com.google.cloud.datastore

Class AggregationQuery

java.lang.Object

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

com.google.cloud.datastore.AggregationQuery

All Implemented Interfaces:

Serializable

@BetaApi
public class AggregationQuery
extends Query<AggregationResults>

An implementation of a Google Cloud Datastore Query that returns AggregationResults, It can be constructed by providing a nested query (StructuredQuery or GqlQuery) to run the aggregations on and a set of Aggregation.

StructuredQuery example:

 EntityQuery selectAllQuery = Query.newEntityQueryBuilder()
    .setKind("Task")
    .build();
 AggregationQuery aggregationQuery = Query.newAggregationQueryBuilder()
    .addAggregation(count().as("total_count"))
    .over(selectAllQuery)
    .build();
 AggregationResults aggregationResults = datastore.runAggregation(aggregationQuery);
 for (AggregationResult aggregationResult : aggregationResults) {
     System.out.println(aggregationResult.get("total_count"));
 }
 

GqlQuery example:

 GqlQuery<?> selectAllGqlQuery = Query.newGqlQueryBuilder(
         "AGGREGATE COUNT(*) AS total_count, COUNT_UP_TO(100) AS count_upto_100 OVER(SELECT * FROM Task)"
     )
     .setAllowLiteral(true)
     .build();
 AggregationQuery aggregationQuery = Query.newAggregationQueryBuilder()
     .over(selectAllGqlQuery)
     .build();
 AggregationResults aggregationResults = datastore.runAggregation(aggregationQuery);
 for (AggregationResult aggregationResult : aggregationResults) {
   System.out.println(aggregationResult.get("total_count"));
   System.out.println(aggregationResult.get("count_upto_100"));
 }
 

See Also:

Datastore queries, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AggregationQuery.Builder
static class	AggregationQuery.Mode

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

Query.ResultType<V>

Method Summary

Modifier and Type	Method and Description
Set<Aggregation>	getAggregations() Returns the Aggregation(s) for this Query.
AggregationQuery.Mode	getMode() Returns the AggregationQuery.Mode for this query.
GqlQuery<?>	getNestedGqlQuery() Returns the underlying for this Query.
StructuredQuery<?>	getNestedStructuredQuery() Returns the underlying for this Query.

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

getNamespace, newAggregationQueryBuilder, newEntityQueryBuilder, newGqlQueryBuilder, newGqlQueryBuilder, newKeyQueryBuilder, newProjectionEntityQueryBuilder

Methods inherited from class java.lang.Object

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

Method Detail

getAggregations

public Set<Aggregation> getAggregations()

Returns the Aggregation(s) for this Query.

getNestedStructuredQuery

public StructuredQuery<?> getNestedStructuredQuery()

Returns the underlying for this Query. Returns null if created with GqlQuery

getNestedGqlQuery

public GqlQuery<?> getNestedGqlQuery()

Returns the underlying for this Query. Returns null if created with StructuredQuery

getMode

public AggregationQuery.Mode getMode()

Returns the AggregationQuery.Mode for this query.