java - 在 Java 中创建迭代器

Question

我有以下类(class):

public abstract class MapObjects<MapleMapObject> {
    private Map map;
    private HashMap<Integer, MapleMapObject> objects;

    public MapObjects(Map map) {
        this.map = map;
        this.objects = new HashMap<>();
    }

    public void add(MapleMapObject object) {
        objects.put(map.getObjectId(), object);

        onAdd();
    }

    public void remove(MapleMapObject object) {
        onRemove();

        objects.remove(object.getObjectId());
    }

    protected abstract void onAdd();

    protected abstract void onRemove();
}

我想创建一个迭代器，以便我可以迭代从此类扩展的类。例如，如果我有一个名为 MapCharacters extends MapObjects<Character> 的类，我希望能够执行以下操作:

characters = new MapCharacters(this);
for (Character character : characters)

如何实现？

Answer 1

如果您只想迭代 objects 映射，您可以只对其调用 values()，然后从该值集创建一个迭代器:

public abstract class MapObjects<MapleMapObject> implements Iterable<MapleMapObject> {

    ...

    @Override public Iterator<MapleMapObject> iterator() {
        return objects.values().iterator();
    }
}