/**
* (c) Copyright 2012 WibiData, Inc.
*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
* 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 org.kiji.mapreduce.avro;
import java.io.IOException;
import org.apache.avro.Schema;
import org.kiji.annotations.ApiAudience;
import org.kiji.annotations.ApiStability;
import org.kiji.annotations.Inheritance;
/**
* Kiji analytic functions (mappers, reducers, producer, gatherers, etc.) that output
* {@link org.apache.avro.mapred.AvroKey} objects are required to implement this interface
* as a means of specifying the Avro writer schema for their output key data.
*/
@ApiAudience.Public
@ApiStability.Stable
@Inheritance.Extensible
public interface AvroKeyWriter {
/**
* If the output key class is {@link org.apache.avro.mapred.AvroKey}, the Kiji framework
* will call this method to determine what the wrapped datum's writer schema is.
*
* <p>If this class does not use an AvroKey as its output key class, the return value from
* this method will not be used. It may be null.</p>
*
* @throws IOException If there is an error.
* @return The Avro schema of the datum wrapped in the AvroKey output.
*/
Schema getAvroKeyWriterSchema() throws IOException;
}