/tags/release-0.0.0-rc0/hive/external/serde/src/java/org/apache/hadoop/hive/serde2/objectinspector/StandardMapObjectInspector.java
Java | 125 lines | 70 code | 17 blank | 38 comment | 8 complexity | 2b7a59cece1df82d5877abf046b4142e 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.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 {
- ObjectInspector mapKeyObjectInspector;
- ObjectInspector mapValueObjectInspector;
- /**
- * 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.Constants.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;
- }
- }