/**
* 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.UDF;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
import org.apache.hadoop.hive.serde2.io.HiveDecimalWritable;
/**
* This class can be used for math based UDFs that only have an evaluate method for {@code doubles}. By extending from
* this class these UDFs will automatically support decimals as well.
*/
public abstract class UDFMath extends UDF {
private final DoubleWritable doubleWritable = new DoubleWritable();
/**
* For subclass to implement.
*/
protected abstract DoubleWritable doEvaluate(DoubleWritable a);
/**
* Returns {@code null} if the passed in value is {@code} and passes on to {@link #doEvaluate(DoubleWritable)} if not.
*/
public final DoubleWritable evaluate(DoubleWritable a) {
if (a == null) {
return null;
}
return doEvaluate(a);
}
/**
* Convert HiveDecimal to a double and call evaluate() on it.
*/
public final DoubleWritable evaluate(HiveDecimalWritable writable) {
if (writable == null) {
return null;
}
double d = writable.doubleValue();
doubleWritable.set(d);
return doEvaluate(doubleWritable);
}
}