org.openx.data.jsonserde.objectinspector.JSONObjectMapAdapter Maven / Gradle / Ivy
/*======================================================================*
* Copyright (c) 2011, OpenX Technologies, Inc. All rights reserved. *
* *
* Licensed under the New BSD License (the "License"); you may not use *
* this file except in compliance with the License. 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. See accompanying LICENSE file. *
*======================================================================*/
package org.openx.data.jsonserde.objectinspector;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.openx.data.jsonserde.json.JSONException;
import org.openx.data.jsonserde.json.JSONObject;
/**
* JSONObject is technically different from a map, since a json object
* has string keys and values can be of any kind, while hive could
* define a column as map<string,string>. This consistency is left
* to the user to satisfy.
*
* Since we want to present a map, and we don't want to extract keys
* and values every time, we keep a cache
*
* @author rcongiu
*/
/* TODO: having an initialize() that copies everything into a map is expensive
and won't work well for large maps. Good enough for now since
we seldom - if ever - use maps. */
public class JSONObjectMapAdapter implements Map {
HashMap cache;
JSONObject jsonObject;
public JSONObjectMapAdapter(JSONObject obj) {
jsonObject = obj;
initialize();
}
public JSONObjectMapAdapter() {
}
public JSONObject getJSONObject() {
return jsonObject;
}
public void setJSONObject(JSONObject jsonObject) {
this.jsonObject = jsonObject;
initialize();
}
@Override
public int size() {
return jsonObject.length();
}
@Override
public boolean isEmpty() {
return cache.isEmpty();
}
protected final void initialize() {
if(cache==null) cache = new HashMap();
for(Iterator i = jsonObject.keys(); i.hasNext(); ) {
String o = i.next();
try {
cache.put(o, safeGet(o));
} catch (JSONException ex) {
// if key does not exist - should not happen
throw new RuntimeException("Non existent key - should never happen!");
}
}
}
/**
* sanitize all the JSONObject.NULL converting them to nulls.
* @param s
* @return
* @throws JSONException
*/
private Object safeGet(String s) throws JSONException {
if(s == null) return null;
Object obj = jsonObject.get(s);
if(JSONObject.NULL.equals(obj)) {
return null;
} else {
return obj;
}
}
@Override
public boolean containsKey(Object key) {
return cache.containsKey(key);
}
@Override
public boolean containsValue(Object value) {
return cache.containsValue(value);
}
@Override
public Object get(Object key) {
return cache.get(key);
}
@Override
public Object put(Object key, Object value) {
return cache.put(key,value);
}
@Override
public Object remove(Object key) {
return cache.remove(key);
}
@Override
public void putAll(Map m) {
cache.putAll(m);
}
@Override
public void clear() {
cache.clear();
}
@Override
public Set keySet() {
return cache.keySet();
}
@Override
public Collection values() {
return cache.values();
}
@Override
public Set entrySet() {
return cache.entrySet();
}
public Map getMap() {
return cache;
}
}