/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.handler.codec.http;
  
  import io.netty.util.AsciiString;
  
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  
  /**
   * The request method of HTTP or its derived protocols, such as
   * <a href="https://en.wikipedia.org/wiki/Real_Time_Streaming_Protocol">RTSP</a> and
   * <a href="https://en.wikipedia.org/wiki/Internet_Content_Adaptation_Protocol">ICAP</a>.
   */
  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(AsciiString.cached("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(AsciiString.cached("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(AsciiString.cached("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(AsciiString.cached("POST"));
  
      /**
       * The PUT method requests that the enclosed entity be stored under the supplied Request-URI.
       */
      public static final HttpMethod PUT = new HttpMethod(AsciiString.cached("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(AsciiString.cached("PATCH"));
  
      /**
       * The DELETE method requests that the origin server delete the resource identified by the
       * Request-URI.
       */
      public static final HttpMethod DELETE = new HttpMethod(AsciiString.cached("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(AsciiString.cached("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(AsciiString.cached("CONNECT"));
  
      /**
       * The QUERY method requests that the request target process the enclosed content in a safe and
       * idempotent manner and then respond with the result of that processing.
       */
      public static final HttpMethod QUERY = new HttpMethod(AsciiString.cached("QUERY"));
  
      /**
       * 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.equals("GET")) {
             return HttpMethod.GET;
         } else if (name.equals("POST")) {
             return HttpMethod.POST;
         } else if (name.equals("PUT")) {
             return HttpMethod.PUT;
         } else if (name.equals("CONNECT")) {
             return HttpMethod.CONNECT;
         } else if (name.equals("OPTIONS")) {
             return HttpMethod.OPTIONS;
         } else if (name.equals("HEAD")) {
             return HttpMethod.HEAD;
         } else if (name.equals("PATCH")) {
             return HttpMethod.PATCH;
         } else if (name.equals("DELETE")) {
             return HttpMethod.DELETE;
         } else if (name.equals("TRACE")) {
             return HttpMethod.TRACE;
         } else if (name.equals("QUERY")) {
             return HttpMethod.QUERY;
         }
         return new HttpMethod(name);
     }
 
     private final AsciiString name;
 
     /**
      * Private constructor for the built-in constants defined in this class.
      * The names are compiler-controlled literals that are already valid HTTP tokens,
      * so there is no need to validate or trim them at runtime.
      */
     private HttpMethod(AsciiString name) {
         this.name = 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="https://en.wikipedia.org/wiki/Real_Time_Streaming_Protocol">RTSP</a> and
      * <a href="https://en.wikipedia.org/wiki/Internet_Content_Adaptation_Protocol">ICAP</a>
      */
     public HttpMethod(String name) {
         checkNotNull(name, "name");
         // The name must be non-empty and contain only valid HTTP token characters.
         if (name.isEmpty()) {
             throw new IllegalArgumentException("name cannot be empty");
         }
         int index = HttpHeaderValidationUtil.validateToken(name);
         if (index != -1) {
             throw new IllegalArgumentException(
                     "Illegal character in HTTP Method: 0x" + Integer.toHexString(name.charAt(index)));
         }
         this.name = AsciiString.cached(name);
     }
 
     /**
      * Returns the name of this method.
      */
     public String name() {
         return name.toString();
     }
 
     /**
      * Returns the name of this method.
      */
     public AsciiString asciiName() {
         return name;
     }
 
     @Override
     public int hashCode() {
         return name().hashCode();
     }
 
     @Override
     public boolean equals(Object o) {
         if (this == o) {
             return true;
         }
         if (!(o instanceof HttpMethod)) {
             return false;
         }
 
         HttpMethod that = (HttpMethod) o;
         return name().equals(that.name());
     }
 
     @Override
     public String toString() {
         return name.toString();
     }
 
     @Override
     public int compareTo(HttpMethod o) {
         if (o == this) {
             return 0;
         }
         return name().compareTo(o.name());
     }
 }