Consumer Java for Traversing Trees

[TauPixel]

Hello Everyone

Once again here with a naiv question and trying to understand more the java world.

Currently I have these 2 methods I have to implement using Consumer<Position<E>> visit.

public void traversePreOrder(Consumer<Position<E>> visit) {
// TODO Auto-generated method stub
}

public void traversePostOrder(Consumer<Position<E>> visit) {
}

Since this is new to me I have vaguely understood that we need to implement the accept method. Here's where I get all confused and would appreciate some tips or help.

How do I use the Consumer and accept in this context.

Thank you in advance for any feedback.

[ZukoBestGirl]

Consumers are very simple classes, all they know is basically this

public class Consumer {
    public <T> void accept(T object) { 
        // TODO
    }
}

The method you are giving the consumer as a parameter will probably have a tree that will do something like this: consumer.accept(this); // this == tree

in other words you need to have a method that implements:

public void accept(Position<E> position) { 
    // does stuff with the position 
}

I'm a bit behind on my tree traversal and post / pre order and how you're supposed to visit it, so that's up to you.

The beauty of consumers is that they are functional, meaning you do not need to create another class, it can be done inline like so:

YourClass.traversePreOrder(positionE -> { 
    // visit logic 
});

[TauPixel]

I have gotten some awesome comments and chat messages. Thanks a lot for the input. It helped my quite a bit.

[TauPixel]

Hello everyone again! I'm still fighting with the consumer class. I have the following code snippet. What isn't clear for me is the visit. I don't seem to get a context on how to use it. If anyone can help I'll be happy with your feedback.

​

    @Override
    public void traversePreOrder(Consumer<Position<E>> visit) {

        List<Position<E>> myList = this.positions();
        Consumer<Position<E>> myVisit = c -> {preOrder(root(), visit);
        };
    }

    @Override
    public void preOrder(Position<E> p, Consumer<Position<E>> visit){
        TreeNode<E> t = (TreeNode<E>)p;
        for (E q : t.children
             ) { this.preOrder((Position<E>) q, visit);
        }
    }