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Thread: Identifying calling object

  1. #1
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    Default Identifying calling object

    Hey guys!

    I'm trying to do this:

    int x;
    x = orc.getFrags;  //orc extends player

    In class player I have:
    public int getFrags(){
     
        If (this.getClass().getName().equals("orc")){
            return 5;
        }
    }

    But it doesn't work. I'm guessing its because "this" returns the class player and not the subclass orc. Is there any way to determine which object/subclass called a method from a superclass?


  2. #2
    Super Moderator copeg's Avatar
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    Default Re: Identifying calling object

    Add a println in the getFrags method to print the class name, you will then see which class it is referring to, and what the name actually is.

  3. #3
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    Default Re: Identifying calling object

    It does indeed return the class "player". Is there any way to find out if the method was called with regards to a subclass like orc, elf etc?

  4. #4
    Super Moderator copeg's Avatar
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    Exclamation Re: Identifying calling object

    Quote Originally Posted by frogfury View Post
    It does indeed return the class "player". Is there any way to find out if the method was called with regards to a subclass like orc, elf etc?
    This is not the behavior on my machine. Is orc just a reference to an instance of Player, or is it actually a class which extends Player? What exactly are you trying to accomplish

    public class Test{
    	public static void main(String[] args) throws Exception{
    		Player pla = new Temp();
    		pla.getFrags();
    	}
     
    	private static class Player {
    		public void getFrags(){
    			System.out.println(this.getClass().getName());
    		}
    	}
     
    	private static class Temp extends Player{
     
    	}
    }

    Prints out Temp, not Player

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    frogfury (October 25th, 2010)

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    Member Darryl.Burke's Avatar
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    Default Re: Identifying calling object

    Apart from all that, if you need to know which subclass's method is invoked, it's almost always a sign of misuse of inheritance.

    db

  7. The Following User Says Thank You to Darryl.Burke For This Useful Post:

    frogfury (October 25th, 2010)

  8. #6
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    Default Re: Identifying calling object

    Reading copeg's example I just realized that I had set my main class to private. No wonder it wasn't working...

    Thanks a lot for your time guys!

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    Super Moderator helloworld922's Avatar
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    Default Re: Identifying calling object

    Quote Originally Posted by Darryl.Burke View Post
    Apart from all that, if you need to know which subclass's method is invoked, it's almost always a sign of misuse of inheritance.

    db
    ^^ this is very important to keep in mind, as this is the basis for creating well-formed polymorphic classes, as well as properly using inheritance.

    If you want a way to differentiate the name of different players, put a string field in your base class.

    public abstract class Player
    {
        public final String name;
     
        public Player(String name)
        {
            this.name = name;
        }
    }

    public class Orc extends Player
    {
        public Orc()
        {
            super("orc");
        }
    }

    public static void main(String[] args)
    {
        Player p1 = new Orc();
        Player p2 = new Wizzard(); // code for Wizzard not provided, but it's something similar to Orc
        System.out.println(p1.name);
        System.out.println(p2.name);
    }

    If you have a set list of names possible, simply use an enumeration instead of a string.

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