com.google.cloud.datastore

Class StructuredQuery<V>

java.lang.Object

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

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

Type Parameters:

V - the type of the result values this query will produce

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

EntityQuery, KeyQuery, ProjectionEntityQuery

public abstract class StructuredQuery<V>
extends Query<V>

An implementation of a Google Cloud Datastore Query that can be constructed by providing all the specific query elements.

A usage example:

A simple query that returns all entities for a specific kind

 Query<Entity> query = Query.newEntityQueryBuilder().setKind(kind).build();
 QueryResults<Entity> results = datastore.run(query);
 while (results.hasNext()) {
   Entity entity = results.next();
   ...
 }
 

A simple key-only query of all entities for a specific kind

 Query<Key> keyOnlyQuery =  Query.newKeyQueryBuilder().setKind(KIND1).build();
 QueryResults<Key> results = datastore.run(keyOnlyQuery);
 ...
 

A less trivial example of a projection query that returns the first 10 results of "age" and "name" properties (sorted and grouped by "age") with an age greater than 18

 Query<ProjectionEntity> query = Query.newProjectionEntityQueryBuilder()
     .setKind(kind)
     .setProjection(Projection.property("age"), Projection.first("name"))
     .setFilter(PropertyFilter.gt("age", 18))
     .setGroupBy("age")
     .setOrderBy(OrderBy.asc("age"))
     .setLimit(10)
     .build();
 QueryResults<ProjectionEntity> results = datastore.run(query);
 ...
 

See Also:

Datastore queries, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	StructuredQuery.Builder<V> Interface for StructuredQuery builders.
static class	StructuredQuery.CompositeFilter A class representing a filter composed of a combination of other filters.
static class	StructuredQuery.Filter
static class	StructuredQuery.OrderBy
static class	StructuredQuery.PropertyFilter A class representing a filter based on a single property or ancestor.

Nested classes/interfaces inherited from class com.google.cloud.datastore.Query

Query.ResultType<V>

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
List<String>	getDistinctOn() Returns the distinct on clause for this query.
Cursor	getEndCursor() Returns the end cursor for this query.
StructuredQuery.Filter	getFilter() Returns the filter for this query.
String	getKind() Returns the kind for this query.
Integer	getLimit() Returns the limit for this query.
int	getOffset() Returns the offset for this query.
List<StructuredQuery.OrderBy>	getOrderBy() Returns the order by clause for this query.
List<String>	getProjection() Returns the projection for this query.
Cursor	getStartCursor() Returns the start cursor for this query.
int	hashCode()
abstract StructuredQuery.Builder<V>	toBuilder()
String	toString()

Methods inherited from class com.google.cloud.datastore.Query

getNamespace, newEntityQueryBuilder, newGqlQueryBuilder, newGqlQueryBuilder, newKeyQueryBuilder, newProjectionEntityQueryBuilder

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

getKind

public String getKind()

Returns the kind for this query.

getProjection

public List<String> getProjection()

Returns the projection for this query.

getFilter

public StructuredQuery.Filter getFilter()

Returns the filter for this query.

getDistinctOn

public List<String> getDistinctOn()

Returns the distinct on clause for this query.

getOrderBy

public List<StructuredQuery.OrderBy> getOrderBy()

Returns the order by clause for this query.

getStartCursor

public Cursor getStartCursor()

Returns the start cursor for this query.

getEndCursor

public Cursor getEndCursor()

Returns the end cursor for this query.

getOffset

public int getOffset()

Returns the offset for this query.

getLimit

public Integer getLimit()

Returns the limit for this query.

toBuilder

public abstract StructuredQuery.Builder<V> toBuilder()