java/src/main/com/google/appengine/api/datastore/Link.java

   1 /*
   2  * Copyright 2008 Google Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
   5  * use this file except in compliance with the License. You may obtain a copy of
   6  * the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  13  * License for the specific language governing permissions and limitations under
  14  * the License.
  15  */
  16 package com.google.appengine.api.datastore;
  17
  18 import java.io.Serializable;
  19
  20 /**
  21  * A {@code Link} is a URL of limited length.
  22  *
  23  * In addition to adding the meaning of {@code URL} onto a String, a {@code Link}
  24  * can also be longer than a Text value, with a limit of 2083 characters.
  25  *
  26  */
  27 public final class Link implements Serializable, Comparable<Link> {
  28
  29   public static final long serialVersionUID = 731239796613544443L;
  30
  31   private String value;
  32
  33   /**
  34    * This constructor exists for frameworks (e.g. Google Web Toolkit)
  35    * that require it for serialization purposes.  It should not be
  36    * called explicitly.
  37    */
  38   @SuppressWarnings("unused")
  39   private Link() {
  40     value = null;
  41   }
  42
  43   /**
  44    * Constructs a new {@code Link} object with the specified value.
  45    * This object cannot be modified after construction.
  46    */
  47   public Link(String value) {
  48     this.value = value;
  49   }
  50
  51   /**
  52    * Returns the value of this {@code Link}.
  53    */
  54   public String getValue() {
  55     return value;
  56   }
  57
  58   @Override
  59   public int hashCode() {
  60     return value.hashCode();
  61   }
  62
  63   /**
  64    * Two {@code Link} objects are considered equal if their content
  65    * strings match exactly.
  66    */
  67   @Override
  68   public boolean equals(Object object) {
  69     if (object instanceof Link) {
  70       Link key = (Link) object;
  71       return value.equals(key.value);
  72     }
  73     return false;
  74   }
  75
  76   /**
  77    * Returns the entire text of this {@code Link}.
  78    */
  79   @Override
  80   public String toString() {
  81     return value;
  82   }
  83
  84   @Override
  85   public int compareTo(Link l) {
  86     return value.compareTo(l.value);
  87   }
  88 }