      * @param name the name of the header(s) to get
136      * 
137      * @return an array of length >= 0
138      */
139     public Header[] getHeaders(String name) {
140         ArrayList headersFound = new ArrayList();
141         
142         for (Iterator headerIter = headers.iterator(); headerIter.hasNext();) {
143             Header header = (Header) headerIter.next();
144             if (header.getName().equalsIgnoreCase(name)) {
145                 headersFound.add(header);
146             }
147         }
148         
149         return (Header[]) headersFound.toArray(new Header[headersFound.size()]);
150     }
151     
152     /***
153      * Gets the first header with the given name.
154      * 
155      * <p>Header name comparison is case insensitive.
156      * 
157      * @param name the name of the header to get
158      * @return the first header or <code>null</code>
159      */
160     public Header getFirstHeader(String name) {
161         for (Iterator headerIter = headers.iterator(); headerIter.hasNext();) {
162             Header header = (Header) headerIter.next();
163             if (header.getName().equalsIgnoreCase(name)) {
164                 return header;
165             }
166         }
167         
168         return null;                
169     }
170     
171     /***
172      * Gets the last header with the given name.
173      *
174      * <p>Header name comparison is case insensitive.
175      *
176      * @param name the name of the header to get
177      * @return the last header or <code>null</code>
178      */
179     public Header getLastHeader(String name) {
180         // start at the end of the list and work backwards
181         for (int i = headers.size() - 1; i >= 0; i--) {
182             Header header = (Header) headers.get(i);
183             if (header.getName().equalsIgnoreCase(name)) {
184                 return header;
185             }            
186         }
187         
188         return null;        
189     }
190     
191     /***
192      * Gets all of the headers contained within this group.
193      * 
194      * @return an array of length >= 0
195      */
196     public Header[] getAllHeaders() {
197         return (Header[]) headers.toArray(new Header[headers.size()]);
198     }
199     
200     /***
201      * Tests if headers with the given name are contained within this group.
202      * 
203      * <p>Header name comparison is case insensitive.
204      * 
205      * @param name the header name to test for
206      * @return <code>true</code> if at least one header with the name is
207      * contained, <code>false</code> otherwise
208      */
209     public boolean containsHeader(String name) {
210         for (Iterator headerIter = headers.iterator(); headerIter.hasNext();) {
211             Header header = (Header) headerIter.next();
212             if (header.getName().equalsIgnoreCase(name)) {
213                 return true;
214             }
215         }
216         
217         return false;
218     }
219 
220     /***
221      * Returns an iterator over this group of headers.
222      * 
223      * @return iterator over this group of headers.
224      * 
225      * @since 3.0
226      */
227     public Iterator getIterator() {
228         return this.headers.iterator(); 
229     }
230 }