com.google.cloud.datastore

Class Query<V>

java.lang.Object

com.google.cloud.datastore.Query<V>

Type Parameters:

V - the type of the values returned by this query.

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

GqlQuery, StructuredQuery

public abstract class Query<V>
extends Object
implements Serializable

A Google Cloud Datastore query. For usage examples see GqlQuery and StructuredQuery.

Note that queries require proper indexing. See Cloud Datastore Index Configuration for help configuring indexes.

See Also:

Datastore Queries, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Query.ResultType<V> This class represents the expected type of the result.

Method Summary

Methods

Modifier and Type	Method and Description
static EntityQuery.Builder	entityQueryBuilder() Returns a new StructuredQuery builder for full (complete entities) queries.
static <V> GqlQuery.Builder<V>	gqlQueryBuilder(Query.ResultType<V> resultType, String gql) Returns a new GqlQuery builder.
static GqlQuery.Builder<?>	gqlQueryBuilder(String gql) Returns a new GqlQuery builder.
static KeyQuery.Builder	keyQueryBuilder() Returns a new StructuredQuery builder for key only queries.
String	namespace()
static ProjectionEntityQuery.Builder	projectionEntityQueryBuilder() Returns a new StructuredQuery builder for projection queries.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

namespace

public String namespace()

gqlQueryBuilder

public static GqlQuery.Builder<?> gqlQueryBuilder(String gql)

Returns a new GqlQuery builder.

Example of creating and running a GQL query.

 String kind = "my_kind";
 String gqlQuery = "select * from " + kind;
 Query<?> query = Query.gqlQueryBuilder(gqlQuery).build();
 QueryResults<?> results = datastore.run(query);
 // Use results
 

See Also:

GQL Reference

gqlQueryBuilder

public static <V> GqlQuery.Builder<V> gqlQueryBuilder(Query.ResultType<V> resultType,
                                      String gql)

Returns a new GqlQuery builder.

Example of creating and running a typed GQL query.

 String kind = "my_kind";
 String gqlQuery = "select * from " + kind;
 Query<Entity> query = Query.gqlQueryBuilder(Query.ResultType.ENTITY, gqlQuery).build();
 QueryResults<Entity> results = datastore.run(query);
 // Use results
 

See Also:

GQL Reference

entityQueryBuilder

public static EntityQuery.Builder entityQueryBuilder()

Returns a new StructuredQuery builder for full (complete entities) queries.

Example of creating and running an entity query.

 String kind = "my_kind";
 Query<Entity> query = Query.entityQueryBuilder().kind(kind).build();
 QueryResults<Entity> results = datastore.run(query);
 // Use results
 

keyQueryBuilder

public static KeyQuery.Builder keyQueryBuilder()

Returns a new StructuredQuery builder for key only queries.

Example of creating and running a key query.

 String kind = "my_kind";
 Query<Key> query = Query.keyQueryBuilder().kind(kind).build();
 QueryResults<Key> results = datastore.run(query);
 // Use results
 

projectionEntityQueryBuilder

public static ProjectionEntityQuery.Builder projectionEntityQueryBuilder()

Returns a new StructuredQuery builder for projection queries.

Example of creating and running a projection entity query.

 String kind = "my_kind";
 String property = "my_property";
 Query<ProjectionEntity> query = Query.projectionEntityQueryBuilder()
     .kind(kind)
     .addProjection(property)
     .build();
 QueryResults<ProjectionEntity> results = datastore.run(query);
 // Use results