package brickhouse.udf.collect;
/**
* Copyright 2012 Klout, Inc
*
* Licensed 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.
*
**/
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.MapObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.log4j.Logger;
import java.util.Map;
/**
* Workaround for the Hive bug
* https://issues.apache.org/jira/browse/HIVE-1955
* <p/>
* FAILED: Error in semantic analysis: Line 4:3 Non-constant expressions for array indexes not supported key
* <p/>
* <p/>
* Use instead of [ ] syntax,
*/
public class MapIndexUDF extends GenericUDF {
private static final Logger LOG = Logger.getLogger(MapIndexUDF.class);
private PrimitiveObjectInspector keyInspector;
private MapObjectInspector mapInspector;
private PrimitiveObjectInspector mapKeyInspector;
private CreateWithPrimitive createKey;
@Override
public Object evaluate(DeferredObject[] args) throws HiveException {
Map<?, ?> map = mapInspector.getMap(args[0].get());
Object key = keyInspector.getPrimitiveJavaObject(args[1].get());
if (key == null) {
return map.get(null);
}
if (createKey != null) {
return map.get(createKey.create(key));
}
for (Map.Entry<?, ?> e : map.entrySet()) {
if (key.equals(mapKeyInspector.getPrimitiveJavaObject(e.getKey()))) {
return e.getValue();
}
}
return null;
}
@Override
public String getDisplayString(String[] args) {
return "map_index( " + args[0] + " , " + args[1] + ")";
}
@Override
public ObjectInspector initialize(ObjectInspector[] args)
throws UDFArgumentException {
if (args.length != 2) {
throw new UDFArgumentException("Usage : map_index( map, key)");
}
if (args[0].getCategory() != Category.MAP
|| args[1].getCategory() != Category.PRIMITIVE) {
throw new UDFArgumentException("Usage : map_index( map, key) - First argument must be a map, second must be a matching key");
}
mapInspector = (MapObjectInspector) args[0];
mapKeyInspector = (PrimitiveObjectInspector) mapInspector.getMapKeyObjectInspector();
keyInspector = (PrimitiveObjectInspector) args[1];
if (mapKeyInspector.getPrimitiveCategory() != keyInspector.getPrimitiveCategory()) {
throw new UDFArgumentException("Usage : map_index( map, key) - First argument must be a map, second must be a matching key");
}
createKey = CreateWithPrimitive.getCreate(mapKeyInspector);
return mapInspector.getMapValueObjectInspector();
}
}