private String getJSONunitActivity(AggregateDB agg_db, String unit) { // e.g.: activityIds: { ex: ["1"], qz: ["2"] } String output = " activityIds: { "; HashMap<String, ArrayList<String>> resActList = agg_db.getResourceActivity(unit); // each element of actList contains {key:resource_id, value:activityList of that resource} for (String res : resActList.keySet()) { output += res + ": [" + getActString(resActList.get(res)) + "], "; } if (resActList.isEmpty() == false) output = output.substring(0, output.length() - 2); // ignoring the last comma output += " }"; return output; }