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.header;
014
015import static org.apache.juneau.common.internal.ArgUtils.*;
016import static org.apache.juneau.common.internal.StringUtils.*;
017import static org.apache.juneau.internal.ObjectUtils.*;
018
019/**
020 * Represents a validator value.
021 *
022 * <p>
023 * <h5 class='figure'>Example</h5>
024 * <p class='bcode'>
025 *    ETag: "123456789"    – A strong ETag validator
026 *    ETag: W/"123456789"  – A weak ETag validator
027 * </p>
028 *
029 * <h5 class='section'>See Also:</h5><ul>
030 *    <li class='link'><a class="doclink" href="../../../../../index.html#juneau-rest-common">juneau-rest-common</a>
031 *    <li class='extlink'><a class="doclink" href="https://www.w3.org/Protocols/rfc2616/rfc2616.html">Hypertext Transfer Protocol -- HTTP/1.1</a>
032 * </ul>
033 */
034public class EntityTag {
035
036   //-----------------------------------------------------------------------------------------------------------------
037   // Static
038   //-----------------------------------------------------------------------------------------------------------------
039
040   private final String value;
041   private final boolean isWeak, isAny;
042
043   /**
044    * Static creator.
045    *
046    * @param value The validator string value.
047    * @return A new header bean or <jk>null</jk> if the value was <jk>null</jk>.
048    * @throws IllegalArgumentException If attempting to set an invalid entity tag value.
049    */
050   public static EntityTag of(Object value) {
051      Object o = unwrap(value);
052      return o == null ? null : new EntityTag(o.toString());
053   }
054
055   //-----------------------------------------------------------------------------------------------------------------
056   // Instance
057   //-----------------------------------------------------------------------------------------------------------------
058
059   /**
060    * Constructor.
061    *
062    * @param value The validator string value.
063    * @throws IllegalArgumentException If attempting to set an invalid entity tag value.
064    */
065   public EntityTag(String value) {
066      assertArgNotNull("value", value);
067
068      value = trim(emptyIfNull(value));
069      isWeak = value.startsWith("W/");
070      isAny = "*".equals(value);
071
072      if (! isAny) {
073         if (isWeak)
074            value = value.substring(2);
075         if (value.length() > 1 && value.charAt(0) == '"' && value.charAt(value.length()-1) == '"')
076            value = value.substring(1, value.length()-1);
077         else
078            throw new IllegalArgumentException("Invalid value for entity-tag: ["+(isWeak ? ("W/"+value) : value)+"]");
079      }
080      this.value = value;
081
082   }
083
084   /**
085    * Returns the validator value stripped of quotes and weak tag.
086    *
087    * @return The validator value.
088    */
089   public String getEntityValue() {
090      return value;
091   }
092
093   /**
094    * Returns <jk>true</jk> if the weak flag is present in the value.
095    *
096    * @return <jk>true</jk> if the weak flag is present in the value.
097    */
098   public boolean isWeak() {
099      return isWeak;
100   }
101
102   /**
103    * Returns <jk>true</jk> if the validator string value is <c>*</c>.
104    *
105    * @return <jk>true</jk> if the validator string value is <c>*</c>.
106    */
107   public boolean isAny() {
108      return isAny;
109   }
110
111   @Override
112   public String toString() {
113      return (isWeak ? "W/" : "") + (isAny() ? "*" : ('"' + value + '"'));
114   }
115}