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/tags/release-0.1-rc2/hive/external/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFConcat.java

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Java | 53 lines | 25 code | 7 blank | 21 comment | 3 complexity | 1b565f8ca909545624a5f2e22e2b26ed 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.ql.udf;
20
21import org.apache.hadoop.hive.ql.exec.Description;
22import org.apache.hadoop.hive.ql.exec.UDF;
23import org.apache.hadoop.io.Text;
24
25/**
26 * UDFConcat.
27 *
28 */
29@Description(name = "concat",
30    value = "_FUNC_(str1, str2, ... strN) - returns the concatenation of str1, str2, ... strN",
31    extended = "Returns NULL if any argument is NULL.\n"
32    + "Example:\n"
33    + "  > SELECT _FUNC_('abc', 'def') FROM src LIMIT 1;\n"
34    + "  'abcdef'")
35public class UDFConcat extends UDF {
36
37  public UDFConcat() {
38  }
39
40  private Text text = new Text();
41
42  public Text evaluate(Text... args) {
43    text.clear();
44    for (Text arg : args) {
45      if (arg == null) {
46        return null;
47      }
48      text.append(arg.getBytes(), 0, arg.getLength());
49    }
50    return text;
51  }
52
53}