org.elasticsearch.search.aggregations.AggregatorFactory Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
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* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.search.aggregations;
import org.elasticsearch.search.aggregations.support.AggregationContext;
/**
* A factory that knows how to create an {@link Aggregator} of a specific type.
*/
public abstract class AggregatorFactory {
protected String name;
protected String type;
protected AggregatorFactory parent;
protected AggregatorFactories factories = AggregatorFactories.EMPTY;
/**
* Constructs a new aggregator factory.
*
* @param name The aggregation name
* @param type The aggregation type
*/
public AggregatorFactory(String name, String type) {
this.name = name;
this.type = type;
}
/**
* Registers sub-factories with this factory. The sub-factory will be responsible for the creation of sub-aggregators under the
* aggregator created by this factory.
*
* @param subFactories The sub-factories
* @return this factory (fluent interface)
*/
public AggregatorFactory subFactories(AggregatorFactories subFactories) {
this.factories = subFactories;
this.factories.setParent(this);
return this;
}
/**
* Validates the state of this factory (makes sure the factory is properly configured)
*/
public final void validate() {
doValidate();
factories.validate();
}
/**
* @return The parent factory if one exists (will always return {@code null} for top level aggregator factories).
*/
public AggregatorFactory parent() {
return parent;
}
/**
* Creates the aggregator
*
* @param context The aggregation context
* @param parent The parent aggregator (if this is a top level factory, the parent will be {@code null})
* @param expectedBucketsCount If this is a sub-factory of another factory, this will indicate the number of bucket the parent aggregator
* may generate (this is an estimation only). For top level factories, this will always be 0
*
* @return The created aggregator
*/
public abstract Aggregator create(AggregationContext context, Aggregator parent, long expectedBucketsCount);
public void doValidate() {
}
}