建造者模式

模型图形:

                             Director  -->  Builder

                                                    |

                                           ConcreteBuilder -----> Product

                                             |        |       |                |   |

                                          ...     RealBuilder ..         .... RealProduct

public abstract class Product {
private ArrayList<String> sequence;
protected abstract void doSomething1();
protected abstract void doSomething2();
public void setSequence(ArrayList<String> al){
this.sequence = al;
}
public void doTheRealThing(){
for(int i = 0;i<this.sequence.size();i++){
if(this.sequence.get(i).equals("doSomething1")){
this.doSomething1();
}else if(this.sequence.get(i).equals("doSomething2")){
this.doSomething2();
}
}
}
}

public class RealProd1 extends Product {

@Override
protected void doSomething1() {
// TODO Auto-generated method stub
System.out.println("I am the doSomething1 in the RealProd1");
}

@Override
protected void doSomething2() {
// TODO Auto-generated method stub
System.out.println("I am the doSomething2 in the RealProd1");
}

}

public class RealProd1Builder implements Builder {
private RealProd1 p;
public void setSequence(ArrayList<String> al) {
// TODO Auto-generated method stub
p = new RealProd1();
p.setSequence(al);
}

public Product getProduct() {
// TODO Auto-generated method stub
return this.p;
}

}

public class Director {
public Product getRealProd1(){
ArrayList<String> al = new ArrayList<String>();
al.add("doSomething1");
al.add("doSomething2");
Product p = new RealProd1();
p.setSequence(al);
return p;
}
public Product getRealProd2(){
return null;
}
}

测试方法：

public static void main(String[] args) {
// TODO Auto-generated method stub
Director d = new Director();
d.getRealProd1().doTheRealThing();
}

说明：产品侧的类定义和模板方法类似，只是通过arraylist来动态设置具体方法的执行顺序，

建造侧类的定义：只有设置al和返回产品类。具体的al实例对象放到了director类来设置。故只要改director的al就可以控制prod的具体实现了。