package cn.xf.cp.ch02.item16;import java.util.Collection;
import java.util.Iterator;
import java.util.Set;public class ForwardingSet<E> implements Set<E>
{/*** 这个类作为转发类，内部通过复合的方式把set作为一个组件*/private final Set<E> s;public ForwardingSet(Set<E> s){this.s = s;}@Overridepublic int size(){return s.size();}@Overridepublic boolean isEmpty(){return s.isEmpty();}@Overridepublic boolean contains(Object o){return s.contains(o);}@Overridepublic Iterator<E> iterator(){return s.iterator();}@Overridepublic Object[] toArray(){return s.toArray();}@Overridepublic <T> T[] toArray(T[] a){return s.toArray(a);}@Overridepublic boolean add(E e){return s.add(e);}@Overridepublic boolean remove(Object o){return s.remove(o);}@Overridepublic boolean containsAll(Collection<?> c){return s.containsAll(c);}@Overridepublic boolean addAll(Collection<? extends E> c){return s.addAll(c);}@Overridepublic boolean retainAll(Collection<?> c){return s.retainAll(c);}@Overridepublic boolean removeAll(Collection<?> c){return s.removeAll(c);}@Overridepublic void clear(){s.clear();}}

package cn.xf.cp.ch02.item16;import java.util.Collection;
import java.util.Set;/*** *功能：包装类*时间：下午9:58:36*文件：InstrumentedSet.java *@author xiaof ** @param <E>*/
public class InstrumentedSet<E> extends ForwardingSet<E>
{private int addCount = 0;    //用来统计set添加了多少元素public InstrumentedSet(Set<E> s){super(s);}@Overridepublic boolean add(E e){++addCount;return super.add(e);}@Overridepublic boolean addAll(Collection<? extends E> c){addCount += c.size();return super.addAll(c);}public int getAddCount(){return addCount;}}