/**
 * 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.hadoop.hive.ql.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;

/**
 * UDFAbs.
 *
 */
@Description(name = "abs",
    value = "_FUNC_(x) - returns the absolute value of x",
    extended = "Example:\n"
    + "  > SELECT _FUNC_(0) FROM src LIMIT 1;\n"
    + "  0\n"
    + "  > SELECT _FUNC_(-5) FROM src LIMIT 1;\n" + "  5")
public class UDFAbs extends UDF {
  private final DoubleWritable resultDouble = new DoubleWritable();
  private final LongWritable resultLong = new LongWritable();
  private final IntWritable resultInt = new IntWritable();

  public DoubleWritable evaluate(DoubleWritable n) {
    if (n == null) {
      return null;
    }

    resultDouble.set(Math.abs(n.get()));

    return resultDouble;
  }

  public LongWritable evaluate(LongWritable n) {
    if (n == null) {
      return null;
    }

    resultLong.set(Math.abs(n.get()));

    return resultLong;
  }

  public IntWritable evaluate(IntWritable n) {
    if (n == null) {
      return null;
    }

    resultInt.set(Math.abs(n.get()));

    return resultInt;
  }
}