装饰模式:动态地给一个对象添加一些额外的职责。就增加功能来说，Decorator模式相比生成子类更为灵活。以下是例子：
public class SquarePeg implements Work{
public void insert() {
System.out.println("方形粧插入"); } }
public class Decorator implements Work{
private Work work;
private ArrayList others = new ArrayList();
public Decorator(Work work){
this.work = work;
others.add("挖坑");
others.add("钉木板"); }
public void insert() {
newMethod(); }
public void newMethod(){
//添加的工作
otherMethod();
//原有的工作
work.insert(); }
public void otherMethod(){
ListIterator listIterator = others.listIterator();
while(listIterator.hasNext()){
System.out.println((String)listIterator.next()+"正在进行"); } } }
//测试类
public class Test {
public static void main(String[] args) {
Work squarePeg = new SquarePeg();
Work decorator = new Decorator(squarePeg);
decorator.insert(); } }