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/tags/release-0.2.0-rc0/hive/external/contrib/src/java/org/apache/hadoop/hive/contrib/udf/UDFRowSequence.java

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Java | 46 lines | 19 code | 6 blank | 21 comment | 0 complexity | 93107655a633280ab66eadfe894a0b4e MD5 | raw file
 1/**
 2 * Licensed to the Apache Software Foundation (ASF) under one
 3 * or more contributor license agreements.  See the NOTICE file
 4 * distributed with this work for additional information
 5 * regarding copyright ownership.  The ASF licenses this file
 6 * to you under the Apache License, Version 2.0 (the
 7 * "License"); you may not use this file except in compliance
 8 * with the License.  You may obtain a copy of the License at
 9 *
10 *     http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19package org.apache.hadoop.hive.contrib.udf;
20
21import org.apache.hadoop.hive.ql.exec.Description;
22import org.apache.hadoop.hive.ql.exec.UDF;
23import org.apache.hadoop.hive.ql.udf.UDFType;
24import org.apache.hadoop.io.LongWritable;
25
26/**
27 * UDFRowSequence.
28 */
29@Description(name = "row_sequence",
30    value = "_FUNC_() - Returns a generated row sequence number starting from 1")
31@UDFType(deterministic = false, stateful = true)
32public class UDFRowSequence extends UDF
33{
34  private LongWritable result = new LongWritable();
35
36  public UDFRowSequence() {
37    result.set(0);
38  }
39
40  public LongWritable evaluate() {
41    result.set(result.get() + 1);
42    return result;
43  }
44}
45
46// End UDFRowSequence.java