/**
* 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;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Text;
/**
* UDFConcat.
*
*/
@Description(name = "concat",
value = "_FUNC_(str1, str2, ... strN) - returns the concatenation of str1, str2, ... strN or "+
"_FUNC_(bin1, bin2, ... binN) - returns the concatenation of bytes in binary data " +
" bin1, bin2, ... binN",
extended = "Returns NULL if any argument is NULL.\n"
+ "Example:\n"
+ " > SELECT _FUNC_('abc', 'def') FROM src LIMIT 1;\n"
+ " 'abcdef'")
public class UDFConcat extends UDF {
public UDFConcat() {
}
private final Text text = new Text();
public Text evaluate(Text... args) {
text.clear();
for (Text arg : args) {
if (arg == null) {
return null;
}
text.append(arg.getBytes(), 0, arg.getLength());
}
return text;
}
public BytesWritable evaluate(BytesWritable... bw){
int len = 0;
for(BytesWritable bytes : bw){
if (bytes == null){
return null;
}
len += bytes.getLength();
}
byte[] out = new byte[len];
int curLen = 0;
// Need to iterate twice since BytesWritable doesn't support append.
for (BytesWritable bytes : bw){
System.arraycopy(bytes.getBytes(), 0, out, curLen, bytes.getLength());
curLen += bytes.getLength();
}
return new BytesWritable(out);
}
}