22-04-11-비지터패턴-4부-자바와스프링에서찾아보는패턴

01.방문자패턴 적용 사례

01.1 자바

• FileVisitor, SimpleFileVisitor
• AnnotationValueVisitor
• ElementVisitor

package me.whiteship.designpatterns._03_behavioral_patterns._23_visitor._03_java;

import me.whiteship.designpatterns._03_behavioral_patterns._23_visitor._02_after.Triangle;

import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;

public class SearchFileVisitor implements FileVisitor<Path> {

    private String fileToSearch;
    private Path startingDirectory;

    public SearchFileVisitor(String fileToSearch, Path startingDirectory) {
        this.fileToSearch = fileToSearch;
        this.startingDirectory = startingDirectory;
    }

    @Override
    public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
        if (fileToSearch.equals(file.getFileName().toString())) {
            System.out.println("found " + file.getFileName());
            return FileVisitResult.TERMINATE;
        }
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
        exc.printStackTrace(System.out);
        return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
        if (Files.isSameFile(startingDirectory, dir)) {
            System.out.println("search end");
            return FileVisitResult.TERMINATE;
        }
        return FileVisitResult.CONTINUE;
    }
}

package me.whiteship.designpatterns._03_behavioral_patterns._23_visitor._03_java;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;

public class VisitorInJava {

    public static void main(String[] args) throws IOException {
        Path startingDirectory = Path.of("/Users/keesun/workspace/design-patterns");
        SearchFileVisitor searchFileVisitor =
                new SearchFileVisitor("Triangle.java", startingDirectory);
        Files.walkFileTree(startingDirectory, searchFileVisitor);
    }
}

01.2 스프링

• BeanDefinitionVisitor

• package me.whiteship.designpatterns._03_behavioral_patterns._23_visitor._03_java;
  
  import org.springframework.beans.factory.config.BeanDefinitionVisitor;
  
  public class VisitorInSpring {
  
      public static void main(String[] args) {
          BeanDefinitionVisitor beanDefinitionVisitor;
      }
  }

   
• 거의 쓸일은 없음

https://3dpit.github.io/posts/%EB%B9%84%EC%A7%80%ED%84%B0%ED%8C%A8%ED%84%B4-4%EB%B6%80-%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/

22-04-11-비지터패턴-4부-자바와스프링에서찾아보는패턴