io.trino.plugin.accumulo.iterators.MaxByteArrayCombiner Maven / Gradle / Ivy
/*
* 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 io.trino.plugin.accumulo.iterators;
import com.google.common.primitives.UnsignedBytes;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.Value;
import org.apache.accumulo.core.iterators.Combiner;
import java.util.Comparator;
import java.util.Iterator;
/**
* A Combiner that does a lexicographic compare against values, returning the 'largest' value
*/
public class MaxByteArrayCombiner
extends Combiner
{
private final Comparator comparator = UnsignedBytes.lexicographicalComparator();
@Override
public Value reduce(Key key, Iterator iter)
{
Value max = null;
while (iter.hasNext()) {
Value test = iter.next();
if (max == null) {
max = new Value(test.get());
}
else if (comparator.compare(test.get(), max.get()) > 0) {
max.set(test.get());
}
}
return max;
}
}