来自已加载类的Java Call类函数

Question

How would I, if possible, call a function in my Main class in the class that I load? (I know that is impossible to understand, so I'll explain)

IE:

public class SomeClass
{
     public SomeClass
     {
          //load a class here
     }

     public void FuncToCall() {}
}

//In a separate file, dynamically loaded.
public class LoadedClass
{
     public LoadedClass
     {
          //Call a function in the class that loads this
          SomeClass.FuncToCall();
     }
}

So I would end up having 2 files: SomeClass.class and LoadedClass.class. I guess my main question is, how do I reference SomeClass in LoadedClass?

**EDIT:

So maybe I should better explain the use case. A java program dynamically loads the "SomeClass" script from a folder. The script then downloads a .jar file from the internet and opens and runs the "LoadedClass" script within that. How do I use functions in SomeClass in LoadedClass if SomeClass isn't in the same .jar or in a .jar at all?

Answer 1

You just do it..

If they are in different packages you have to either import the class or use the fully qualified name.

Let me see if I get it.

Check this running sample with modifications to your source code:

C:\Users\oreyes\java>type SomeClass.java LoadedClass.java Main.java
//SomeClass.java
public class SomeClass{
     public SomeClass () /* added () */ {
          //load a class here
          LoadedClass lc = new LoadedClass( this );
     }
     public  void funcToCall() {
         System.out.println("SomeClass.functToCall: Being invoked :)");
     }
}
//LoadedClass.java
//In a separate file, dynamically loaded.
public class LoadedClass {
     public LoadedClass( SomeClass sc )/*added () */ {
          //Call a function in the class that loads this
          //SomeClass.funcToCall();
          sc.funcToCall();
     }
}
//Main.java
//
public class Main {
    public static void main( String ... args ) {
        new SomeClass();
    }
}
C:\Users\oreyes\java>javac SomeClass.java LoadedClass.java Main.java
C:\Users\oreyes\java>java Main
SomeClass.functToCall: Being invoked :)
C:\Users\oreyes\java>

What a did was to pass a reference of the loader class into the loaded, and from there...just invoke the method.

I hope this helps.

EDIT

As per your comment it looks like what you need is to use Reflection

Answer 2

You do it right now.

We call it --> Recursivity (if you call the same function from the function you call) Or simply.. a redirection.. You learn little by little what is the POTENTIAL of the programming :D

Welcome to StackOverflow :D Good Luck!

Answer 3

because if you call a class from another class, you need to create an object before. (OOP) Example:

Class X{ public functionX(){}}
Class Y { 
   X object = new X(); //Create an object to access to the function X
    public functionY(){ 
             object.functionX(); //you call the function from Class X
    }
}