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

   1 /*
   2  * Copyright 2007 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  * {@code Text} wraps around a string of unlimited size.
  22  *
  23  * Ordinary Java strings stored as properties in {@code Entity}
  24  * objects are limited to 500 characters.  However, {@code Text}
  25  * objects can also be stored in properties, and are unlimited in
  26  * size.  However, they will not be indexed for query purposes.
  27  *
  28  */
  29 public final class Text implements Serializable {
  30
  31   public static final long serialVersionUID = -8389037235415462280L;
  32
  33   private String value;
  34
  35   /**
  36    * This constructor exists for frameworks (e.g. Google Web Toolkit)
  37    * that require it for serialization purposes.  It should not be
  38    * called explicitly.
  39    */
  40   @SuppressWarnings("unused")
  41   private Text() {
  42   }
  43
  44   /**
  45    * Construct a new {@code Text} object with the specified value.
  46    * This object cannot be modified after construction.
  47    */
  48   public Text(String value) {
  49     this.value = value;
  50   }
  51
  52   /**
  53    * Return the value of this {@code Text}.  Can be {@code null}.
  54    */
  55   public String getValue() {
  56     return value;
  57   }
  58
  59   @Override
  60   public int hashCode() {
  61     if (value == null) {
  62       return -1;
  63     }
  64     return value.hashCode();
  65   }
  66
  67   /**
  68    * Two {@code Text} objects are considered equal if their content
  69    * strings match exactly.
  70    */
  71   @Override
  72   public boolean equals(Object object) {
  73     if (object instanceof Text) {
  74       Text key = (Text) object;
  75       if (value == null) {
  76         return key.value == null;
  77       }
  78       return value.equals(key.value);
  79     }
  80     return false;
  81   }
  82
  83   /**
  84    * Returns the first 70 characters of the underlying string.
  85    */
  86   @Override
  87   public String toString() {
  88     if (value == null) {
  89       return "<Text: null>";
  90     }
  91     String text = value;
  92     if (text.length() > 70) {
  93       text = text.substring(0, 70) + "...";
  94     }
  95     return "<Text: " + text + ">";
  96   }
  97 }