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

   1 package com.google.appengine.api.datastore;
   2
   3 import static com.google.appengine.api.datastore.DataTypeUtils.CheckValueOption.ALLOW_MULTI_VALUE;
   4 import static com.google.appengine.api.datastore.DataTypeUtils.CheckValueOption.VALUE_PRE_CHECKED_WITHOUT_NAME;
   5
   6 import com.google.appengine.api.datastore.DataTypeUtils.CheckValueOption;
   7 import com.google.apphosting.api.AppEngineInternal;
   8
   9 import java.util.EnumSet;
  10 import java.util.Set;
  11
  12 /**
  13  * Internal class that provides utility methods for {@link ExtendableEntity} objects.
  14  *
  15  */
  16 @AppEngineInternal
  17 public final class ExtendableEntityUtil {
  18
  19   /**
  20    * Creates a new {@code Key} with the provided parent and kind. The instantiated
  21    * {@Key} will be incomplete.
  22    *
  23    * @param parent the parent of the key to create, can be {@code null}
  24    * @param kind the kind of the key to create
  25    */
  26   public static Key createKey(Key parent, String kind) {
  27     return new Key(kind, parent);
  28   }
  29
  30   /**
  31    * Check if the input {@code Key} objects are equal (including keys that are
  32    * incomplete).
  33    *
  34    * @param key1 the first input key
  35    * @param key2 the second input key
  36    * @return {@code true} if the keys are equal. {@code false} otherwise.
  37    */
  38   public static boolean areKeysEqual(Key key1, Key key2) {
  39     return key1 == null ? key2 == null : key1.equals(key2, false);
  40   }
  41
  42   /**
  43    * If the specified object cannot be used as the value for a {@code Entity} property, throw
  44    * an exception with the appropriate explanation.
  45    *
  46    * @param propertyName the name of the property.
  47    * @param value value in question
  48    * @param supportedTypes the types considered to be valid types for the value.
  49    * @param valuePreChecked {@code true} if the value without the name has already been checked.
  50    *     {@code false} otherwise.
  51    * @throws IllegalArgumentException if the type is not supported, or if the object is in
  52    * some other way invalid.
  53    */
  54   public static void checkSupportedValue(String propertyName, Object value, boolean valuePreChecked,
  55       Set<Class<?>> supportedTypes) {
  56     EnumSet<CheckValueOption> options = EnumSet.of(ALLOW_MULTI_VALUE);
  57     if (valuePreChecked) {
  58       options.add(VALUE_PRE_CHECKED_WITHOUT_NAME);
  59     }
  60     DataTypeUtils.checkSupportedValue(propertyName, value, options, supportedTypes);
  61   }
  62
  63   private ExtendableEntityUtil() {
  64   }
  65 }