/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.jena.hadoop.rdf.mapreduce;
import java.io.IOException;
import org.apache.hadoop.mapreduce.Mapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A mapper which discards the key replacing it with the value
*
*
* @param <TKey> Key type
* @param <TValue> Value type
*/
public class ValueMapper<TKey, TValue> extends Mapper<TKey, TValue, TValue, TValue> {
private static final Logger LOG = LoggerFactory.getLogger(ValueMapper.class);
private boolean tracing = false;
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
this.tracing = LOG.isTraceEnabled();
}
@Override
protected void map(TKey key, TValue value, Context context) throws IOException,
InterruptedException {
if (this.tracing) {
LOG.trace("Value = {}", value);
}
context.write(value, value);
}
}