import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Set of elements with get method.
 * @author Lukáš Závitkovský
 */
public class MySet<T> implements Iterable{

    public MySet(){
        map = new HashMap<T,T>();
    }

    public void add(T obj){
        map.put(obj, obj);
    }

    public boolean isEmpty(){
        return map.isEmpty();
    }

    public void remove(T o){
        map.remove(o);
    }

    public boolean contains(T o){
        return map.containsKey(o);
    }

    public T get(T obj){
        return map.get(obj);
    }

    @Override
    public Iterator<T> iterator(){
        return new MyIterator();
    }

    private final Map<T, T> map;

    // Iterator implementation for MySet
    private class MyIterator implements Iterator<T>{

        public MyIterator(){
            it = map.entrySet().iterator();
        }

        @Override
        public boolean hasNext() {
            return it.hasNext();
        }

        @Override
        public T next() {
            return it.next().getValue();
        }

        @Override
        public void remove() {
            it.remove();
        }

        private Iterator<Entry<T,T>> it;

    }

};