CollectMinUDAF.java

package brickhouse.udf.collect;

import brickhouse.udf.collect.CollectMaxUDAF.MapCollectMaxUDAFEvaluator;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;


@Description(name = "collect_min",
        value = "_FUNC_(x, val, n) - Returns an map of the N min numeric values in the aggregation group "
)
public class CollectMinUDAF extends AbstractGenericUDAFResolver {

    @Override
    public GenericUDAFEvaluator getEvaluator(TypeInfo[] parameters)
            throws SemanticException {
        return new MapCollectMinUDAFEvaluator();
    }

    public static class MapCollectMinUDAFEvaluator extends MapCollectMaxUDAFEvaluator {

        public MapCollectMinUDAFEvaluator() {
            super(false);
        }
    }

}