CODEWITHSUNDEEP
javacollectionsiterator
Sappo
Sappo

Reputation: 39

How to create list filled with methods in Java and iterate over it (using methods)

I want to be able to create list (collection, array) filled with my own methods and in each step of iteration call the method. What's the best solution for this?

I want something like this:

List a = new List();
a.add(myCustomMethod1());
a.add(myCustomMethod2());

Object o = new Object();

for (Method m : a){
    m(o);
}

Upvotes: 2

Views: 10273

Answers (2)

Rodrigo Eggea
Rodrigo Eggea

Reputation: 124

In Java 8 and above you can create a List of Functional Interfaces to store the methods, as the following example shows:

// Create a list of Consumer
List<Consumer<String>> methodList= new ArrayList<>();

// Store the methods in the list
methodList.add(p -> method1(p));
methodList.add(p -> method2(p));
methodList.add(p -> method3(p));
methodList.forEach(f -> f.accept("Hello"));

Functions with no arguments you can use Runnable:

List<Runnable> methods = new ArrayList<>();
methods.add(() -> method1());
methods.add(() -> method2());
methods.add(() -> method3());
methods.forEach(f -> f.run());

Upvotes: 7

Ted Hopp
Ted Hopp

Reputation: 234857

In Java, you can do this with reflection by making a list of Method objects. However, an easier way is to define an interface for objects that have a method that takes an Object argument:

public interface MethodRunner {
    public void run(Object arg);
}

List<MethodRunner> a = new ArrayList<>();
a.add(new MethodRunner() {
    @Override
    public void run(Object arg) {
        myCustomMethod1(arg);
    }
});
a.add(new MethodRunner() {
    @Override
    public void run(Object arg) {
        myCustomMethod2(arg);
    }
});

Object o = new Object();

for (MethodRunner mr : a) {
    mr.run(o);
}

Upvotes: 3

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