/**
* 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.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.exec.description;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
/**
* Generic UDF for string function <code>LOCATE(substr, str)</code>, <code>LOCATE(substr, str, start)</code>.
* This mimcs the function from MySQL
* http://dev.mysql.com/doc/refman/5.1/en/string-functions.html#function_locate
* <pre>
* usage:
* LOCATE(substr, str)
* LOCATE(substr, str, start)
* </pre><p>
*/
@description(
name = "locate",
value = "_FUNC_(substr, str[, pos]) - Returns the position of the first " +
"occurance of substr in str after position pos",
extended = "Example:\n" +
" > SELECT _FUNC_('bar', 'foobarbar', 5) FROM src LIMIT 1;\n" +
" 7"
)
public class GenericUDFLocate extends GenericUDF{
ObjectInspectorConverters.Converter[] converters;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments)
throws UDFArgumentException {
if (arguments.length != 2 && arguments.length != 3) {
throw new UDFArgumentLengthException(
"The function LOCATE accepts exactly 2 or 3 arguments.");
}
for(int i = 0; i < arguments.length; i++) {
Category category = arguments[i].getCategory();
if(category != Category.PRIMITIVE) {
throw new UDFArgumentTypeException(i,
"The " + GenericUDFUtils.getOrdinal(i + 1) + " argument of function LOCATE is expected to a "
+ Category.PRIMITIVE.toString().toLowerCase()
+ " type, but " + category.toString().toLowerCase() + " is found");
}
}
converters = new ObjectInspectorConverters.Converter[arguments.length];
for(int i = 0; i < arguments.length; i++) {
if(i == 0 || i == 1) {
converters[i] = ObjectInspectorConverters.getConverter(arguments[i],
PrimitiveObjectInspectorFactory.writableStringObjectInspector);
} else if(i == 2) {
converters[i] = ObjectInspectorConverters.getConverter(arguments[i],
PrimitiveObjectInspectorFactory.writableIntObjectInspector);
}
}
return PrimitiveObjectInspectorFactory.writableIntObjectInspector;
}
IntWritable intWritable = new IntWritable(0);
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
if(arguments[0].get() == null || arguments[1].get() == null)
return null;
Text subtext = (Text) converters[0].convert(arguments[0].get());
Text text = (Text) converters[1].convert(arguments[1].get());
int start = 1;
if(arguments.length == 3) {
IntWritable startWritable = (IntWritable)converters[2].convert(arguments[2].get());
if(startWritable == null) {
intWritable.set(0);
return intWritable;
}
start = startWritable.get();
}
intWritable.set(GenericUDFUtils.findText(text, subtext, start - 1) + 1);
return intWritable;
}
@Override
public String getDisplayString(String[] children) {
assert(children.length == 2 || children.length == 3);
return "locate(" + children[0] + children[1]
+ (children.length == 3 ? children[2] : "") + ")";
}
}