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

   1 // Copyright 2007 Google Inc. All rights reserved.
   2
   3 package com.google.appengine.api.datastore;
   4
   5 import java.io.Serializable;
   6 import java.util.Arrays;
   7
   8 /**
   9  * {@code ShortBlob} contains an array of bytes no longer than
  10  * {@link DataTypeUtils#MAX_SHORT_BLOB_PROPERTY_LENGTH}.  Unlike {@link Blob},
  11  * {@code ShortBlobs} are indexed by the datastore and can therefore be
  12  * filtered and sorted on in queries.  If your data is too large to fit
  13  * in a {@code ShortBlob} use {@link Blob} instead.
  14  *
  15  */
  16 public final class ShortBlob implements Serializable, Comparable<ShortBlob> {
  17
  18   public static final long serialVersionUID = -3427166602866836472L;
  19
  20   private byte[] bytes;
  21
  22   /**
  23    * This constructor exists for frameworks (e.g. Google Web Toolkit)
  24    * that require it for serialization purposes.  It should not be
  25    * called explicitly.
  26    */
  27   @SuppressWarnings("unused")
  28   private ShortBlob() {
  29     bytes = null;
  30   }
  31
  32   /**
  33    * Construct a new {@code ShortBlob} with the specified bytes.  This
  34    * blob cannot be modified after construction.
  35    */
  36   public ShortBlob(byte[] bytes) {
  37
  38     this.bytes = new byte[bytes.length];
  39     System.arraycopy(bytes, 0, this.bytes, 0, bytes.length);
  40   }
  41
  42   /**
  43    * Return the bytes stored in this {@code ShortBlob}.
  44    */
  45   public byte[] getBytes() {
  46     return bytes;
  47   }
  48
  49   @Override
  50   public int hashCode() {
  51     return Arrays.hashCode(bytes);
  52   }
  53
  54   /**
  55    * Two {@code ShortBlob} objects are considered equal if their contained
  56    * bytes match exactly.
  57    */
  58   @Override
  59   public boolean equals(Object object) {
  60     if (object instanceof ShortBlob) {
  61       ShortBlob other = (ShortBlob) object;
  62       return Arrays.equals(bytes, other.bytes);
  63     }
  64     return false;
  65   }
  66
  67   /**
  68    * Simply prints the number of bytes contained in this {@code ShortBlob}.
  69    */
  70   @Override
  71   public String toString() {
  72     return "<ShortBlob: " + bytes.length + " bytes>";
  73   }
  74
  75   @Override
  76   public int compareTo(ShortBlob other) {
  77     DataTypeTranslator.ComparableByteArray cba1 = new DataTypeTranslator.ComparableByteArray(bytes);
  78     DataTypeTranslator.ComparableByteArray cba2 =
  79         new DataTypeTranslator.ComparableByteArray(other.bytes);
  80     return cba1.compareTo(cba2);
  81   }
  82 }