/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
* the License. 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 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
**********************************************************************************************************************/
package eu.stratosphere.api.common.functions;
import java.util.Iterator;
import eu.stratosphere.util.Collector;
public interface GenericCoGrouper<V1, V2, O> extends Function {
/**
* This method must be implemented to provide a user implementation of a
* coGroup. It is called for each two key-value pairs that share the same
* key and come from different inputs.
*
* @param records1 The records from the first input which were paired with the key.
* @param records2 The records from the second input which were paired with the key.
* @param out A collector that collects all output pairs.
*/
void coGroup(Iterator<V1> records1, Iterator<V2> records2, Collector<O> out) throws Exception;
}