/*
* 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.filter;
import java.io.IOException;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.jena.hadoop.rdf.mapreduce.RdfMapReduceConstants;
import org.apache.jena.hadoop.rdf.types.AbstractNodeTupleWritable;
/**
* Abstract mapper implementation which helps in filtering tuples from the
* input, derived implementations provide an implementation of the
* {@link #accepts(TKey, T)}
*
*
*
* @param <TKey>
* Key type
* @param <TValue>
* Tuple type
* @param <T>
* Writable tuple type
*/
@SuppressWarnings("javadoc")
public abstract class AbstractNodeTupleFilterMapper<TKey, TValue, T extends AbstractNodeTupleWritable<TValue>> extends
Mapper<TKey, T, TKey, T> {
private boolean invert = false;
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
this.invert = context.getConfiguration().getBoolean(RdfMapReduceConstants.FILTER_INVERT, this.invert);
}
@Override
protected final void map(TKey key, T value, Context context) throws IOException, InterruptedException {
if (this.accepts(key, value)) {
if (!this.invert)
context.write(key, value);
} else if (this.invert) {
context.write(key, value);
}
}
/**
* Gets whether the mapper accepts the key value pair and will pass it as
* output
*
* @param key
* Key
* @param tuple
* Tuple value
* @return True if the mapper accepts the given key value pair, false
* otherwise
*/
protected abstract boolean accepts(TKey key, T tuple);
}