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 w800'>
021 *    Accept-Ranges: bytes
022 * </p>
023 *
024 * <ul class='seealso'>
025 *    <li class='extlink'>{@doc RFC2616}
026 * </ul>
027 *
028 * @param <E> The enum type.
029 */
030public class HeaderEnum<E extends Enum<E>> {
031
032   private final String value;
033   private final E enumValue;
034
035   /**
036    * Constructor.
037    *
038    * @param value The raw header value.
039    * @param enumClass The enum class.
040    * @param def The default enum value if the value could not be parsed.
041    */
042   protected HeaderEnum(String value, Class<E> enumClass, E def) {
043      this.value = value;
044      E _enumValue = def;
045      try {
046         _enumValue = Enum.valueOf(enumClass, value.toUpperCase());
047      } catch (Exception e) {
048         _enumValue = def;
049      }
050      this.enumValue = _enumValue;
051   }
052
053   /**
054    * Returns <jk>true</jk> if the specified value is the same using {@link String#equalsIgnoreCase(String)}.
055    *
056    * @return <jk>true</jk> if the specified value is the same.
057    */
058   public E asEnum() {
059      return enumValue;
060   }
061
062   /**
063    * Returns this header as a simple string value.
064    *
065    * <p>
066    * Functionally equivalent to calling {@link #toString()}.
067    *
068    * @return This header as a simple string.
069    */
070   public String asString() {
071      return value;
072   }
073
074   @Override /* Object */
075   public String toString() {
076      return value == null ? "" : value;
077   }
078}