設計模式之建造者模式

建造者模式

定義：將一個複雜對象的構建與它的表示分離，使得同樣的構建過程可以創建不同的表示
特點：用戶只需要指定建造的類型就可以得到他們，建造過程及細節不需要知道
類型：創建型

適用場景：
·如果一個對象有非常複雜的內部結構(很多屬性)
·想把複雜對象的創建和使用分離
優點：
·封裝性好
·擴展性好、建造類之間獨立、一定程度上解耦
缺點：
·產品多餘的builder對象
·產品內部發生變化，建造者都要修改，成本較大

public class Course {
    private String courseName;
    private String coursePPT;
    private String courseVideo;
    private String courseAriticle;

    private String courseQA;

    @Override
    public String toString() {
        return "Course{" +
                "courseName='" + courseName + '\'' +
                ", coursePPT='" + coursePPT + '\'' +
                ", courseVideo='" + courseVideo + '\'' +
                ", courseAriticle='" + courseAriticle + '\'' +
                ", courseQA='" + courseQA + '\'' +
                '}';
    }
    public String getCourseName() {
        return courseName;
    }

    public void setCourseName(String courseName) {
        this.courseName = courseName;
    }

    public String getCoursePPT() {
        return coursePPT;
    }

    public void setCoursePPT(String coursePPT) {
        this.coursePPT = coursePPT;
    }

    public String getCourseVideo() {
        return courseVideo;
    }

    public void setCourseVideo(String courseVideo) {
        this.courseVideo = courseVideo;
    }

    public String getCourseAriticle() {
        return courseAriticle;
    }

    public void setCourseAriticle(String courseAriticle) {
        this.courseAriticle = courseAriticle;
    }

    public String getCourseQA() {
        return courseQA;
    }

    public void setCourseQA(String courseQA) {
        this.courseQA = courseQA;
    }
}

public class CourseActualBuilder extends CourseBuilder{

    private Course course = new Course();
    @Override
    public void builderoCurseName(String courseName) {
        course.setCourseName(courseName);
    }

    @Override
    public void builderoCursPPT(String coursePPT) {
        course.setCoursePPT(coursePPT);
    }

    @Override
    public void builderoCurseVideo(String courseVideo) {
        course.setCourseVideo(courseVideo);
    }

    @Override
    public void builderoCurseAriticle(String courseAriticle) {
        course.setCourseAriticle(courseAriticle);
    }

    @Override
    public void builderoCurseQA(String courseQA) {
        course.setCourseQA(courseQA);
    }

    @Override
    public Course makeCourse() {

        return course;
    }
}

public abstract  class CourseBuilder {
    private String courseName;
    private String coursePPT;
    private String courseVideo;
    private String courseAriticle;

    private String courseQA;

    public abstract void builderoCurseName(String courseName);
    public abstract void builderoCursPPT(String coursePPT);
    public abstract void builderoCurseVideo(String courseVideo);
    public abstract void builderoCurseAriticle(String courseAriticle);
    public abstract void builderoCurseQA(String courseQA);

    public abstract Course makeCourse();
}

public class Coach {
	//真正創建課程的類
    private CourseBuilder courseBuilder;

    public void setCourseBuilder(CourseBuilder courseBuilder) {
        this.courseBuilder = courseBuilder;
    }

    public Course makeCourse(String courseName,String coursePPT,String courseVideo,
                             String courseArticle,String courseQA){
        this.courseBuilder.builderoCurseName(courseName);
        this.courseBuilder.builderoCursPPT(coursePPT);
        this.courseBuilder.builderoCurseVideo(courseVideo);
        this.courseBuilder.builderoCurseAriticle(courseArticle);
        this.courseBuilder.builderoCurseQA(courseQA);

        return this.courseBuilder.makeCourse();
    }
}

public class Test {
    public static void main(String[] args) {
        CourseBuilder courseBuilder =  new CourseActualBuilder();
        Coach coach = new Coach();
        coach.setCourseBuilder(courseBuilder);

        Course course = coach.makeCourse("java設計模式精講",
                "java設計模式精講PPT",
                "java設計模式精講Video",
                "java設計模式精講Article",
                "java設計模式精講QA");

        System.out.println(course);

    }
}