2021.11.29_빌더패턴04.자바와스프링에서찾아보는패턴

자바

스트링빌더와 버퍼

StringBuilder

• 스트링 빌더 , 동기화 안쓰는 api

StringBuilder stringBuilder = new StringBuilder();
String result = stringBuilder.append("whiteship").append("keesum").toString();
System.out.println(result);

• 일종의 빌더패턴이라고 할 수 있음

Stream.Builder

Stream.Builder<String> stringStreamBuilder = Stream.builder();
stream<String> names = stringStreamBuilder.add("keesun").add("whiteship").build();
names.forEach(System.out::println);

• 스트링 만들때 빌더와 비슷하게 만들 수 있음

stream<String> names = Stream.<String>builder().add("keesun").add("whiteship").build();
names.forEach(System.out::println);

• 재네릭을 이용해서 줄일 수 있음

lombok 애노테이션

• 디펜던시 추가하고
• Enable annotation 그거 활성화해주면됨

package me.whiteship.designpatterns._01_creational_patterns._04_builder._03_java;

import lombok.Builder;

@Builder
public class LombokExample {

    private String title;

    private int nights;

    private int days;

    public static void main(String[] args) {
        LombokExample trip = LombokExample.builder()
                .title("여행")
                .nights(2)
                .days(3)
                .build();
    }
}

• 알아서 빌더패턴같이 사용할 수 있음

스프링

package me.whiteship.designpatterns._01_creational_patterns._04_builder._03_java;

import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;

public class SpringExample {

    public static void main(String[] args) {
        UriComponents howToStudyJava = UriComponentsBuilder.newInstance()
                .scheme("http")
                .host("www.whiteship.me")
                .path("java playlist ep1")
                .build().encode();
        System.out.println(howToStudyJava);
    }
}

• 이렇게 하면 uri 안전하게 만들 수 있음
• 이전에 우리가 중복된 변수를 썼는데
• before

import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;

public class DefaultTourBuilder implements TourPlanBuilder {

    private String title;

    private int nights;

    private int days;

    private LocalDate startDate;

    private String whereToStay;

    private List<DetailPlan> plans;

    @Override
    public TourPlanBuilder nightsAndDays(int nights, int days) {
        this.nights = nights;
        this.days = days;
        return this;
    }
  ...
}

// 빌더 
package me.whiteship.designpatterns._01_creational_patterns._04_builder._02_after;

import me.whiteship.designpatterns._01_creational_patterns._04_builder._01_before.TourPlan;

import java.time.LocalDate;

public interface TourPlanBuilder {

    TourPlanBuilder nightsAndDays(int nights, int days);

    TourPlanBuilder title(String title);

    TourPlanBuilder startDate(LocalDate localDate);

    TourPlanBuilder whereToStay(String whereToStay);

    TourPlanBuilder addPlan(int day, String plan);

    TourPlan getPlan();

}

• after

import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;

public class DefaultTourBuilder implements TourPlanBuilder {

	

	private TourPlan tourPlan;
  public TourPlanBuilder newInstance(){
    this.tourPlan = new TourPlan();
    return this;
  }
    @Override
    public TourPlanBuilder nightsAndDays(int nights, int days) {
        this.tourPlan.setNights(nights);// 이렇게 변수를 중복을 가지고 있지 않아도 쓸 수 있음
        this.days = days;
        return this;
    }
  ...
}

// 빌더 
package me.whiteship.designpatterns._01_creational_patterns._04_builder._02_after;

import me.whiteship.designpatterns._01_creational_patterns._04_builder._01_before.TourPlan;

import java.time.LocalDate;

public interface TourPlanBuilder {
		TourPlanBuilder newInstance();//이거 선언	
  
    TourPlanBuilder nightsAndDays(int nights, int days);

    TourPlanBuilder title(String title);

    TourPlanBuilder startDate(LocalDate localDate);

    TourPlanBuilder whereToStay(String whereToStay);

    TourPlanBuilder addPlan(int day, String plan);

    TourPlan getPlan();

}

https://github.com/3DPIT/study/blob/master/05.%EC%BD%94%EB%94%A9%EC%9C%BC%EB%A1%9C%ED%95%99%EC%8A%B5%ED%95%98%EB%8A%94GoF%EC%9D%98%EB%94%94%EC%9E%90%EC%9D%B8%ED%8C%A8%ED%84%B4/01.%EA%B0%9D%EC%B2%B4%EC%83%9D%EC%84%B1%EA%B4%80%EB%A0%A8%EB%94%94%EC%9E%90%EC%9D%B8%ED%8C%A8%ED%84%B4/2021/11/1129/%EB%B9%8C%EB%8D%94%ED%8C%A8%ED%84%B4/04.%EC%9E%90%EB%B0%94%EC%99%80%EC%8A%A4%ED%94%84%EB%A7%81%EC%97%90%EC%84%9C%EC%B0%BE%EC%95%84%EB%B3%B4%EB%8A%94%ED%8C%A8%ED%84%B4/2021.11.29_%EB%B9%8C%EB%8D%94%ED%8C%A8%ED%84%B404.%EC%9E%90%EB%B0%94%EC%99%80%EC%8A%A4%ED%94%84%EB%A7%81%EC%97%90%EC%84%9C%EC%B0%BE%EC%95%84%EB%B3%B4%EB%8A%94%ED%8C%A8%ED%84%B4.md