What I would like to do is send a function as parameter to other class' function. For example, I have UI.java class for UI and Timer.java class for the logic. So I would like to pass function of logic class to UI so that once a button is clicked, it will call function from Timer.java.
How can I do that? Is it recommended? standard for application development?
Use a functional interface such as Runnable and a method reference:
class Bar
{
public void doSomething() { /* ... */ }
}
class Foo
{
private Runnable runnable;
Foo(Runnable runnable)
{
this.runnable = runnable;
}
public void onCompletion()
{
this.runnable.run();
}
}
Bar bar = new Bar();
Foo foo = new Foo(bar::doSomething);
foo.onCompletion();
The exact functional interface you'll want will depend on your use case. Have a look in the package java.util.function to find the one you need.
Callable<T>might be one of it.Function<T, R>might be an alternative and there are a lot of others - it all depends on what you're actually trying to do and what your code looks like.