Implement opt/get methods for accumulated values #551

void someFunction() {
  JSONObject jo = XML.toJSONObject(someXmlSource);
  JSONObject student = jo.getJSONObject("Student");
  if ( student.optJSONArray("subjects") ==null ) {
      processSubject(student.optJSONObject("subjects"));
  } else {
      processSubjects(student.optJSONArray("subjects"));
  }
}

void processSubjects(JSONArray subjects) {
  if (subjects == null || subjects.length() == 0) return;
  for(int i=0; i<subjects.length; i++) {
    processSubject(subjects.getJSONObject(i));
  }
}

void processSubject(JSONObject subject) {
  // some implementation
}

// In JSONObject

/**
* Always returns a JSONArray, If the key doesn't exist or the value is `null`, the array will be empty.
* If the key holds a non-array/non-collection value, then it is placed in a JSONArray
* before returning.
* If the value is a JSONArray, then a copy is returned.
* If the value is directly convertible to a JSONArray (i.e. a JAVA Array or Collection), then it is
* converted to a JSONArray.
* @param key The key in the JSONObject to fetch
* @returns a JSONArray regardless of the value of the key.
*/
public JSONArray optAccumulated(String key) {
  Object o = opt(key);
  if (JSONObject.NULL.equals(o)) {
    return new JSONArray();
  }
  if (o instanceof JSONArray) {
    return new JSONArray(((JSONArray)o).myArrayList); // maybe create a copy constructor and/or extend putAll
  }
  if (o instanceof Collection || o.getClass().isArray()) {
    return new JSONArray(o);
  }
  JSONArray ret = new JSONArray();
  ret.put(o);
  return ret;
}


/**
* Always returns a JSONArray, If the key value is `null`, the array will be empty.
* If the key holds a non-array/non-collection value, then it is placed in a JSONArray
* before returning.
* If the value is a JSONArray, then a copy is returned.
* If the value is directly convertible to a JSONArray (i.e. a JAVA Array or Collection), then it is
* converted to a JSONArray.
* @param key The key in the JSONObject to fetch
* @returns a JSONArray regardless of the value of the key.
* @throws JSONException Thrown when the key does not exist
*/
public JSONArray getAccumulated(String key) throws JSONException {
  Object o = get(key);
  if (JSONObject.NULL.equals(o)) {
    return new JSONArray();
  }
  if (o instanceof JSONArray) {
    return new JSONArray(((JSONArray)o).myArrayList); // maybe create a copy constructor and/or extend putAll
  }
  if (o instanceof Collection || o.getClass().isArray()) {
    return new JSONArray(o);
  }
  JSONArray ret = new JSONArray();
  ret.put(o);
  return ret;
}