Java - best way to call a method of each object in a collection

Question

I'm trying to make a little 2D game / game engine in Java.

Each type of object which is the scene extends the class "Object" which has an abstract method "tick()". Furthermore there's a class called "Scene" which has a HashMap containing all the objects in the scene. I want the scene to call the method "tick()" of every object in the HashMap (60 times per second).

public class Scene {
  private HashMap<String, Object> objs; //HashMap containing all the objects

  private void tick() {
    for(Entry<String, Object> e : objs.entrySet()) {
      Object o = e.value();
      o.tick();
    }
  }

  [...]
}

Now I'm wondering if there is a better, more elegant way to achieve this. Maybe by creating an EventObject & EventListener or by using an Observable and make each object an Observer?

What I would change first is the name of the class Object. You'll have constant clashes with the standard, auto-imported java.lang.Object class. — JB Nizet, Nov 10 '15 at 17:06
Ok so you think that using the for loop is the best / simplest way to achieve this? — Marvin, Nov 10 '15 at 17:08

score 2 · Accepted Answer · answered Nov 10 '15 at 17:04

2

for (MyOb o: objs.values()) {
    o.tick();
}

You could also do this using the stream API in Java 8:

objs.values().forEach(v -> v.tick());

answered Nov 10 '15 at 17:04

Tim B

39,784
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score 2 · Answer 2 · answered Nov 10 '15 at 17:06

2

objs.forEach((k, v) -> v.tick());

answered Nov 10 '15 at 17:06

Tahar Bakir

696
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Java - best way to call a method of each object in a collection

2 Answers2