Helper class to decode and encode objects to and from Json (Ext GWT)
/*
* Ext GWT - Ext for GWT
* Copyright(c) 2007-2009, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
//package com.extjs.gxt.ui.client.js;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import com.extjs.gxt.ui.client.core.FastMap;
import com.extjs.gxt.ui.client.data.ModelData;
import com.google.gwt.json.client.JSONArray;
import com.google.gwt.json.client.JSONBoolean;
import com.google.gwt.json.client.JSONNull;
import com.google.gwt.json.client.JSONObject;
import com.google.gwt.json.client.JSONParser;
import com.google.gwt.json.client.JSONString;
import com.google.gwt.json.client.JSONValue;
/**
* Helper class to decode and encode objects to and from Json. Converter handles
* simple data types (strings, numbers, booleans) and lists and maps.
*/
public class JsonConverter {
/**
* Decodes a Json string into a map.
*
* @param jsonString the Json string
* @return the map
*/
public static Map<String, Object> decode(String jsonString) {
JSONValue v = JSONParser.parse(jsonString);
if (v.isObject() != null) {
return decode(v.isObject());
} else {
return null;
}
}
/**
* Decodes a JSONObject to a map.
*
* @param jso the JSONObject
* @return the map
*/
public static Map<String, Object> decode(JSONObject jso) {
Map<String, Object> map = new FastMap<Object>();
for (String key : jso.keySet()) {
JSONValue j = jso.get(key);
if (j.isObject() != null) {
map.put(key, decode(j.isObject()));
} else if (j.isArray() != null) {
map.put(key, decodeToList(j.isArray()));
} else if (j.isBoolean() != null) {
map.put(key, j.isBoolean().booleanValue());
} else if (j.isString() != null) {
map.put(key, decodeValue(j.isString().stringValue()));
}
}
return map;
}
/**
* Encodes a map into a JSONObject.
*
* @param map the map
* @return the JSONObject
*/
public static JSONObject encode(Map<String, Object> map) {
return encodeMap((Map<String, Object>) map);
}
/**
* Encodes a model data instance into a JSONObject.
*
* @param model the model data object
* @return the JSONObject
*/
public static JSONObject encode(ModelData model) {
return encodeMap(((ModelData) model).getProperties());
}
protected static Object decodeValue(String value) {
try {
if (value == null || value.length() < 3) {
return null;
}
String type = value.substring(0, 2);
String val = value.substring(2);
if (type.equals("d:")) {
long time = Long.parseLong(val);
return new Date(time);
} else if (type.equals("i:")) {
return Integer.decode(val);
} else if (type.equals("f:")) {
return new Float(val);
}
return val;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
protected static List<Object> decodeToList(JSONArray array) {
List<Object> list = new ArrayList<Object>();
for (int i = 0; i < array.size(); i++) {
JSONValue v = array.get(i);
if (v.isObject() != null) {
list.add(decode(v.isObject()));
} else if (v.isArray() != null) {
list.add(decodeToList(v.isArray()));
} else if (v.isNull() != null) {
list.add(null);
} else if (v.isNumber() != null) {
list.add(v.isNumber().doubleValue());
} else if (v.isBoolean() != null) {
list.add(v.isBoolean().booleanValue());
} else if (v.isString() != null) {
list.add(decodeValue(v.isString().stringValue()));
}
}
return list;
}
protected static String encodeValue(Object value) {
if (value instanceof Date) {
return "d:" + ((Date) value).getTime();
} else if (value instanceof Integer) {
return "i:" + value;
} else if (value instanceof Float) {
return "f:" + value;
}
return "s:" + value.toString();
}
@SuppressWarnings("unchecked")
protected static JSONObject encodeMap(Map<String, Object> data) {
JSONObject jsobj = new JSONObject();
for (String key : data.keySet()) {
Object val = data.get(key);
if (val instanceof String) {
jsobj.put(key, new JSONString(encodeValue(val)));
} else if (val instanceof Date) {
jsobj.put(key, new JSONString(encodeValue(val)));
} else if (val instanceof Number) {
jsobj.put(key, new JSONString(encodeValue(val)));
} else if (val instanceof Boolean) {
jsobj.put(key, JSONBoolean.getInstance((Boolean) val));
} else if (val == null) {
jsobj.put(key, JSONNull.getInstance());
} else if (val instanceof Map) {
jsobj.put(key, encodeMap((Map<String, Object>) val));
} else if (val instanceof List) {
jsobj.put(key, encodeList((List<Object>) val));
} else if (val instanceof ModelData) {
jsobj.put(key, encodeMap(((ModelData) val).getProperties()));
}
}
return jsobj;
}
@SuppressWarnings("unchecked")
protected static JSONArray encodeList(List<Object> data) {
JSONArray jsona = new JSONArray();
for (int i = 0; i < data.size(); i++) {
Object val = data.get(i);
if (val instanceof ModelData) {
jsona.set(i, encodeMap(((ModelData) val).getProperties()));
} else if (val instanceof Map) {
jsona.set(i, encodeMap((Map<String, Object>) val));
} else if (val instanceof List) {
jsona.set(i, encodeList((List<Object>) val));
} else if (val instanceof String) {
jsona.set(i, new JSONString(encodeValue(val)));
} else if (val instanceof Number) {
jsona.set(i, new JSONString(encodeValue(val)));
} else if (val instanceof Boolean) {
jsona.set(i, JSONBoolean.getInstance((Boolean) val));
} else if (val == null) {
jsona.set(i, JSONNull.getInstance());
} else if (val instanceof Date) {
jsona.set(i, new JSONString(encodeValue(val)));
}
}
return jsona;
}
}
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