1) interface to define build methods.
============== Builder.java ================
package test.pattern.builder;
/**
* interface
*
*/
public interface Builder {
public abstract void doPart1();
public abstract void doPart2(String para);
public abstract void doPart3(int para);
public abstract Product getProduct();
}
2) to create product object
============== Director.java =============
package test.pattern.builder;
public class Director {
private Builder builder;
public Director(Builder builder) {
this.builder = builder;
}
public Product construct(String para, int para2) {
builder.doPart1();
builder.doPart2(para);
builder.doPart3(para2);
Product product = builder.getProduct();
return product;
}
}
3) product class
============== Product.java =============
package test.pattern.builder;
public class Product {
private String component1;
private int component2;
// getter and setter methods
}
4) concrete builder:
a) implement the methods defined in above interface to build the product step by step
b) return the product instance
============== ConcreteBuilder1.java ==================
package test.pattern.builder;
public class ConcreteBuilder1 implements Builder {
Product prod = new Product();
public void doPart1() {
System.out.println("execute builder1:part1");
}
public void doPart2(String para) {
System.out.println("execute builder1:part2:" + para);
prod.setComponent1(para);
}
public void doPart3(int para) {
System.out.println("execute builder1:part3:" + para);
prod.setComponent2(para);
}
public Product getProduct() {
return prod;
}
}
=============== ConcreteBuilder2.java ==============
package test.pattern.builder;
public class ConcreteBuilder2 implements Builder {
Product prod = new Product();
public void doPart1() {
System.out.println("execute builder2:part1");
}
public void doPart2(String para) {
System.out.println("execute builder2:part2:" + para);
prod.setComponent1(para);
}
public void doPart3(int para) {
System.out.println("execute builder2:part3:" + para);
prod.setComponent2(para);
}
public Product getProduct() {
return prod;
}
}
5) test class
============== Client.java =================
package test.pattern.builder;
public class Client {
public static void main(String[] args) {
Director director = new Director(new ConcreteBuilder1());
Product prod = director.construct("do something", 4);
System.out.println("got: " + prod.getComponent1());
System.out.println("got: " + prod.getComponent2());
director = new Director(new ConcreteBuilder2());
prod = director.construct("do something else", 5);
System.out.println("got: " + prod.getComponent1());
System.out.println("got: " + prod.getComponent2());
}
}
This is the output:
execute builder1:part1
execute builder1:part2:do something
execute builder1:part3:4
got: do something
got: 4
execute builder2:part1
execute builder2:part2:do something else
execute builder2:part3:5
got: do something else
got: 5
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