[DesignPattern - Visitor] sample1

Design Pattern - Visitor

1. 클래스다이어그램

2. Source

• Visitor.java

  package com.dazzilove.visitor.sample1;
  
  public abstract class Visitor {
      public abstract void visit(File file);
      public abstract void visit(Directory directory);
  }

• Acceptor.java

  package com.dazzilove.visitor.sample1;
  
  public interface Acceptor {
      public abstract void accept(Visitor v);
  }

• Entry.java

  package com.dazzilove.visitor.sample1;
  
  import java.util.Iterator;
  
  public abstract class Entry implements Acceptor {
      public abstract String getName();
      public abstract int getSize();
      public Entry add(Entry entry) throws FileTreatmentException {
          throw new FileTreatmentException();
      }
      public Iterator iterator() throws FileTreatmentException {
          throw new FileTreatmentException();
      }
      public String toString() {
          return getName() + " (" + getSize() + ")";
      }
  }

• File.java

  package com.dazzilove.visitor.sample1;
  
  public class File extends Entry {
      private String name;
      private int size;
      
      public File(String name, int size) {
          this.name = name;
          this.size = size;
      }
  
      @Override
      public String getName() {
          return name;
      }
  
      @Override
      public int getSize() {
          return size;
      }
  
      @Override
      public void accept(Visitor v) {
          v.visit(this);
      }
  }

• Directory.java

  package com.dazzilove.visitor.sample1;
  
  import java.util.Iterator;
  import java.util.Vector;
  
  public class Directory extends Entry {
      private String name;
      private Vector dir = new Vector();
      
      public Directory(String name) {
          this.name = name;
      }
  
      @Override
      public String getName() {
          return name;
      }
  
      @Override
      public int getSize() {
          int size = 0;
          Iterator it = dir.iterator();
          while(it.hasNext()) {
              Entry entry = (Entry)it.next();
              size += entry.getSize();
          }
          return size;
      }
      
      public Entry add(Entry entry) {
          dir.add(entry);
          return this;
      }
  
      public Iterator iterator() {
          return dir.iterator();
      }
      
      @Override
      public void accept(Visitor v) {
          v.visit(this);
      }
  }

• ListVisitor.java

  package com.dazzilove.visitor.sample1;
  
  import java.util.Iterator;
  
  public class ListVisitor extends Visitor {
      private String currentDir = "";
      
      @Override
      public void visit(File file) {
          System.out.println(currentDir + "/" + file);
      }
  
      @Override
      public void visit(Directory directory) {
          System.out.println(currentDir + "/" + directory);
          String saveDir = currentDir;
          currentDir = currentDir + "/" + directory.getName();
          Iterator it = directory.iterator();
          while(it.hasNext()) {
              Entry entry = (Entry)it.next();
              entry.accept(this);
          }
          currentDir = saveDir;
      }
  }

• FileTreatmentException.java

  package com.dazzilove.visitor.sample1;
  
  public class FileTreatmentException extends RuntimeException {
      public FileTreatmentException() {
      }
      public FileTreatmentException(String msg) {
          super(msg);
      }
  }

• Main.java

  package com.dazzilove.visitor.sample1;
  
  public class Main {
      public static void main(String[] args) {
          try {
              System.out.println("Making root entries...");
              Directory rootDir = new Directory("root");
              Directory binDir = new Directory("bin");
              Directory tmpDir = new Directory("tmp");
              Directory usrDir = new Directory("usr");
              rootDir.add(binDir);
              rootDir.add(tmpDir);
              rootDir.add(usrDir);
              binDir.add(new File("vi", 1000));
              binDir.add(new File("latex", 2000));
              rootDir.accept(new ListVisitor());
              
              System.out.println("");
              System.out.println("Making user entries...");
              Directory kim = new Directory("kim");
              Directory lee = new Directory("lee");
              Directory kang = new Directory("kang");
              usrDir.add(kim);
              usrDir.add(lee);
              usrDir.add(kang);
              kim.add(new File("diary.html", 100));
              kim.add(new File("composite.java", 200));
              lee.add(new File("memo.txt", 300));
              kang.add(new File("game.doc", 400));
              kang.add(new File("junk.mail", 500));
              rootDir.accept(new ListVisitor());
          } catch (FileTreatmentException e) {
              e.printStackTrace();
          }
      }
  }

3. 결과출력