/**
* 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.tajo.engine.planner.physical;
import org.apache.tajo.storage.Tuple;
import org.apache.tajo.storage.VTuple;
public class HashPartitioner extends Partitioner {
private final Tuple keyTuple;
public HashPartitioner(final int [] keys, final int numPartitions) {
super(keys, numPartitions);
this.keyTuple = new VTuple(partitionKeyIds.length);
}
@Override
public int getPartition(Tuple tuple) {
// In outer join, partition number can be zero because of empty tables.
// So, we should return zero for this case.
if (numPartitions == 0)
return 0;
// build one key tuple
for (int i = 0; i < partitionKeyIds.length; i++) {
keyTuple.put(i, tuple.get(partitionKeyIds[i]));
}
return (keyTuple.hashCode() & Integer.MAX_VALUE) %
(numPartitions == 32 ? numPartitions-1 : numPartitions);
}
}