设计模式之建造者模式

建造者模式

将一个复杂的对象的构建与他的表示分离，使得同样的构建过程可以创建不同的表示

Product类

package com.hml.builder;

import java.util.ArrayList;
import java.util.List;

public class Product {
   private List<String> parts = new ArrayList<String>();
   
   public void addPart(String part) {
       parts.add(part);
   }
   public void show() {
       
   }
}

Builder

package com.hml.builder;

public interface Builder {
    public void buildPathA();
    public void buildPathB();
    
    public Product getResult();
}

ConcreateBuilderA

package com.hml.builder;

public class ConcreateBuilderA implements Builder {
    
    private Product p = new Product();

    public void buildPathA() {
       p.addPart("A");
    }

    public void buildPathB() {
        p.addPart("B");
    }

    public Product getResult() {
        return p;
    }

}

ConcreateBuilderB

package com.hml.builder;

public class ConcreateBuilderB implements Builder {
    
    private Product p = new Product();

    public void buildPathA() {
       p.addPart("A");
    }

    public void buildPathB() {
        p.addPart("B");
    }

    public Product getResult() {
        return p;
    }

}

Director

package com.hml.builder;

public class Director {
    public Director(Builder builder) {
        builder.buildPathA();
        builder.buildPathB();
    }
}

类图

构建者模式主要是用于创建一些比较复杂的对象，这些对象内部构建间的建造顺序通常是稳定的，但对象内部的构建通常面临着复杂的变化。