org.apache.hadoop.hive.ql.udf.UDFLog10 Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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* 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.vector.VectorizedExpressions;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncLog10DoubleToDouble;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncLog10LongToDouble;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
/**
* UDFLog10.
*/
@Description(name = "log10",
value = "_FUNC_(x) - Returns the logarithm of x with base 10",
extended = "Example:\n"
+ " > SELECT _FUNC_(10) FROM src LIMIT 1;\n"
+ " 1")
@VectorizedExpressions({FuncLog10LongToDouble.class, FuncLog10DoubleToDouble.class})
public class UDFLog10 extends UDFMath {
private final DoubleWritable result = new DoubleWritable();
/**
* Returns the logarithm of "a" with base 10.
*/
@Override
protected DoubleWritable doEvaluate(DoubleWritable a) {
if (a.get() <= 0.0) {
return null;
} else {
result.set(Math.log10(a.get()));
return result;
}
}
}