java设计模式——建造者模式

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《大话设计模式》第十三章

package ch13;public abstract class Builder {public abstract void buildPartA();public abstract void buildPartB();public abstract Product getResult();}

package ch13;public class ConcreteBuilder1 extends Builder {private Product product = new Product();@Overridepublic void buildPartA() {product.add("部件A");}@Overridepublic void buildPartB() {product.add("部件B");}@Overridepublic Product getResult() {return product;}}

package ch13;public class ConcreteBuilder2 extends Builder {private Product product = new Product();@Overridepublic void buildPartA() {product.add("部件X");}@Overridepublic void buildPartB() {product.add("部件Y");}@Overridepublic Product getResult() {return product;}}

package ch13;public class Director {public void construct(Builder builder) {builder.buildPartA();builder.buildPartB();}}

package ch13;import java.util.ArrayList;import java.util.List;public class Product {private List<String> list = new ArrayList<String>();public void add(String part) {list.add(part);}public void show() {for (int i = 0; i < list.size(); i++) {System.out.println(list.get(i));}}}

package ch13;public class Client {/** * @param args */public static void main(String[] args) {Director director = new Director();Builder b1 = new ConcreteBuilder1();Builder b2 = new ConcreteBuilder2();director.construct(b1);Product p1 = b1.getResult();p1.show();director.construct(b2);Product p2 = b2.getResult();p2.show();}}

结合JDK里的java.lang.StringBuilder，就比较好理解建造者模式了，上面的代码，其实就是把一些部件，添加到list里面去，相当于StringBuilder里的append方法，只不过，上面的代码，添加的东西是写死的，没有参数，而StringBuilder里的是灵活的。