com.google.appengine.api.datastore.Query.FilterOperator Java Examples

@Test
public void queryInterface_orFilter_printsMatchedEntities() throws Exception {
  // Arrange
  Entity a = new Entity("Person", "a");
  a.setProperty("height", 100);
  Entity b = new Entity("Person", "b");
  b.setProperty("height", 150);
  Entity c = new Entity("Person", "c");
  c.setProperty("height", 200);
  datastore.put(ImmutableList.<Entity>of(a, b, c));

  StringWriter buf = new StringWriter();
  PrintWriter out = new PrintWriter(buf);
  long minHeight = 125;
  long maxHeight = 175;

  // Act
  // [START gae_java8_datastore_interface_3]
  Filter tooShortFilter = new FilterPredicate("height", FilterOperator.LESS_THAN, minHeight);

  Filter tooTallFilter = new FilterPredicate("height", FilterOperator.GREATER_THAN, maxHeight);

  Filter heightOutOfRangeFilter = CompositeFilterOperator.or(tooShortFilter, tooTallFilter);

  Query q = new Query("Person").setFilter(heightOutOfRangeFilter);
  // [END gae_java8_datastore_interface_3]

  // Assert
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(a, c);
}
 

@Test
public void queryRestrictions_surprisingMultipleValuesAllMustMatch_returnsNoEntities()
    throws Exception {
  Entity a = new Entity("Widget", "a");
  List<Long> xs = Arrays.asList(1L, 2L);
  a.setProperty("x", xs);
  datastore.put(a);

  // [START gae_java8_datastore_surprising_behavior_1]
  Query q =
      new Query("Widget")
          .setFilter(
              CompositeFilterOperator.and(
                  new FilterPredicate("x", FilterOperator.GREATER_THAN, 1),
                  new FilterPredicate("x", FilterOperator.LESS_THAN, 2)));
  // [END gae_java8_datastore_surprising_behavior_1]

  // Entity "a" will not match because no individual value matches all filters.
  // See the documentation for more details:
  // https://cloud.google.com/appengine/docs/java/datastore/query-restrictions
  // #properties_with_multiple_values_can_behave_in_surprising_ways
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).isEmpty();
}
 

protected void deleteSessionWithValue(String varName, String varValue) {
  Transaction transaction = datastore.beginTransaction();
  try {
    Query query = new Query(SESSION_KIND)
        .setFilter(new FilterPredicate(varName, FilterOperator.EQUAL, varValue));
    Iterator<Entity> results = datastore.prepare(transaction, query).asIterator();
    while (results.hasNext()) {
      Entity stateEntity = results.next();
      datastore.delete(transaction, stateEntity.getKey());
    }
    transaction.commit();
  } finally {
    if (transaction.isActive()) {
      transaction.rollback();
    }
  }
}
 

protected void deleteSessionWithValue(String varName, String varValue) {
  Transaction transaction = datastore.beginTransaction();
  try {
    Query query = new Query(SESSION_KIND)
        .setFilter(new FilterPredicate(varName, FilterOperator.EQUAL, varValue));
    Iterator<Entity> results = datastore.prepare(transaction, query).asIterator();
    while (results.hasNext()) {
      Entity stateEntity = results.next();
      datastore.delete(transaction, stateEntity.getKey());
    }
    transaction.commit();
  } finally {
    if (transaction.isActive()) {
      transaction.rollback();
    }
  }
}
 

protected void deleteSessionWithValue(String varName, String varValue) {
  Transaction transaction = datastore.beginTransaction();
  try {
    Query query = new Query(SESSION_KIND)
        .setFilter(new FilterPredicate(varName, FilterOperator.EQUAL, varValue));
    Iterator<Entity> results = datastore.prepare(transaction, query).asIterator();
    while (results.hasNext()) {
      Entity stateEntity = results.next();
      datastore.delete(transaction, stateEntity.getKey());
    }
    transaction.commit();
  } finally {
    if (transaction.isActive()) {
      transaction.rollback();
    }
  }
}
 

protected void deleteSessionWithValue(String varName, String varValue) {
  Transaction transaction = datastore.beginTransaction();
  try {
    Query query = new Query(SESSION_KIND)
        .setFilter(new FilterPredicate(varName, FilterOperator.EQUAL, varValue));
    Iterator<Entity> results = datastore.prepare(transaction, query).asIterator();
    while (results.hasNext()) {
      Entity stateEntity = results.next();
      datastore.delete(transaction, stateEntity.getKey());
    }
    transaction.commit();
  } finally {
    if (transaction.isActive()) {
      transaction.rollback();
    }
  }
}
 

/**
 * Returns the Account key associated with the specified user.
 * @param pm   reference to the persistence manager
 * @param user user to return the account key for
 * @return the Account key associated with the specified user; or <code>null</code> if no account is associated with the specified user
 */
public static Key getAccountKeyByUser( final PersistenceManager pm, final User user ) {
	final String memcacheKey = CACHE_KEY_USER_ACCOUNT_KEY_PREFIX + user.getEmail();
	final String accountKeyString = (String) memcacheService.get( memcacheKey );
	if ( accountKeyString != null )
		return KeyFactory.stringToKey( accountKeyString );
	
	final Query q = new Query( Account.class.getSimpleName() );
	q.setFilter( new FilterPredicate( "user", FilterOperator.EQUAL, user ) );
	q.setKeysOnly();
	final List< Entity > entityList = DatastoreServiceFactory.getDatastoreService().prepare( q ).asList( FetchOptions.Builder.withDefaults() );
	if ( entityList.isEmpty() )
		return null;
	
	final Key accountKey = entityList.get( 0 ).getKey();
	try {
		memcacheService.put( memcacheKey, KeyFactory.keyToString( accountKey ) );
	}
	catch ( final MemcacheServiceException mse ) {
		LOGGER.log( Level.WARNING, "Failed to put key to memcache: " + memcacheKey, mse );
		// Ignore memcache errors, do not prevent serving user request
	}
	
	return accountKey;
}
 

@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws IOException, ServletException {
  // [START exploding_index_example_1]
  Query q =
      new Query("Widget")
          .setFilter(
              CompositeFilterOperator.and(
                  new FilterPredicate("x", FilterOperator.EQUAL, 1),
                  new FilterPredicate("y", FilterOperator.EQUAL, 2)))
          .addSort("date", Query.SortDirection.ASCENDING);
  // [END exploding_index_example_1]
  List<Entity> results = datastore.prepare(q).asList(FetchOptions.Builder.withDefaults());

  PrintWriter out = resp.getWriter();
  out.printf("Got %d widgets.\n", results.size());
}
 

/**
 * Returns the Account key associated with the specified authorization key.
 * @param pm               reference to the persistence manager
 * @param authorizationKey authorization key to return the account key for
 * @return the Account key associated with the specified authorization key; or <code>null</code> if the authorization key is invalid
 */
public static Key getAccountKeyByAuthKey( final PersistenceManager pm, final String authorizationKey ) {
	final String memcacheKey = CACHE_KEY_AUTH_KEY_ACCOUNT_KEY_PREFIX + authorizationKey;
	final String accountKeyString = (String) memcacheService.get( memcacheKey );
	if ( accountKeyString != null )
		return KeyFactory.stringToKey( accountKeyString );
	
	final Query q = new Query( Account.class.getSimpleName() );
	q.setFilter( new FilterPredicate( "authorizationKey", FilterOperator.EQUAL, authorizationKey ) );
	q.setKeysOnly();
	final List< Entity > entityList = DatastoreServiceFactory.getDatastoreService().prepare( q ).asList( FetchOptions.Builder.withDefaults() );
	if ( entityList.isEmpty() )
		return null;
	
	final Key accountKey = entityList.get( 0 ).getKey();
	try {
		memcacheService.put( memcacheKey, KeyFactory.keyToString( accountKey ) );
	}
	catch ( final MemcacheServiceException mse ) {
		LOGGER.log( Level.WARNING, "Failed to put key to memcache: " + memcacheKey, mse );
		// Ignore memcache errors, do not prevent serving user request
	}
	
	return accountKey;
}
 

@Test
public void testPropertyMetadata() {
    NamespaceManager.set(namespaceDat[2]);
    // sort by kind/property, kindDat[1] < kindDat[0] < kindDat[2]
    Query q = new Query("__property__").addSort(Entity.KEY_RESERVED_PROPERTY).setKeysOnly();
    // filter out properties for kind "testing"
    Key key1 = Entities.createPropertyKey(kindDat[0], "urlData");
    Key key2 = Entities.createPropertyKey(kindDat[2], "urlData");
    q.setFilter(CompositeFilterOperator.and(
        new FilterPredicate(Entity.KEY_RESERVED_PROPERTY, FilterOperator.GREATER_THAN, key1),
        new FilterPredicate(Entity.KEY_RESERVED_PROPERTY, FilterOperator.LESS_THAN_OR_EQUAL, key2)));
    List<Entity> el = service.prepare(q).asList(fo);
    // un-indexed property, textData, will not be returned in __property__ queries.
    assertEquals(13, el.size());
    for (int i = 0; i < el.size(); i++) {
        assertEquals(namespaceDat[2], el.get(i).getKey().getNamespace());
        assertEquals(kindDat[2], el.get(i).getKey().getParent().getName());
        if (i == 0) {
            assertEquals("adressData", el.get(0).getKey().getName());
        } else if (i == el.size() - 1) {
            assertEquals("urlData", el.get(el.size() - 1).getKey().getName());
        }
    }
}
 

@Test
public void testKindMetadata() {
    // check non empty namespace only
    for (int i = 1; i < namespaceDat.length; i++) {
        NamespaceManager.set(namespaceDat[i]);
        Query q = new Query("__kind__").addSort(Entity.KEY_RESERVED_PROPERTY);
        int count = 0;
        for (Entity e : service.prepare(q).asIterable()) {
            // do not count those stats entities for namespace.
            if (!e.getKey().getName().startsWith("__Stat_Ns_")) {
                count++;
            }
        }
        // For each namespace, only 3 user defined kinds.
        assertEquals(3, count);
        // check a specified namespace
        Key key1 = Entities.createKindKey("testing");
        q.setFilter(new FilterPredicate(Entity.KEY_RESERVED_PROPERTY, FilterOperator.EQUAL, key1));
        assertEquals(1, service.prepare(q).countEntities(fo));
        Entity ke = service.prepare(q).asSingleEntity();
        assertEquals("testing", ke.getKey().getName());
        assertEquals(namespaceDat[i], ke.getKey().getNamespace());
        assertEquals(namespaceDat[i], ke.getNamespace());
    }
}
 

@Test
public void propertyFilterExample_returnsMatchingEntities() throws Exception {
  // Arrange
  Entity p1 = new Entity("Person");
  p1.setProperty("height", 120);
  Entity p2 = new Entity("Person");
  p2.setProperty("height", 180);
  Entity p3 = new Entity("Person");
  p3.setProperty("height", 160);
  datastore.put(ImmutableList.<Entity>of(p1, p2, p3));

  // Act
  long minHeight = 160;
  // [START gae_java8_datastore_property_filter]
  Filter propertyFilter =
      new FilterPredicate("height", FilterOperator.GREATER_THAN_OR_EQUAL, minHeight);
  Query q = new Query("Person").setFilter(propertyFilter);
  // [END gae_java8_datastore_property_filter]

  // Assert
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(p2, p3);
}
 

@Test
public void queryInterface_singleFilter_returnsMatchedEntities() throws Exception {
  // Arrange
  Entity a = new Entity("Person", "a");
  a.setProperty("height", 100);
  Entity b = new Entity("Person", "b");
  b.setProperty("height", 150);
  Entity c = new Entity("Person", "c");
  c.setProperty("height", 300);
  datastore.put(ImmutableList.<Entity>of(a, b, c));

  // Act
  long minHeight = 150;
  // [START gae_java8_datastore_interface_2]
  Filter heightMinFilter =
      new FilterPredicate("height", FilterOperator.GREATER_THAN_OR_EQUAL, minHeight);

  Query q = new Query("Person").setFilter(heightMinFilter);
  // [END gae_java8_datastore_interface_2]

  // Assert
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(b, c);
}
 

@Test
public void queryRestrictions_compositeFilter_isInvalid() throws Exception {
  long minBirthYear = 1940;
  long maxHeight = 200;
  // [START gae_java8_datastore_inequality_filters_one_property_invalid]
  Filter birthYearMinFilter =
      new FilterPredicate("birthYear", FilterOperator.GREATER_THAN_OR_EQUAL, minBirthYear);

  Filter heightMaxFilter =
      new FilterPredicate("height", FilterOperator.LESS_THAN_OR_EQUAL, maxHeight);

  Filter invalidFilter = CompositeFilterOperator.and(birthYearMinFilter, heightMaxFilter);

  Query q = new Query("Person").setFilter(invalidFilter);
  // [END gae_java8_datastore_inequality_filters_one_property_invalid]

  // Note: The local devserver behavior is different than the production
  // version of Cloud Datastore, so there aren't any assertions we can make
  // in this test.  The query appears to work with the local test runner,
  // but will fail in production.
}
 

@Test
public void queryRestrictions_missingSortOnInequality_isInvalid() throws Exception {
  long minBirthYear = 1940;
  // [START gae_java8_datastore_inequality_filters_sort_orders_invalid_1]
  Filter birthYearMinFilter =
      new FilterPredicate("birthYear", FilterOperator.GREATER_THAN_OR_EQUAL, minBirthYear);

  // Not valid. Missing sort on birthYear.
  Query q =
      new Query("Person")
          .setFilter(birthYearMinFilter)
          .addSort("lastName", SortDirection.ASCENDING);
  // [END gae_java8_datastore_inequality_filters_sort_orders_invalid_1]

  // Note: The local devserver behavior is different than the production
  // version of Cloud Datastore, so there aren't any assertions we can make
  // in this test.  The query appears to work with the local test runner,
  // but will fail in production.
}
 

@Test
public void queryRestrictions_sortWrongOrderOnInequality_isInvalid() throws Exception {
  long minBirthYear = 1940;
  // [START gae_java8_datastore_inequality_filters_sort_orders_invalid_2]
  Filter birthYearMinFilter =
      new FilterPredicate("birthYear", FilterOperator.GREATER_THAN_OR_EQUAL, minBirthYear);

  // Not valid. Sort on birthYear needs to be first.
  Query q =
      new Query("Person")
          .setFilter(birthYearMinFilter)
          .addSort("lastName", SortDirection.ASCENDING)
          .addSort("birthYear", SortDirection.ASCENDING);
  // [END gae_java8_datastore_inequality_filters_sort_orders_invalid_2]

  // Note: The local devserver behavior is different than the production
  // version of Cloud Datastore, so there aren't any assertions we can make
  // in this test.  The query appears to work with the local test runner,
  // but will fail in production.
}
 

@Test
@InSequence(4)
public void testStep4BigAsIterator() {
    Query q = new Query(kindName, rootKey);
    q.setFilter(new FilterPredicate("count", FilterOperator.LESS_THAN, bigCount));
    Iterator<Entity> eData = service.prepare(q).asIterator(fo);
    assertEquals(bigCount, getSize(eData));
}
 

@Override
public Iterable<Photo> getActivePhotos() {
  Query query = new Query(getKind());
  Query.Filter filter = new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_ACTIVE,
      FilterOperator.EQUAL, true);
  query.addSort(PhotoNoSql.FIELD_NAME_UPLOAD_TIME, SortDirection.DESCENDING);
  query.setFilter(filter);
  FetchOptions options = FetchOptions.Builder.withDefaults();
  return queryEntities(query, options);
}
 

@Test
@InSequence(9)
public void testStep9BigFilterIn() {
    int filterNum = 500;
    Query q = new Query(kindName, rootKey);
    q.setFilter(new FilterPredicate("count", FilterOperator.IN, getFilterIn(filterNum)));
    FetchOptions fo = FetchOptions.Builder.withDefaults();
    int ttl = service.prepare(q).countEntities(fo);
    assertEquals(filterNum, ttl);
}
 

private void doCleanup() {
  log.log(Level.INFO, "Starting a job to clean up processed notification records");

  DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();

  Calendar cutoffTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
  cutoffTime.add(Calendar.HOUR, -HOURS_TO_KEEP_RECORDS_OF_PROCESSED_NOTIFICATIONS);

  Query query = new Query(Worker.PROCESSED_NOTIFICATION_TASKS_ENTITY_KIND)
    .setFilter(new FilterPredicate("processedAt", FilterOperator.LESS_THAN, cutoffTime.getTime()))
    .setKeysOnly();

  PreparedQuery preparedQuery = datastore.prepare(query);

  // Delete in batches
  List<Entity> entitiesToBeDeleted = null;
  do {
    entitiesToBeDeleted = preparedQuery.asList(FetchOptions.Builder.withLimit(5));

    List<Key> keys = new ArrayList<Key>();

    for (Entity entity : entitiesToBeDeleted) {
      keys.add(entity.getKey());
    }

    datastore.delete(keys);
  } while (entitiesToBeDeleted.size() > 0);

  log.log(Level.INFO, "Finished a job to clean up processed notification records");
}
 

@Test
public void testNamespaceMetadata() {
    NamespaceManager.set(""); // TODO -- shouldn't Entities.createNamespaceKey already do this by default?
    Query q = new Query("__namespace__").addSort(Entity.KEY_RESERVED_PROPERTY);
    Key key1 = Entities.createNamespaceKey(namespaceDat[1]);
    Key key2 = Entities.createNamespaceKey(namespaceDat[2]);
    q.setFilter(new FilterPredicate(Entity.KEY_RESERVED_PROPERTY, FilterOperator.IN, Arrays.asList(key1, key2)));
    List<Entity> ns = service.prepare(q).asList(fo);
    assertEquals(2, ns.size());

    for (int i = 0; i < ns.size(); i++) {
        assertEquals(namespaceDat[i + 1], ns.get(i).getKey().getName());
    }
}
 

/**
 * Deletes all device subscription entities continuously using task push queue.
 *
 * @param time Threshold time before which entities created will be deleted. If time is null,
 *             current time is used and set as Threshold time.
 * @param cursor Query cursor indicates last query result set position
 */
protected void deleteAllContinuously(Date time, String cursor) {
  if (time == null) {
    time = Calendar.getInstance(TimeZone.getTimeZone("UTC")).getTime();
  }

  Query.FilterPredicate timeFilter = new Query.FilterPredicate(PROPERTY_TIMESTAMP,
      FilterOperator.LESS_THAN_OR_EQUAL, time);
  QueryResultIterable<Entity> entities;
  List<Key> keys = new ArrayList<Key> ();
  List<String> subIds = new ArrayList<String> ();
  Query queryAll;

  queryAll = new Query(DeviceSubscription.SUBSCRIPTION_KIND).setFilter(timeFilter);
  FetchOptions options = FetchOptions.Builder.withLimit(BATCH_DELETE_SIZE);
  if (!StringUtility.isNullOrEmpty(cursor)) {
    options.startCursor(Cursor.fromWebSafeString(cursor));
  }

  entities = this.datastoreService.prepare(queryAll).asQueryResultIterable(options);
  if (entities != null && entities.iterator() != null) {
    for (Entity entity : entities) {
      keys.add(entity.getKey());
      String[] ids = new Gson().fromJson((String) entity.getProperty(PROPERTY_SUBSCRIPTION_IDS),
          String[].class);
      subIds.addAll(Arrays.asList(ids));
    }
  }

  if (keys.size() > 0) {
    deleteInBatch(keys);
    enqueueDeleteDeviceSubscription(time, entities.iterator().getCursor().toWebSafeString());
  }
  if (subIds.size() > 0) {
    deletePsiSubscriptions(subIds);
  }
}
 

private Entity retrievePersonWithLastName(String targetLastName) {
  // [START gae_java8_datastore_single_retrieval]
  Query q =
      new Query("Person")
          .setFilter(new FilterPredicate("lastName", FilterOperator.EQUAL, targetLastName));

  PreparedQuery pq = datastore.prepare(q);
  Entity result = pq.asSingleEntity();
  // [END gae_java8_datastore_single_retrieval]
  return result;
}
 

@Override
public Iterable<Photo> getOwnedPhotos(String userId) {
  Query query = new Query(getKind());
  query.setAncestor(userManager.createDemoUserKey(userId));
  Query.Filter filter = new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_ACTIVE,
      FilterOperator.EQUAL, true);
  query.setFilter(filter);
  FetchOptions options = FetchOptions.Builder.withDefaults();
  return queryEntities(query, options);
}
 

@Test
public void queryRestrictions_surprisingMultipleValuesTwoNotEquals_returnsMatchedEntities()
    throws Exception {
  Entity a = new Entity("Widget", "a");
  a.setProperty("x", ImmutableList.<Long>of(1L, 2L));
  Entity b = new Entity("Widget", "b");
  b.setProperty("x", ImmutableList.<Long>of(1L, 2L, 3L));
  datastore.put(ImmutableList.<Entity>of(a, b));

  // [START gae_java8_datastore_surprising_behavior_4]
  Query q =
      new Query("Widget")
          .setFilter(
              CompositeFilterOperator.and(
                  new FilterPredicate("x", FilterOperator.NOT_EQUAL, 1),
                  new FilterPredicate("x", FilterOperator.NOT_EQUAL, 2)));
  // [END gae_java8_datastore_surprising_behavior_4]

  // The two NOT_EQUAL filters in the query become like the combination of queries:
  // x < 1 OR (x > 1 AND x < 2) OR x > 2
  //
  // Only "b" has some value which matches the "x > 2" portion of this query.
  //
  // See the documentation for more details:
  // https://cloud.google.com/appengine/docs/java/datastore/query-restrictions
  // #properties_with_multiple_values_can_behave_in_surprising_ways
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(b);
}
 

@Override
public Iterable<Photo> getSharedPhotos(String userId) {
  Query query = new Query(getKind());
  Query.Filter ownerFilter =
      new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_OWNER_ID, FilterOperator.NOT_EQUAL, userId);
  List<Query.Filter> filterList =
      Arrays.asList(ownerFilter,
          new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_SHARED, FilterOperator.EQUAL, true),
          new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_ACTIVE, FilterOperator.EQUAL, true)
          );
  Filter filter = new Query.CompositeFilter(CompositeFilterOperator.AND, filterList);
  query.setFilter(filter);
  FetchOptions options = FetchOptions.Builder.withDefaults();
  return queryEntities(query, options);
}
 

@Test
public void queryRestrictions_surprisingMultipleValuesNotEquals_returnsMatchedEntities()
    throws Exception {
  Entity a = new Entity("Widget", "a");
  a.setProperty("x", ImmutableList.<Long>of(1L, 2L));
  Entity b = new Entity("Widget", "b");
  b.setProperty("x", ImmutableList.<Long>of(1L, 3L));
  Entity c = new Entity("Widget", "c");
  c.setProperty("x", ImmutableList.<Long>of(-6L, 2L));
  Entity d = new Entity("Widget", "d");
  d.setProperty("x", ImmutableList.<Long>of(-6L, 4L));
  Entity e = new Entity("Widget", "e");
  e.setProperty("x", ImmutableList.<Long>of(1L));
  datastore.put(ImmutableList.<Entity>of(a, b, c, d, e));

  // [START gae_java8_datastore_surprising_behavior_3]
  Query q = new Query("Widget").setFilter(new FilterPredicate("x", FilterOperator.NOT_EQUAL, 1));
  // [END gae_java8_datastore_surprising_behavior_3]

  // The query matches any entity that has a some value other than 1. Only
  // entity "e" is not matched.  See the documentation for more details:
  // https://cloud.google.com/appengine/docs/java/datastore/query-restrictions
  // #properties_with_multiple_values_can_behave_in_surprising_ways
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(a, b, c, d);
}
 

@Test
public void queryRestrictions_surprisingMultipleValuesEquals_returnsMatchedEntities()
    throws Exception {
  Entity a = new Entity("Widget", "a");
  a.setProperty("x", ImmutableList.<Long>of(1L, 2L));
  Entity b = new Entity("Widget", "b");
  b.setProperty("x", ImmutableList.<Long>of(1L, 3L));
  Entity c = new Entity("Widget", "c");
  c.setProperty("x", ImmutableList.<Long>of(-6L, 2L));
  Entity d = new Entity("Widget", "d");
  d.setProperty("x", ImmutableList.<Long>of(-6L, 4L));
  Entity e = new Entity("Widget", "e");
  e.setProperty("x", ImmutableList.<Long>of(1L, 2L, 3L));
  datastore.put(ImmutableList.<Entity>of(a, b, c, d, e));

  // [START gae_java8_datastore_surprising_behavior_2]
  Query q =
      new Query("Widget")
          .setFilter(
              CompositeFilterOperator.and(
                  new FilterPredicate("x", FilterOperator.EQUAL, 1),
                  new FilterPredicate("x", FilterOperator.EQUAL, 2)));
  // [END gae_java8_datastore_surprising_behavior_2]

  // Only "a" and "e" have both 1 and 2 in the "x" array-valued property.
  // See the documentation for more details:
  // https://cloud.google.com/appengine/docs/java/datastore/query-restrictions
  // #properties_with_multiple_values_can_behave_in_surprising_ways
  List<Entity> results =
      datastore.prepare(q.setKeysOnly()).asList(FetchOptions.Builder.withDefaults());
  assertWithMessage("query results").that(results).containsExactly(a, e);
}
 

@Override
public Iterable<Photo> getDeactivedPhotos() {
  Query query = new Query(getKind());
  Query.Filter filter = new Query.FilterPredicate(PhotoNoSql.FIELD_NAME_ACTIVE,
      FilterOperator.EQUAL, false);
  query.setFilter(filter);
  FetchOptions options = FetchOptions.Builder.withDefaults();
  return queryEntities(query, options);
}
 

private void doCleanup() {
  log.log(Level.INFO, "Starting a job to clean up processed notification records");
  
  DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();

  Calendar cutoffTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
  cutoffTime.add(Calendar.HOUR, -HOURS_TO_KEEP_RECORDS_OF_PROCESSED_NOTIFICATIONS);
  
  Query query = new Query(PushNotificationWorker.PROCESSED_NOTIFICATION_TASKS_ENTITY_KIND)
    .setFilter(new FilterPredicate("processedAt", FilterOperator.LESS_THAN, cutoffTime.getTime()))
    .setKeysOnly();
  
  PreparedQuery preparedQuery = datastore.prepare(query);

  // Delete in batches
  List<Entity> entitiesToBeDeleted = null;
  do {
    entitiesToBeDeleted = preparedQuery.asList(FetchOptions.Builder.withLimit(5));
    
    List<Key> keys = new ArrayList<Key>();
    
    for (Entity entity : entitiesToBeDeleted) {
      keys.add(entity.getKey());
    }
  
    datastore.delete(keys);
  } while (entitiesToBeDeleted.size() > 0);

  log.log(Level.INFO, "Finished a job to clean up processed notification records");
}