2021.12.11_데코레이터패턴02.패턴적용하기

CommentService

public interface CommentService
{
 void addComment(String comment);   
}

• 코멘트를 추가한 인터페이스 하나 추가

DefaultCommentService

public class DefaultCommentService implement CommentService{
    @Override
    public void addComment(String comment){
        System.out.println(comment);
    }
}

CommentDecorator

public class CommentDecorator implements CommentService{
	private CommentService commentService;
    
    public CommentDecorator(CommentService commentService){
        this.CommentService = commentService;
    }
    
    @Override
    public void addComment(String comment){
        commentService.addComment(comment);
    }
}

• 감싸는 데코레이터 생성

TrimmingCommentDecorator

public class TrimmingCommentDecorator extends CommentDecoorator{
	public TrimmingCommentDecorator(CommentService commentService){
		super(commentService);
    }
    
    @Override
    public void addComment(String comment){
        super.addComment(trim(comment));
    }
    
    private String trim(String comment){
		return comment.replace("...", "");
    }
}

SpanFilteringCommentDecorator

public class SpanFilteringCommentDecorator extends CommentDecorator{
    
    public SpanFilteringCommentDevorator(CommentService commentService){
        super.(commentService)
    }
    
    @Override
    public void addComment(String comment){
        if(isNotSpan(comment)){
           super.addComment(comment);
        }
    }
    
    private boolean isNotSpan(String comment){
        return !comment.contains("http");
    }
}

Client

public class Client{
    private CommentService commentService{
        this.CommentService = commentService;
    }
    
    public void writeComment(String comment){
		commentService.addComment(comment);
    }
}

App

public class App {

    private static boolean enabledSpamFilter = true;

    private static boolean enabledTrimming = true;

    public static void main(String[] args) {
        CommentService commentService = new DefaultCommentService();

        if (enabledSpamFilter) {
            commentService = new SpamFilteringCommentDecorator(commentService);
        }

        if (enabledTrimming) {
            commentService = new TrimmingCommentDecorator(commentService);
        }

        Client client = new Client(commentService);
        client.writeComment("오징어게임");
        client.writeComment("보는게 하는거 보다 재밌을 수가 없지...");
        client.writeComment("http://whiteship.me");
    }
}

• 이렇게 DefaultCommentService로만 받지만 여러 기능을 추가 할 수 있음
• 기능 구현이 추가 될때 좀 유용하게 쓸 수 있음
• 상속과의 다른점은 현재는 두개 의 기능이 있는데 내가 두개의 기능을 다 검사하고 싶을때
  • 상속의 경우는 통합된 한개를 더 만들어야하지만
  • 데코레이터를 이용하면 그렇게 하지 않아도 가능함

 

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%B4/02.%EA%B5%AC%EC%A1%B0%EA%B4%80%EB%A0%A8%EB%94%94%EC%9E%90%EC%9D%B8%ED%8C%A8%ED%84%B4/%EB%8D%B0%EC%BD%94%EB%A0%88%EC%9D%B4%ED%84%B0%ED%8C%A8%ED%84%B4/2021/1211/02.%ED%8C%A8%ED%84%B4%EC%A0%81%EC%9A%A9%ED%95%98%EA%B8%B0/2021.12.11_%EB%8D%B0%EC%BD%94%EB%A0%88%EC%9D%B4%ED%84%B0%ED%8C%A8%ED%84%B402.%ED%8C%A8%ED%84%B4%EC%A0%81%EC%9A%A9%ED%95%98%EA%B8%B0.md