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

   1 // Copyright 2012 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.datastore;
   4
   5 import static com.google.common.base.Preconditions.checkArgument;
   6 import static com.google.common.base.Preconditions.checkNotNull;
   7
   8 import com.google.appengine.api.blobstore.BlobKey;
   9 import com.google.appengine.api.datastore.DataTypeTranslator.Type;
  10 import com.google.appengine.api.users.User;
  11 import com.google.apphosting.datastore.EntityV4;
  12 import com.google.storage.onestore.v3.OnestoreEntity.PropertyValue;
  13
  14 import java.io.IOException;
  15 import java.io.Serializable;
  16 import java.util.Arrays;
  17
  18 /**
  19  * A raw datastore value.
  20  *
  21  * These are returned by projection queries when a {@link PropertyProjection} does not
  22  * specify a type.
  23  *
  24  * @see Query#getProjections()
  25  */
  26 public final class RawValue implements Serializable {
  27   private static final long serialVersionUID = 8176992854378814427L;
  28   private transient PropertyValue valueV3 = null;
  29   private transient EntityV4.Value valueV4 = null;
  30
  31   RawValue(PropertyValue propertyValue) {
  32     this.valueV3 = checkNotNull(propertyValue);
  33   }
  34
  35   RawValue(EntityV4.Value propertyValue) {
  36     this.valueV4 = checkNotNull(propertyValue);
  37   }
  38
  39   /**
  40    * Returns an object of the exact type passed in.
  41    *
  42    * @param type the class object for the desired type
  43    * @return an object of type T or {@code null}
  44    * @throws IllegalArgumentException if the raw value cannot be converted into the given type
  45    */
  46   @SuppressWarnings("unchecked")
  47   public <T> T asStrictType(Class<T> type) {
  48     Object value = asType(type);
  49     if (value != null) {
  50       checkArgument(type.isAssignableFrom(value.getClass()), "Unsupported type: " + type);
  51     }
  52     return (T) value;
  53   }
  54
  55   /**
  56    * Returns the object normally returned by the datastore if given type is passed in.
  57    *
  58    * All integer values are returned as {@link Long}.
  59    * All floating point values are returned as {@link Double}.
  60    *
  61    * @param type the class object for the desired type
  62    * @return an object of type T or {@code null}
  63    * @throws IllegalArgumentException if the raw value cannot be converted into the given type
  64    */
  65   public Object asType(Class<?> type) {
  66     Type<?> typeAdapter = DataTypeTranslator.getTypeMap().get(type);
  67     checkArgument(typeAdapter != null, "Unsupported type: " + type);
  68
  69     if (valueV3 != null) {
  70       if (typeAdapter.hasValue(valueV3)) {
  71         return typeAdapter.getValue(valueV3);
  72       }
  73     } else if (valueV4 != null) {
  74       if (typeAdapter.hasValue(valueV4)) {
  75         return typeAdapter.getValue(valueV4);
  76       }
  77     }
  78
  79     checkArgument(getValue() == null, "Type mismatch.");
  80     return null;
  81   }
  82
  83   /**
  84    * Returns the raw value.
  85    *
  86    * @return An object of type {@link Boolean}, {@link Double}, {@link GeoPt}, {@link Key},
  87    * {@code byte[]}, {@link User} or {@code null}.
  88    */
  89   public Object getValue() {
  90     if (valueV3 != null) {
  91       if (valueV3.hasBooleanValue()) {
  92         return valueV3.isBooleanValue();
  93       } else if (valueV3.hasDoubleValue()) {
  94         return valueV3.getDoubleValue();
  95       } else if (valueV3.hasInt64Value()) {
  96         return valueV3.getInt64Value();
  97       } else if (valueV3.hasPointValue()) {
  98         return asType(GeoPt.class);
  99       } else if (valueV3.hasReferenceValue()) {
 100         return asType(Key.class);
 101       } else if (valueV3.hasStringValue()) {
 102         return valueV3.getStringValueAsBytes();
 103       } else if (valueV3.hasUserValue()) {
 104         return asType(User.class);
 105       }
 106     } else if (valueV4 != null) {
 107       if (valueV4.hasBooleanValue()) {
 108         return valueV4.getBooleanValue();
 109       } else if (valueV4.hasDoubleValue()) {
 110         return valueV4.getDoubleValue();
 111       } else if (valueV4.hasIntegerValue()) {
 112         return valueV4.getIntegerValue();
 113       } else if (valueV4.hasEntityValue()) {
 114         if (valueV4.getMeaning() == 20) {
 115           return asType(User.class);
 116         }
 117         return asType(GeoPt.class);
 118       } else if (valueV4.hasKeyValue()) {
 119         return asType(Key.class);
 120       } else if (valueV4.hasStringValue()) {
 121         return valueV4.getStringValueBytes().toByteArray();
 122       } else if (valueV4.hasBlobKeyValue()) {
 123         return asType(BlobKey.class);
 124       } else if (valueV4.hasBlobValue()) {
 125         return valueV4.getBlobValue().toByteArray();
 126       } else if (valueV4.hasTimestampMicrosecondsValue()) {
 127         return valueV4.getTimestampMicrosecondsValue();
 128       } else if (valueV4.hasGeoPointValue()) {
 129         return asType(GeoPt.class);
 130       }
 131     }
 132     return null;
 133   }
 134
 135   private void writeObject(java.io.ObjectOutputStream out) throws IOException {
 136     if (valueV3 != null) {
 137       out.write(1);
 138       valueV3.writeTo(out);
 139     } else {
 140       out.write(2);
 141       valueV4.writeTo(out);
 142     }
 143     out.defaultWriteObject();
 144   }
 145
 146   private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
 147     int version = in.read();
 148     if (version == 1) {
 149       valueV3 = new PropertyValue();
 150       valueV3.parseFrom(in);
 151     } else if (version == 2) {
 152       valueV4 = EntityV4.Value.PARSER.parseFrom(in);
 153     } else {
 154       checkArgument(false, "unknown RawValue format");
 155     }
 156     in.defaultReadObject();
 157   }
 158
 159   @Override
 160   public int hashCode() {
 161     Object value = getValue();
 162     return value == null ? 0 : value.hashCode();
 163   }
 164
 165   @Override
 166   public boolean equals(Object obj) {
 167     if (this == obj) return true;
 168     if (obj == null) return false;
 169     if (getClass() != obj.getClass()) return false;
 170     RawValue other = (RawValue) obj;
 171     Object value = getValue();
 172     Object otherValue = other.getValue();
 173     if (value != null) {
 174       if (otherValue != null) {
 175         if (value instanceof byte[]) {
 176           if (otherValue instanceof byte[]) {
 177             return Arrays.equals((byte[]) value, (byte[]) otherValue);
 178           }
 179         } else {
 180           return value.equals(otherValue);
 181         }
 182       }
 183     } else if (otherValue == null) {
 184       return true;
 185     }
 186     return false;
 187   }
 188
 189   @Override
 190   public String toString() {
 191     return "RawValue [value=" + getValue() + "]";
 192   }
 193 }