/tags/release-0.0.0-rc0/hive/external/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFLocate.java
Java | 115 lines | 75 code | 11 blank | 29 comment | 27 complexity | 62416e83df9a9cb61d48de404c8d48d9 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.hadoop.hive.ql.exec.Description;
- 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.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 {
- private 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;
- }
- private 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] : "") + ")";
- }
- }