Can I call a method through an array?

Question

Can I call a method through an array?

For example, I want to create an array with pointers to call a method. Here's what I'm trying to say:

import java.util.Scanner;

public class BlankSlate {
    public static void main(String[] args) {
        Scanner kb = new Scanner(System.in);
        System.out.println("Enter a number.");
        int k = kb.nextInt();

         Array[] = //Each section will call a method };
         Array[1] = number();

         if (k==1){
             Array[1]; //calls the method
         }
    }

    private static void number(){
        System.out.println("You have called this method through an array");
    }
}

I apologize if I am not well versed in the description, or if my formatting is incorrect. Thanks for your contributions.

+3

java arrays methods call

AnotherNewbie Sep 20 '14 at 1:19

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3 answers

ericbn · Answer 1 · 2014-09-20T03:37:02+0000

As @ikh answered, yours array

should be Runnable[]

.

Runnable

is an interface that defines a method run()

.

Then you can initialize your array and the latter call the method like this:

Runnable[] array = new Runnable[ARRAY_SIZE];

// as "array[1] = number();" in your "pseudo" code
// initialize array item
array[1] = new Runnable() { public void run() { number(); } };

// as "array[1];" in your "pseudo" code
// run the method
array[1].run();

Since Java 8, you can use the lamda expression to write a simpler implementation of a functional interface. This way your array can be initialized with:

// initialize array item
array[1] = () -> number();

Then you will use array[1].run();

to run the method.

ikh · Answer 2 · 2014-09-20T01:30:34+0000

You can create an array Runnable

. In java used Runnable

instead of function pointer [C] or delegates [C #] (as far as I know)

Runnable[] arr = new Runnable[] {
    new Runnable() { public void run() { number(); } }
};
arr[0].run();

(live example)

Eduardo javier huerta yero · Answer 3 · 2014-09-20T02:38:55+0000

You can also create an array of methods and call each method that would possibly be closer to what you requested in your question. Here is the code:

public static void main(String [] args) {
    try {
        // find the method
        Method number = TestMethodCall.class.getMethod("number", (Class<?>[])null);

        // initialize the array, presumably with more than one entry
        Method [] methods = {number};

        // call method through array
        for (Method m: methods) {
            // parameter is null since method is static
            m.invoke(null);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } 
}


public static void number(){
    System.out.println("You have called this method through an array");
}

The only caveat is that the number () must be public in order to be found using the getMethod () method.

Can I call a method through an array?

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