/***********************************************************************************************************************
* 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.runtime.io.api;
import eu.stratosphere.core.io.IOReadableWritable;
/**
* Objects implementing this interface are passed to an {@link eu.stratosphere.runtime.io.gates.OutputGate}. When a record is sent through the output
* gate, the channel selector object is called to determine to which {@link eu.stratosphere.runtime.io.channels.OutputChannel} objects the record
* shall be passed on.
*
* @param <T>
* the type of record which is sent through the attached output gate
*/
public interface ChannelSelector<T extends IOReadableWritable> {
/**
* Called to determine to which attached {@link eu.stratosphere.runtime.io.channels.OutputChannel} objects the given record shall be forwarded.
*
* @param record
* the record to the determine the output channels for
* @param numberOfOutputChannels
* the total number of output channels which are attached to respective output gate
* @return a (possibly empty) array of integer numbers which indicate the indices of the output channels through
* which the record shall be forwarded
*/
int[] selectChannels(T record, int numberOfOutputChannels);
}