Just wondering if somebody could check my IF ELSE statement ?

[sim18]

Hi guys, Just wondering if somebody could check my IF ELSE statements as it seems to completely skip part of my code!

Sorry about the long piece of code. Basically I open i file dialog box, then open a txt file. Read the data from it. If it is a blank line skip that line, if the line is a // line skip it, but when it reaches a flag "[ " that data should be stored as appropriate.

Thanks for any help!

public void readData()
      {
          FileDialog fileDialog = new FileDialog(mainWindow, "Open", FileDialog.LOAD);
          fileDialog.setVisible(true);
          filename = fileDialog.getFile();
          //Loads a file dialog window for the user to select a file
          
      try {
          //Preparing a Scanner that will scan the document
          Scanner input = new Scanner(new File (filename));
 
          
        while( input.hasNextLine() )//Read each line of the file
        {
               lineOfText = input.nextLine(); //Reads a line of text
               AudioVisual av;
               typeOfData = null;

               if (! lineOfText.isEmpty() && ! lineOfText.startsWith("//"))  
              { 
                  //Ignore
                }
              
              else if (lineOfText.startsWith("[")) //If this line is a flag
              {  
                  if (lineOfText.equalsIgnoreCase("[CD data]"))
                  typeOfData = "CD"; //Stores type of data to be CD
                  else if (lineOfText.equalsIgnoreCase("[DVD data]"))
                  typeOfData = "DVD"; //Stores type of data to be DVD
                  else if (lineOfText.equalsIgnoreCase("")){
                  System.out.println("Unknown data type!"); //Deal with unknown type not sure if this is right
                  }                    
                                input.useDelimiter("[ ]*(,) [ ]*"); //Use delimiter
                  
               }
               
               else if (typeOfData.equals("CD"))//Checks to make sure its CD data//When it gets to this line it skips to catch and gives NullPointerException
                  {
                    av = new CD();
                    av.extractTokens(input); //Extracts the tokens
                    addItem(av);
                  }
                
               else if (typeOfData.equals("DVD")) //Checks to make sure its DVD data
                 {
                    av = new DVD();
                    av.extractTokens(input); //Extracts the tokens
                    addItem(av);
                 }
               
                else
                 {
                  typeOfData = null; //Not sure about this line
                 }  
                  

        }
              input.close();//Closes 2nd scanner 

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

[Tolls]

Please use [code] tags [/code] when posting code, especially large chunks of it like this.

[Tolls]

while () {
   typeOfData = null;
...
   else if (typeOfData.equals("CD"))
...
}

Nowhere in between that declaration and that 'else if' do you instantiate typeOfData, so it is always null if you fall through to that bit of your if..else if...else block.

[sim18]

Do you mean moving typeOfData = null, further down in my code say to line 26, or that line 37's else if is wrong ?

Thank you

[Tolls]

I have no idea, since I have no idea what this is supposed to do.
But that is the reason you are getting a null pointer exception.