/**
* 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.metadata.HiveException;
import org.apache.hadoop.hive.serde.Constants;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.BooleanObjectInspector;
/**
* IF(expr1,expr2,expr3) <br>
* If expr1 is TRUE (expr1 <> 0 and expr1 <> NULL) then IF() returns expr2;
* otherwise it returns expr3. IF() returns a numeric or string value, depending
* on the context in which it is used.
*/
public class GenericUDFIf extends GenericUDF {
private ObjectInspector[] argumentOIs;
private GenericUDFUtils.ReturnObjectInspectorResolver returnOIResolver;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
argumentOIs = arguments;
returnOIResolver = new GenericUDFUtils.ReturnObjectInspectorResolver(true);
if (arguments.length != 3) {
throw new UDFArgumentLengthException(
"The function IF(expr1,expr2,expr3) accepts exactly 3 arguments.");
}
boolean conditionTypeIsOk = (arguments[0].getCategory() == ObjectInspector.Category.PRIMITIVE);
if (conditionTypeIsOk) {
PrimitiveObjectInspector poi = ((PrimitiveObjectInspector) arguments[0]);
conditionTypeIsOk = (poi.getPrimitiveCategory() == PrimitiveObjectInspector.PrimitiveCategory.BOOLEAN
|| poi.getPrimitiveCategory() == PrimitiveObjectInspector.PrimitiveCategory.VOID);
}
if (!conditionTypeIsOk) {
throw new UDFArgumentTypeException(0,
"The first argument of function IF should be \""
+ Constants.BOOLEAN_TYPE_NAME + "\", but \""
+ arguments[0].getTypeName() + "\" is found");
}
if (!(returnOIResolver.update(arguments[1]) && returnOIResolver
.update(arguments[2]))) {
throw new UDFArgumentTypeException(2,
"The second and the third arguments of function IF should have the same type, "
+ "but they are different: \"" + arguments[1].getTypeName()
+ "\" and \"" + arguments[2].getTypeName() + "\"");
}
return returnOIResolver.get();
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
Object condition = arguments[0].get();
if (condition != null
&& ((BooleanObjectInspector) argumentOIs[0]).get(condition)) {
return returnOIResolver.convertIfNecessary(arguments[1].get(),
argumentOIs[1]);
} else {
return returnOIResolver.convertIfNecessary(arguments[2].get(),
argumentOIs[2]);
}
}
@Override
public String getDisplayString(String[] children) {
assert (children.length == 3);
StringBuilder sb = new StringBuilder();
sb.append("if(");
sb.append(children[0]).append(", ");
sb.append(children[1]).append(", ");
sb.append(children[2]).append(")");
return sb.toString();
}
}