CODEWITHSUNDEEP
java
user2556552
user2556552

Reputation:

How can I do ArrayList of Methods?

Is it posible in java?

void aaa(){}

ArrayList<Method> list = new ArrayList<Method>();
list.add(aaa);

If it isn't, how i can realize collection of methods (functions).
I want to get some method by ID.

Upvotes: 1

Views: 1080

Answers (4)

arshajii
arshajii

Reputation: 129507

You can do something like:

interface VoidFunction {
    void evaluate();
}

...

List<VoidFunction> list = new ArrayList<>();

VoidFunction aaa = new VoidFunction() {
    @Override
    public void evaluate() {
        aaa();
    }
}

list.add(aaa);

In Java 8 this should be much easier and nicer:

List<Consumer<Void>> list = new ArrayList<>();

Consumer<Void> aaa = () -> {...};

list.add(aaa);

(I believe I have the syntax right)

If you already have the aaa method defined as a regular method, you'll be able to do something like:

list.add(MyClass::aaa);

Upvotes: 4

Sachin Thapa
Sachin Thapa

Reputation: 3709

You can call following method of Class

public Method[] getMethods() throws SecurityException

Returns an array containing Method objects reflecting all the public member methods of the class or interface represented by this Class object, including those declared by the class or interface and those inherited from superclasses and superinterfaces.

public Method[] getDeclaredMethods() throws SecurityException

Returns an array of Method objects reflecting all the methods declared by the class or interface represented by this Class object. This includes public, protected, default (package) access, and private methods, but excludes inherited methods.

Read more here

Cheers !!

Upvotes: 0

Garrett Hall
Garrett Hall

Reputation: 30032

You need to use reflection to get the Method, e.g.

this.getClass().getMethod("aaa")

Alternatively, if you don't need to access methods defined on a class, you can use Callables.

ArrayList<Callable> list = new ArrayList<Callable>();
list.add(new Callable() {
   public String call() {
     return "asdf";
   }
});

Upvotes: 2

hveiga
hveiga

Reputation: 6915

I believe you can do it, but you need to use reflection to get the methods from a class/object. Maybe this links helps: http://tutorials.jenkov.com/java-reflection/methods.html

The way you have done it does not work.

Upvotes: 0

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