/*
    * Copyright 2009 Red Hat, Inc.
    *
    * Red Hat licenses this file to you under the Apache License, version 2.0
    * (the "License"); you may not use this file except in compliance with the
    * License.  You may obtain a copy of the License at:
    *
    *    http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package org.jboss.netty.handler.codec.http;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * The request method of HTTP or its derived protocols, such as
   * <a href="http://en.wikipedia.org/wiki/Real_Time_Streaming_Protocol">RTSP</a> and
   * <a href="http://en.wikipedia.org/wiki/Internet_Content_Adaptation_Protocol">ICAP</a>.
   *
   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
   * @author Andy Taylor (andy.taylor@jboss.org)
   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
   *
   * @apiviz.exclude
   */
  public class HttpMethod implements Comparable<HttpMethod> {
      /**
       * The OPTIONS method represents a request for information about the communication options available on the request/response
       * chain identified by the Request-URI. This method allows the client to determine the options and/or requirements
       * associated with a resource, or the capabilities of a server, without implying a resource action or initiating a
       * resource retrieval.
       */
      public static final HttpMethod OPTIONS = new HttpMethod("OPTIONS");
  
      /**
       * The GET method means retrieve whatever information (in the form of an entity) is identified by the Request-URI.
       * If the Request-URI refers to a data-producing process, it is the produced data which shall be returned as the entity
       * in the response and not the source text of the process, unless that text happens to be the output of the process.
       */
      public static final HttpMethod GET = new HttpMethod("GET");
  
      /**
       * The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response.
       */
      public static final HttpMethod HEAD = new HttpMethod("HEAD");
  
      /**
       * The POST method is used to request that the origin server accept the entity enclosed in the request as a new
       * subordinate of the resource identified by the Request-URI in the Request-Line.
       */
      public static final HttpMethod POST = new HttpMethod("POST");
  
      /**
       * The PUT method requests that the enclosed entity be stored under the supplied Request-URI.
       */
      public static final HttpMethod PUT = new HttpMethod("PUT");
  
      /**
       * The PATCH method requests that a set of changes described in the
       * request entity be applied to the resource identified by the Request-URI.
       */
      public static final HttpMethod PATCH = new HttpMethod("PATCH");
  
      /**
       * The DELETE method requests that the origin server delete the resource identified by the Request-URI.
       */
      public static final HttpMethod DELETE = new HttpMethod("DELETE");
  
      /**
       * The TRACE method is used to invoke a remote, application-layer loop- back of the request message.
       */
      public static final HttpMethod TRACE = new HttpMethod("TRACE");
  
      /**
       * This specification reserves the method name CONNECT for use with a proxy that can dynamically switch to being a tunnel
       */
      public static final HttpMethod CONNECT = new HttpMethod("CONNECT");
  
      private static final Map<String, HttpMethod> methodMap =
              new HashMap<String, HttpMethod>();
  
      static {
          methodMap.put(OPTIONS.toString(), OPTIONS);
          methodMap.put(GET.toString(), GET);
          methodMap.put(HEAD.toString(), HEAD);
          methodMap.put(POST.toString(), POST);
          methodMap.put(PUT.toString(), PUT);
          methodMap.put(PATCH.toString(), PATCH);
          methodMap.put(DELETE.toString(), DELETE);
          methodMap.put(TRACE.toString(), TRACE);
          methodMap.put(CONNECT.toString(), CONNECT);
      }
  
     /**
      * Returns the {@link HttpMethod} represented by the specified name.
      * If the specified name is a standard HTTP method name, a cached instance
      * will be returned.  Otherwise, a new instance will be returned.
      */
     public static HttpMethod valueOf(String name) {
         if (name == null) {
             throw new NullPointerException("name");
         }
 
         name = name.trim().toUpperCase();
         if (name.length() == 0) {
             throw new IllegalArgumentException("empty name");
         }
 
         HttpMethod result = methodMap.get(name);
         if (result != null) {
             return result;
         } else {
             return new HttpMethod(name);
         }
     }
 
     private final String name;
 
     /**
      * Creates a new HTTP method with the specified name.  You will not need to
      * create a new method unless you are implementing a protocol derived from
      * HTTP, such as
      * <a href="http://en.wikipedia.org/wiki/Real_Time_Streaming_Protocol">RTSP</a> and
      * <a href="http://en.wikipedia.org/wiki/Internet_Content_Adaptation_Protocol">ICAP</a>
      */
     public HttpMethod(String name) {
         if (name == null) {
             throw new NullPointerException("name");
         }
 
         name = name.trim().toUpperCase();
         if (name.length() == 0) {
             throw new IllegalArgumentException("empty name");
         }
 
         for (int i = 0; i < name.length(); i ++) {
             if (Character.isISOControl(name.charAt(i)) ||
                 Character.isWhitespace(name.charAt(i))) {
                 throw new IllegalArgumentException("invalid character in name");
             }
         }
 
         this.name = name;
     }
 
     /**
      * Returns the name of this method.
      */
     public String getName() {
         return name;
     }
 
     @Override
     public int hashCode() {
         return getName().hashCode();
     }
 
     @Override
     public boolean equals(Object o) {
         if (!(o instanceof HttpMethod)) {
             return false;
         }
 
         HttpMethod that = (HttpMethod) o;
         return getName().equals(that.getName());
     }
 
     @Override
     public String toString() {
         return getName();
     }
 
     public int compareTo(HttpMethod o) {
         return getName().compareTo(o.getName());
     }
 }