001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.http;
014
015/**
016 * Category of headers that consist of a single enum value.
017 * 
018 * <p>
019 * <h5 class='figure'>Example</h5>
020 * <p class='bcode'>
021 *    Accept-Ranges: bytes
022 * </p>
023 * 
024 * <h5 class='section'>See Also:</h5>
025 * <ul class='doctree'>
026 *    <li class='extlink'><a class='doclink' href='https://www.w3.org/Protocols/rfc2616/rfc2616.html'>Hypertext Transfer Protocol -- HTTP/1.1</a>
027 * </ul>
028 * 
029 * @param <E> The enum type.
030 */
031public class HeaderEnum<E extends Enum<E>> {
032
033   private final String value;
034   private final E enumValue;
035
036   /**
037    * Constructor.
038    * 
039    * @param value The raw header value.
040    * @param enumClass The enum class.
041    * @param def The default enum value if the value could not be parsed.
042    */
043   protected HeaderEnum(String value, Class<E> enumClass, E def) {
044      this.value = value;
045      E _enumValue = def;
046      try {
047         _enumValue = Enum.valueOf(enumClass, value.toUpperCase());
048      } catch (Exception e) {
049         _enumValue = def;
050      }
051      this.enumValue = _enumValue;
052   }
053
054   /**
055    * Returns <jk>true</jk> if the specified value is the same using {@link String#equalsIgnoreCase(String)}.
056    * 
057    * @return <jk>true</jk> if the specified value is the same.
058    */
059   public E asEnum() {
060      return enumValue;
061   }
062
063   /**
064    * Returns this header as a simple string value.
065    * 
066    * <p>
067    * Functionally equivalent to calling {@link #toString()}.
068    * 
069    * @return This header as a simple string.
070    */
071   public String asString() {
072      return value;
073   }
074
075   @Override /* Object */
076   public String toString() {
077      return value == null ? "" : value;
078   }
079}