Can the XPage JSON library automatically convert a Java Bean to a JSON representation?

Question

I want to use the com.ibm.commons.util.io.json.* library which comes with the XPages runtime to serialise a Java Bean into JSON.

The question is can it do it automatically by just passing it the object - like you can with the Google library - http://code.google.com/p/google-gson/ or do you need to construct the JSON manually by which I mean passing the individual properties to construct the JSON.

Having trouble locating the documentation for this library, though I have seen some examples:

http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=JSON%20and%20REST%20Samples

http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Sending_requests_in_Java_dds10

Ideally we dont want to use a 3rd party library, even though it works great, because we need to modify the java security properties file which in turn gets wiped if the server gets upgraded.

Answer 1

The com.ibm.commons.util.io.json library is a genric library for converting JSON representations to Java objects, back and forth. By generic, I mean that it uses a factory to both browse and update the Java objects (see: JsonFactory). By implementing such a factory, and implementing the getter/setters for all the properties, one can serialize/deserialize any kind of objects. The JSON library is equiped with a set of predefined factories:

• JsonJavaFactory, that maps JSON Objects to Java Maps (with a extended version that uses a JsonJavaObject wrapper which is more convenient)
• JsonJavaScriptFactory, that maps JSON objects to actual JavaScript objects (see: ObjectObject) and Java values (String, Integer...) to JavaScript values (FBSString, FBSNumber...). These objects can be directly used by the server side JS engine.

We don't have a factory for JavaBeans per say, but implementing such a factory should not be a big deal.

Answer 2

The ibm commons library for json works by constructing an object, then adding json properties to the object. It can not auto-serialize an object, and works really only with primitive data types.

I've attached some SSJS code to illustrate how to work with the class. It assumes recordMap is a java map instance with some beans in it, and each bean has 5 fields named fieldName1 through fieldName5. The code iterates through each bean in the map, retrieves the 5 fields, convert the values to JSON, then pushes them into array. Finally the array is put inside another json object that includes the count, and the array itself.

var jsonObjArr = [];

var itr:java.util.Iterator = recordMap.keySet().iterator();
while (itr.hasNext()) {

   var record = recordMap.get(itr.next());
   var jsonObj:com.ibm.commons.util.io.json.JsonJavaObject = 
          new com.ibm.commons.util.io.json.JsonJavaObject();

    jsonObj.putJsonProperty("fieldName1", record.getFieldName1());
    jsonObj.putJsonProperty("fieldName2", record.getFieldName2());
    jsonObj.putJsonProperty("fieldName3", record.getFieldName3());
    jsonObj.putJsonProperty("fieldName4", record.getFieldName4());
    jsonObj.putJsonProperty("fieldName5", record.getFieldName5());
    jsonObj.putJsonProperty("fieldName6", record.getFieldName6());

    jsonObjArr.push(com.ibm.commons.util.io.json.JsonGenerator
        .toJson(com.ibm.commons.util.io.json.JsonJavaFactory.instanceEx, empr));

};

var jsonString = "{" +
    "count:" + @Text(jsonObjArr.length) + "," +
    "employees:" + "[" + jsonObjArr.join(",") + "]" + 
"}";

return jsonString;

Hope this helps..