Qfyilyi

I am programming Java after long time and i am just new to Json.
I found a strange issue but not sure if I am not understanding it correctly.

This is part of the XML file i am reading:

<Events>

      <event comment="topota1" file="test1.mp4" id="0" time="1000"/>

      <event comment="topota2" file="test2.mp4" id="1" time="2000"/>

      <event comment="topota3" file="test3.mp4" id="2" time="3000"/>

      <event comment="topota4" file="test4.mp4" id="3" time="4000"/>

</Events>

I did a Json structure to manage some events information:

package miCMS;

{***}

import org.json.JSONArray;

import org.json.JSONObject;

{***}

JSONObject Event = new JSONObject();

JSONArray EventArr = new JSONArray();

{***}

public class miPlayer{

{***}



public void addEvent(int Id, int Time, String File, String Comment) {

      try {

          Event.put("Id", Id);

          Event.put("Time", Time);

          Event.put("File", File);

          Event.put("Comment", Comment);

          EventArr.put(Event);

      }catch ( Exception e ) {e.printStackTrace();}

}

In another Java file I am reading the XML file and asigning to my Json Array:

package miCMS;

{***}

public class miXMLParser{



  public static miCMS.miPlayer ReadFromXML(String Path){

       try {



          DOMParser parser = new DOMParser();

          parser.parse(Path);

          Document doc = parser.getDocument();



///////////////////////////////////EVENTOS!!!!!!!!!!!!!!!!!!!!!!!!!!!!

          NodeList childNodesEvent = doc.getElementsByTagName("event"); 



          for (int x = 0; x < childNodesEvent.getLength(); x++ ) {

              Node NodeEvent = childNodesEvent.item(x);



              player.addEvent(x, 1000, "", "");



              NamedNodeMap attrsEvent = NodeEvent.getAttributes();

              for (int y = 0; y < attrsEvent.getLength(); y++ ) {

                  Node attrEvent = attrsEvent.item(y);

                  String AttribName = attrEvent.getNodeName();



                  switch (AttribName) {

                      case "id":  

                          player.EventArr.getJSONObject(x).put("Id",Integer.parseInt(attrEvent.getNodeValue()));

                          System.out.println(">X:" + x + " // Id:" + player.EventArr.getJSONObject(x).getInt("Id"));

                          break;

                      case "time":  

                          player.EventArr.getJSONObject(x).put("Time",Integer.parseInt(attrEvent.getNodeValue()));

                          break;

                      case "file":  

                          player.EventArr.getJSONObject(x).put("File",attrEvent.getNodeValue());

                          break;

                      case "comment":  

                          player.EventArr.getJSONObject(x).put("Comment",attrEvent.getNodeValue());

                          break;

                  }           

              }

          }



          System.out.println("DESPUES DEL FOR");

          System.out.println(">>X:0" + " // Id:" + player.EventArr.getJSONObject(0).getInt("Id"));

          System.out.println(">>X:1" + " // Id:" + player.EventArr.getJSONObject(1).getInt("Id"));

          System.out.println(">>X:2" + " // Id:" + player.EventArr.getJSONObject(2).getInt("Id"));

          System.out.println(">>X:3" + " // Id:" + player.EventArr.getJSONObject(3).getInt("Id"));



      }catch (Exception e) {

          e.printStackTrace();

      }



      return player;

  }

for some reason, all the elements in my JSON array is storing the information coming form the last element in my XML file.
I forced some printlines to see what is happening but is strange:

>X:0 // Id:0

>X:1 // Id:1

>X:2 // Id:2

>X:3 // Id:3

DESPUES DEL FOR

>>X:0 // Id:3

>>X:1 // Id:3

>>X:2 // Id:3

>>X:3 // Id:3

My question is: Why the info is being stored ok when inside the For loop but not when outside the For loop??

Any help is appreciated!

JSONObject::put overrides keys, therefore, as your JSONObject Event is a class field, everytime you call miPlayer::addEvent it stores the very same Event object in a new cell of EventArr, updating all the other cells (because each cell contains a pointer to your Event object). To fix this, simply use a local variable :

package miCMS;

{***}

import org.json.JSONArray;

import org.json.JSONObject;

{***}

JSONArray eventArr = new JSONArray();

{***}

public class MiPlayer{

{***}



public void addEvent(int id, int time, String file, String comment) {

    try {

        JSONObject event = new JSONObject();

        event.put("Id", id);

        event.put("Time", time);

        event.put("File", file);

        event.put("Comment", comment);

        eventArr.put(event);

    }catch ( Exception e ) {e.printStackTrace();}

}

By the way, Java Naming Conventions preconize to name variables with a lowercase first letter, and classes with a uppercase first letter :)

Problem is in this line:

 EventArr.put(Event);

each time you invoke 'addEvent' your code updates object 'Event', and because of that at the end you see values added last. You should create new instance every time

public void addEvent(int Id, int Time, String File, String Comment) {

      try {

          Event = new JSONObject();

          Event.put("Id", Id);

          Event.put("Time", Time);

          Event.put("File", File);

          Event.put("Comment", Comment);

          EventArr.put(Event);

      }catch ( Exception e ) {e.printStackTrace();}

}