/tags/release-0.0.0-rc0/hive/external/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFHash.java
Java | 64 lines | 33 code | 9 blank | 22 comment | 1 complexity | ef4ce7d7c309c63e4d9b13bb3c112286 MD5 | raw file
Possible License(s): Apache-2.0, BSD-3-Clause, JSON, CPL-1.0
- /**
- * 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.generic;
- import org.apache.commons.lang.StringUtils;
- 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.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;
- /**
- * GenericUDF Class for computing hash values.
- */
- @Description(name = "hash", value = "_FUNC_(a1, a2, ...) - Returns a hash value of the arguments")
- public class GenericUDFHash extends GenericUDF {
- private ObjectInspector[] argumentOIs;
- @Override
- public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentTypeException {
- argumentOIs = arguments;
- return PrimitiveObjectInspectorFactory.writableIntObjectInspector;
- }
- private IntWritable result = new IntWritable();
- @Override
- public Object evaluate(DeferredObject[] arguments) throws HiveException {
- // See
- // http://java.sun.com/j2se/1.5.0/docs/api/java/util/List.html#hashCode()
- int r = 0;
- for (int i = 0; i < arguments.length; i++) {
- r = r * 31
- + ObjectInspectorUtils.hashCode(arguments[i].get(), argumentOIs[i]);
- }
- result.set(r);
- return result;
- }
- @Override
- public String getDisplayString(String[] children) {
- return "hash(" + StringUtils.join(children, ',') + ")";
- }
- }