org.apache.hadoop.hive.ql.udf.generic.GenericUDFMurmurHash Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.hive.ql.udf.generic;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.serde2.ByteStream;
import org.apache.hadoop.hive.serde2.SerDeException;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.IntWritable;
import org.apache.hive.common.util.Murmur3;
/**
* GenericUDF Class for computing murmurhash values.
*/
@Description(name = "hash", value = "_FUNC_(a1, a2, ...) - Returns a hash value of the arguments")
public class GenericUDFMurmurHash extends GenericUDF {
private transient ObjectInspector[] argumentOIs;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentTypeException {
argumentOIs = arguments;
return PrimitiveObjectInspectorFactory.writableIntObjectInspector;
}
private final IntWritable result = new IntWritable();
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
Object[] fieldValues = new Object[arguments.length];
for(int i = 0; i < arguments.length; i++) {
fieldValues[i] = arguments[i].get();
}
int r = ObjectInspectorUtils.getBucketHashCode(fieldValues, argumentOIs);
result.set(r);
return result;
}
@Override
public String getDisplayString(String[] children) {
return getStandardDisplayString("hash", children, ",");
}
}