/**
* 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.serde2.objectinspector;
import java.util.HashMap;
import java.util.Map;
/**
* StandardMapObjectInspector works on map data that is stored as a Java Map
* object. Note: the key object of the map must support equals and hashCode by
* itself.
*
* We also plan to have a GeneralMapObjectInspector which can work on map with
* key objects that does not support equals and hashCode. That will require us
* to store InspectableObject as the key, which will have overridden equals and
* hashCode methods.
*
* Always use the ObjectInspectorFactory to create new ObjectInspector objects,
* instead of directly creating an instance of this class.
*/
public class StandardMapObjectInspector implements SettableMapObjectInspector {
private ObjectInspector mapKeyObjectInspector;
private ObjectInspector mapValueObjectInspector;
protected StandardMapObjectInspector() {
super();
}
/**
* Call ObjectInspectorFactory.getStandardMapObjectInspector instead.
*/
protected StandardMapObjectInspector(ObjectInspector mapKeyObjectInspector,
ObjectInspector mapValueObjectInspector) {
this.mapKeyObjectInspector = mapKeyObjectInspector;
this.mapValueObjectInspector = mapValueObjectInspector;
}
// without data
public ObjectInspector getMapKeyObjectInspector() {
return mapKeyObjectInspector;
}
public ObjectInspector getMapValueObjectInspector() {
return mapValueObjectInspector;
}
// with data
// TODO: Now we assume the key Object supports hashCode and equals functions.
public Object getMapValueElement(Object data, Object key) {
if (data == null || key == null) {
return null;
}
Map<?, ?> map = (Map<?, ?>) data;
return map.get(key);
}
public int getMapSize(Object data) {
if (data == null) {
return -1;
}
Map<?, ?> map = (Map<?, ?>) data;
return map.size();
}
public Map<?, ?> getMap(Object data) {
if (data == null) {
return null;
}
Map<?, ?> map = (Map<?, ?>) data;
return map;
}
public final Category getCategory() {
return Category.MAP;
}
public String getTypeName() {
return org.apache.hadoop.hive.serde.serdeConstants.MAP_TYPE_NAME + "<"
+ mapKeyObjectInspector.getTypeName() + ","
+ mapValueObjectInspector.getTypeName() + ">";
}
// /////////////////////////////
// SettableMapObjectInspector
@Override
public Object create() {
Map<Object, Object> m = new HashMap<Object, Object>();
return m;
}
@Override
public Object clear(Object map) {
Map<Object, Object> m = (HashMap<Object, Object>) map;
m.clear();
return m;
}
@Override
public Object put(Object map, Object key, Object value) {
Map<Object, Object> m = (HashMap<Object, Object>) map;
m.put(key, value);
return m;
}
@Override
public Object remove(Object map, Object key) {
Map<Object, Object> m = (HashMap<Object, Object>) map;
m.remove(key);
return m;
}
}