数据结构bag

摘要: bag

package structure;

import java.util.HashMap;

import java.util.Iterator;

/**

* Created by kangyabo on 2015/12/21.

*/

public class Bag<E> implements Iterable {

private HashMap<E, Object> map;

public Bag(){

map = new HashMap<E, Object>();

}

public void add(E item) {

map.put(item, null);

}

public int size() {

return map.size();

}

public boolean isEmpty() {

return map.isEmpty();

}

public Iterator<E> iterator() {

return map.keySet().iterator();

}

}