Builder パターン

public class Director {
    public Director() {}

    /** Builderを働かせる */
    public void build(Builder builder){
        builder.setMax();
        builder.setName();
        builder.setColor();
    }
}

abstract class Builder {
    /** 最大人数の設定 */
    abstract public void setMax();

    /** 色の設定 */
    abstract public void setColor();

    /** 名前の設定 */
    abstract public void setName();

    /** 完成状態 */
    abstract public String myInfo();
}

import java.awt.Color;

public class RedWagon extends Builder{
    public int max;
    public String name;
    public Color color;

    public void setMax(){
        this.max = 10;
    }

    public void setName(){
        this.name = "赤いワゴン";
    }

    public void setColor(){
        color = Color.RED;
    }

    public String myInfo(){
        return "■車体の情報\n" + this.name + "\n"
               + this.max + "人乗り\n"
               + this.color.toString();
    }
}

import java.awt.Color;

public class BlueBike extends Builder{
    public int max;
    public String name;
    public Color color;

    public void setMax(){
        this.max = 2;
    }

    public void setName(){
        this.name = "二人乗りバイク";
    }

    public void setColor(){
        color = Color.BLUE;
    }

    public String myInfo(){
        return "■車体の情報\n" + this.name + "\n"
               + this.max + "人乗り\n"
               + this.color.toString();
    }
}

public class Main {
    public static void main(String[] args){
        Director director = null;
        Builder builder = null;

        director = new Director();
        builder = new RedWagon();
        director.build(builder);
        System.out.println(builder.myInfo());

        builder = new BlueBike();
        director.build(builder);
        System.out.println(builder.myInfo());
    }
}

■車体の情報
赤いワゴン
10人乗り
java.awt.Color[r=255,g=0,b=0]
■車体の情報
二人乗りバイク
2人乗り
java.awt.Color[r=0,g=0,b=255]