建造者模式

1.定义：将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示；
　　　　用户只需指定需要建造的类型就可以得到它们，建造过程及细节不需要知道。

2.类型：创建型

3.适用场景：如果一个对象有非常复杂的内部结构(很多属性)；想把复杂对象的创建和使用分离。

4.优点：封装性好，创建和使用分离；扩展性好、建造类之间独立、一定程度上解耦。

5.缺点：产生多余的Builder对象；产品内部发生变化，建造者都要修改，成本较大

6.实例目录package

7.实例UML类图

内部类

8.代码

package com.geely.design.pattern.creational.builder;

public class Course {
    private String courseName;
    private String coursePPT;
    private String courseVideo;
    private String courseArticle;
    private String 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 getCourseArticle() {
        return courseArticle;
    }

    public void setCourseArticle(String courseArticle) {
        this.courseArticle = courseArticle;
    }

    public String getCourseQA() {
        return courseQA;
    }

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

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

package com.geely.design.pattern.creational.builder;

public abstract class CourseBuilder {

    public abstract void builderCourseName(String courseName);
    public abstract void builderCoursePPT(String coursePPT);
    public abstract void builderCourseVideo(String courseVideo);
    public abstract void builderCourseArticle(String courseArticle);
    public abstract void builderCourseQA(String courseQA);

    public abstract Course makeCourse();
}

package com.geely.design.pattern.creational.builder;

public class CourseActualBuilder extends CourseBuilder{
    private Course course = new Course();
    @Override
    public void builderCourseName(String courseName) {
        course.setCourseName(courseName);
    }

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

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

    @Override
    public void builderCourseArticle(String courseArticle) {
        course.setCourseArticle(courseArticle);
    }

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

    @Override
    public Course makeCourse() {
        return course;
    }
}

package com.geely.design.pattern.creational.builder;

public class Coach {
    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.builderCourseArticle(courseArticle);
        this.courseBuilder.builderCourseName(courseName);
        this.courseBuilder.builderCoursePPT(coursePPT);
        this.courseBuilder.builderCourseVideo(courseVideo);
        this.courseBuilder.builderCourseQA(courseQA);
        return this.courseBuilder.makeCourse();
    }
}

package com.geely.design.pattern.creational.builder;

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设计模式精讲",
                "JAVA设计模式精讲PPT",
                "JAVA设计模式精讲视频",
                "JAVA设计模式精讲手记",
                "JAVA设计模式精讲问答");
        System.out.println(course);
    }
}

 内部类

package com.geely.design.pattern.creational.builder.v2;

public class Course {
    private String courseName;
    private String coursePPT;
    private String courseVideo;
    private String courseArticle;
    private String courseQA;

    public Course(CourseBuilder courseBuilder){
        this.courseName = courseBuilder.courseName;
        this.coursePPT = courseBuilder.coursePPT;
        this.courseVideo = courseBuilder.courseVideo;
        this.courseArticle = courseBuilder.courseArticle;
        this.courseQA = courseBuilder.courseQA;
    }
    
    @Override
    public String toString() {
        return "Course{" +
                "courseName='" + courseName + '\'' +
                ", coursePPT='" + coursePPT + '\'' +
                ", courseVideo='" + courseVideo + '\'' +
                ", courseArticle='" + courseArticle + '\'' +
                ", courseQA='" + courseQA + '\'' +
                '}';
    }

    public static class CourseBuilder {
        private String courseName;
        private String coursePPT;
        private String courseVideo;
        private String courseArticle;
        private String courseQA;

        public CourseBuilder builderCourseName(String courseName){
            this.courseName = courseName;
            return this;
        }
        public CourseBuilder builderCoursePPT(String coursePPT){
            this.coursePPT = coursePPT;
            return this;
        }
        public CourseBuilder builderCourseVideo(String courseVideo){
            this.courseVideo = courseVideo;
            return this;
        }

        public CourseBuilder builderCourseArticle(String courseArticle){
            this.courseArticle = courseArticle;
            return this;
        }
        public CourseBuilder builderCourseQA(String courseQA){
            this.courseQA = courseQA;
            return this;
        }

        public Course builder(){
            return new Course(this);
        }
    }
}

package com.geely.design.pattern.creational.builder.v2;

import avro.shaded.com.google.common.collect.ImmutableSet;

import java.util.Set;

public class Test {
    public static void main(String[] args) {
        Course course = new Course.CourseBuilder()
                .builderCourseArticle("JAVA设计模式精讲手记")
                .builderCourseName("JAVA设计模式精讲")
                .builderCoursePPT("JAVA设计模式精讲PPT")
                .builderCourseQA("JAVA设计模式精讲问答")
                .builderCourseVideo("JAVA设计模式精讲视频").builder();
        System.out.println(course);
        Set<String> set = ImmutableSet.<String>builder().add("a").add("b").build();
        System.out.println(set);
    }
}