#format java
/** 
 * VisitorPattern example
 */

import java.util.Iterator;
import java.util.Vector;

abstract class Visitor {
    public abstract void visit(File file);
    public abstract void visit(Directory directory);
}

interface Acceptor {
    public abstract void accept(Visitor v);
}

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() + ")";
    }
}

class File extends Entry {
    private String name;
    private int size;
    public File(String name, int size) {
        this.name = name;
        this.size = size;
    }
    public String getName() {
        return name;
    }
    public int getSize() {
        return size;
    }
    public void accept(Visitor v) {
        v.visit(this);
    }
}

class Directory extends Entry {
    private String name;
    private Vector dir = new Vector();
    public Directory(String name) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
    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();
    }
    public void accept(Visitor v) {
        v.visit(this);
    }
}

class ListVisitor extends Visitor {
    private String currentdir = "";
    public void visit(File file) {
        System.out.println(currentdir + "/" + file);
    }
    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;
    }
}

class FileTreatmentException extends RuntimeException {
    public FileTreatmentException() {
    }
    public FileTreatmentException(String msg) {
        super(msg);
    }
}

public class VisitorDirectory {
    public static void main(String[] args) {
        try {
            System.out.println("Making root entries...");
            Directory root = new Directory("root");
            Directory bin = new Directory("bin");
            Directory usr = new Directory("usr");
            root.add(bin);
            root.add(usr);
            bin.add(new File("vi",10000));
            bin.add(new File("latex",20000));
            root.accept(new ListVisitor());
        } catch(FileTreatmentException e) {
            e.printStackTrace();
        }
    }
}