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      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/client/methods/HttpOptions.java $
      3  * $Revision: 664505 $
      4  * $Date: 2008-06-08 06:21:20 -0700 (Sun, 08 Jun 2008) $
      5  *
      6  * ====================================================================
      7  * Licensed to the Apache Software Foundation (ASF) under one
      8  * or more contributor license agreements.  See the NOTICE file
      9  * distributed with this work for additional information
     10  * regarding copyright ownership.  The ASF licenses this file
     11  * to you under the Apache License, Version 2.0 (the
     12  * "License"); you may not use this file except in compliance
     13  * with 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,
     18  * software distributed under the License is distributed on an
     19  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     20  * KIND, either express or implied.  See the License for the
     21  * specific language governing permissions and limitations
     22  * under the License.
     23  * ====================================================================
     24  *
     25  * This software consists of voluntary contributions made by many
     26  * individuals on behalf of the Apache Software Foundation.  For more
     27  * information on the Apache Software Foundation, please see
     28  * <http://www.apache.org/>.
     29  *
     30  */
     31 
     32 package org.apache.http.client.methods;
     33 
     34 import java.net.URI;
     35 import java.util.HashSet;
     36 import java.util.Set;
     37 
     38 import org.apache.http.Header;
     39 import org.apache.http.HeaderElement;
     40 import org.apache.http.HeaderIterator;
     41 import org.apache.http.HttpResponse;
     42 
     43 /**
     44  * HTTP OPTIONS method.
     45  * <p>
     46  * The HTTP OPTIONS method is defined in section 9.2 of
     47  * <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC2616</a>:
     48  * <blockquote>
     49  *  The OPTIONS method represents a request for information about the
     50  *  communication options available on the request/response chain
     51  *  identified by the Request-URI. This method allows the client to
     52  *  determine the options and/or requirements associated with a resource,
     53  *  or the capabilities of a server, without implying a resource action
     54  *  or initiating a resource retrieval.
     55  * </blockquote>
     56  * </p>
     57  *
     58  * @version $Revision: 664505 $
     59  *
     60  * @since 4.0
     61  */
     62 public class HttpOptions extends HttpRequestBase {
     63 
     64     public final static String METHOD_NAME = "OPTIONS";
     65 
     66     public HttpOptions() {
     67         super();
     68     }
     69 
     70     public HttpOptions(final URI uri) {
     71         super();
     72         setURI(uri);
     73     }
     74 
     75     /**
     76      * @throws IllegalArgumentException if the uri is invalid.
     77      */
     78     public HttpOptions(final String uri) {
     79         super();
     80         setURI(URI.create(uri));
     81     }
     82 
     83     @Override
     84     public String getMethod() {
     85         return METHOD_NAME;
     86     }
     87 
     88     public Set<String> getAllowedMethods(final HttpResponse response) {
     89         if (response == null) {
     90             throw new IllegalArgumentException("HTTP response may not be null");
     91         }
     92 
     93         HeaderIterator it = response.headerIterator("Allow");
     94         Set<String> methods = new HashSet<String>();
     95         while (it.hasNext()) {
     96             Header header = it.nextHeader();
     97             HeaderElement[] elements = header.getElements();
     98             for (HeaderElement element : elements) {
     99                 methods.add(element.getName());
    100             }
    101         }
    102         return methods;
    103     }
    104 
    105 }
    106