/**
* 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.commons.lang.StringUtils;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
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.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.IntWritable;
/**
* GenericUDFField.
*
*/
@Description(name = "field", value = "_FUNC_(str, str1, str2, ...) - "
+ "returns the index of str in the str1,str2,... list or 0 if not found", extended = "All primitive types are supported, arguments are compared using str.equals(x)."
+ " If str is NULL, the return value is 0.")
public class GenericUDFField extends GenericUDF {
private transient ObjectInspector[] argumentOIs;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments)
throws UDFArgumentException {
if (arguments.length < 2) {
throw new UDFArgumentException(
"The function FIELD(str, str1, str2, ...) needs at least two arguments.");
}
argumentOIs = 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 FIELD is expected to a "
+ Category.PRIMITIVE.toString().toLowerCase() + " type, but "
+ category.toString().toLowerCase() + " is found");
}
}
return PrimitiveObjectInspectorFactory.writableIntObjectInspector;
}
private final IntWritable r = new IntWritable();
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
if (arguments[0].get() == null) {
r.set(0);
return r;
}
for (int i = 1; i < arguments.length; i++) {
if (arguments[i].get() == null) {
continue;
}
if (ObjectInspectorUtils.compare(arguments[0].get(), argumentOIs[0],
arguments[i].get(), argumentOIs[i]) == 0) {
r.set(i);
return r;
}
}
r.set(0);
return r;
}
@Override
public String getDisplayString(String[] children) {
assert (children.length >= 2);
final StringBuilder sb = new StringBuilder();
sb.append("field(");
sb.append(StringUtils.join(children, ", "));
sb.append(")");
return sb.toString();
}
}