/*
* 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.giraph.hive.input.edge;
import org.apache.giraph.io.iterables.EdgeWithSource;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import com.facebook.giraph.hive.record.HiveReadableRecord;
import java.util.Iterator;
/**
* Simple implementation of {@link HiveToEdge} when each edge is in the one
* row of the input.
*
* @param <I> Vertex id
* @param <E> Edge data
*/
public abstract class SimpleHiveToEdge<I extends WritableComparable,
E extends Writable> extends AbstractHiveToEdge<I, E> {
/** Iterator over input records */
private Iterator<HiveReadableRecord> records;
/** Reusable {@link EdgeWithSource} object */
private EdgeWithSource<I, E> reusableEdge = new EdgeWithSource<I, E>();
/**
* Read source vertex ID from Hive record
*
* @param hiveRecord HiveRecord to read from
* @return source vertex ID
*/
public abstract I getSourceVertexId(HiveReadableRecord hiveRecord);
/**
* Read target vertex ID from Hive record
*
* @param hiveRecord HiveRecord to read from
* @return target vertex ID
*/
public abstract I getTargetVertexId(HiveReadableRecord hiveRecord);
/**
* Read edge value from the Hive record.
*
* @param hiveRecord HiveRecord to read from
* @return Edge value
*/
public abstract E getEdgeValue(HiveReadableRecord hiveRecord);
@Override
public final void initializeRecords(Iterator<HiveReadableRecord> records) {
this.records = records;
reusableEdge.setEdge(getConf().createReusableEdge());
}
@Override
public boolean hasNext() {
return records.hasNext();
}
@Override
public EdgeWithSource<I, E> next() {
HiveReadableRecord record = records.next();
reusableEdge.setSourceVertexId(getSourceVertexId(record));
reusableEdge.setTargetVertexId(getTargetVertexId(record));
reusableEdge.setEdgeValue(getEdgeValue(record));
return reusableEdge;
}
}