设计模式（三） 建造者模式

核心本质：

　　分离了对象子组件的单独构造（由Builder来负责）和装配（由Director负责）。从而可以构造出复杂的对象。

使用性：

　　某个对象的构建过程复杂的情况下

特点：

由于实现了构造和装配的解耦。不同的构建器，相同的装配，也可以做出不同的对象；相同的构建器，不同的装配顺序也可以做出不同的对象。也就是实现了构建算法，装配算法的解耦，实现了更好的复用

应用场景：

实现例子代码：

package com.lp.builder;

public class AirShip {
    private OrbitalModule orbitalModule;//轨道舱
    private Engine engine; //发动机
    private EscapeTower escapeTower; //逃逸舱
    public OrbitalModule getOrbitalModule() {
        return orbitalModule;
    }
    public void setOrbitalModule(OrbitalModule orbitalModule) {
        this.orbitalModule = orbitalModule;
    }
    public Engine getEngine() {
        return engine;
    }
    public void setEngine(Engine engine) {
        this.engine = engine;
    }
    public EscapeTower getEscapeTower() {
        return escapeTower;
    }
    public void setEscapeTower(EscapeTower escapeTower) {
        this.escapeTower = escapeTower;
    }

}

class OrbitalModule{
    private String name;
    OrbitalModule (String name){
        this.name = name;
    }
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

class Engine{
    private String name;

    Engine (String name){
        this.name = name;
    }
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

class EscapeTower{
    private String name;

    EscapeTower (String name){
        this.name = name;
    }
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

飞船以及可以被装配的构建

package com.lp.builder;

public interface AirShipBuilder {
    Engine builderEngine();
    OrbitalModule builderOrbitaModule();
    EscapeTower builderEscaperTower();
}

飞船构造接口

package com.lp.builder;
//组装飞船
public interface AirShipDirector {
        AirShip directAirShip();
}

飞船装配接口

package com.lp.builder;

public class LpAirShipBuilder implements AirShipBuilder{

    @Override
    public Engine builderEngine() {
        System.out.println("构建李鹏牌发动机");
        return new Engine("李鹏牌发动机");
    }

    @Override
    public OrbitalModule builderOrbitaModule() {
        System.out.println("构建李鹏牌轨道舱");
        return new OrbitalModule("李鹏牌轨道舱");
    }

    @Override
    public EscapeTower builderEscaperTower() {
        System.out.println("构建李鹏牌逃逸舱");
        return new EscapeTower("李鹏牌逃逸舱");
    }

    //StringBuildr
}

李鹏的飞船构造接口

package com.lp.builder;

public class LpAirShipDirector implements AirShipDirector {

    private AirShipBuilder builder;

    LpAirShipDirector(AirShipBuilder builder){
        this.builder = builder;
    }

    @Override
    public AirShip directAirShip() {
        Engine e = builder.builderEngine();
        OrbitalModule o = builder.builderOrbitaModule();
        EscapeTower es = builder.builderEscaperTower();
        AirShip ship = new AirShip();
        ship.setEngine(e);
        ship.setEscapeTower(es);
        ship.setOrbitalModule(o);
        return ship;
    }
}

李鹏的飞船装配接口