Compositeパターン

再帰。

% find . -name "*.java" -print0 |xargs -0 cat                                []
import java.util.ArrayList;
import java.util.List;

public class Directory extends Entory {
	private String name;
	private List<Entory> directory = new ArrayList<Entory>();

	public Directory(String name) {
		this.name = name;
	}

	@Override
	public String getName() {
		return name;
	}

	@Override
	public int getSize() {
		int size = 0;
		for (Entory entry : directory) {
			size += entry.getSize();
		}
		return size;
	}

	@Override
	public Entory add(Entory entory) {
		directory.add(entory);
		entory.parent = this;
		return this;
	}

	@Override
	protected void printLine(String prefix) {
		System.out.println(prefix + "/" + this);
		for (Entory entory : directory) {
			entory.printLine(prefix + "/" + name);
		}
	}

}
public abstract class Entory {
	protected Entory parent;

	public abstract String getName();

	public abstract int getSize();

	public Entory add(Entory entry) throws Exception {
		throw new Exception("");
	}

	public void printLine() {
		printLine("");
	}

	protected abstract void printLine(String prefix);

	@Override
	public String toString() {
		return getName() + "(" + getSize() + ")";
	}

	public String getFullPath() {
		StringBuffer sb = new StringBuffer();
		Entory entory = this;
		do {
			sb.insert(0, "/" + entory.getName());
			entory = entory.parent;
		} while (entory != null);
		return sb.toString();
	}
}
public class File extends Entory {
	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
	protected void printLine(String prefix) {
		System.out.println(prefix + "/" + this.toString());
	}

}
public class Main {

	public static void main(String... args) throws Exception {
		Entory rootdir = new Directory("root");
		Entory bindir = new Directory("bin");
		Entory tmpdir = new Directory("tmp");
		Entory usrdir = new Directory("usr");
		Entory hanadir = new Directory("hanako");
		rootdir.add(bindir);
		rootdir.add(tmpdir);
		rootdir.add(usrdir);
		usrdir.add(hanadir);
		bindir.add(new File("vi", 10000));
		bindir.add(new File("emacs", 12000));
		tmpdir.add(new File("tmp.txt", 300));
		tmpdir.add(new File("hoge.txt", 3));
		Entory superfile = new File("superfile.txt", 330);
		hanadir.add(superfile);
		rootdir.printLine();
		System.out.println(superfile.getFullPath());
	}
}

/root(22633)
/root/bin(22000)
/root/bin/vi(10000)
/root/bin/emacs(12000)
/root/tmp(303)
/root/tmp/tmp.txt(300)
/root/tmp/hoge.txt(3)
/root/usr(330)
/root/usr/hanako(330)
/root/usr/hanako/superfile.txt(330)
/root/usr/hanako/superfile.txt