import java.util.ArrayList;

//Component Node, common interface
interface AbstractFile {
	public void ls();
}

// File implements the common interface, a Leaf
class File implements AbstractFile {
	private String m_name;
	public File(String name) {
		m_name = name;
	}
	public void ls() {
		System.out.println(CompositeDemo.g_indent + m_name);
	}
}

// Directory implements the common interface, a composite
class Directory implements AbstractFile {
	private String m_name;
	private ArrayList<AbstractFile> m_files = new ArrayList<AbstractFile>();
	public Directory(String name) {
		m_name = name;
	}
	public void add(AbstractFile obj) {
		m_files.add(obj);
	}
	public void ls() {
		System.out.println(CompositeDemo.g_indent + m_name);
		CompositeDemo.g_indent.append("   ");  // add 3 spaces
		for (int i = 0; i < m_files.size(); ++i) {
			AbstractFile obj = m_files.get(i);
			obj.ls();
		}
        //remove the 3 spaces:
		CompositeDemo.g_indent.setLength(CompositeDemo.g_indent.length() - 3);
	}
}

public class CompositeDemo {
	public static StringBuffer g_indent = new StringBuffer();

	public static void main(String[] args) {
		Directory one = new Directory("dir111"),
                  two = new Directory("dir222"),
                thr = new Directory("dir333");
		File a = new File("a"), b = new File("b"), c = new File("c"),
             d = new File("d"), e = new File("e");
		one.add(a);
		one.add(two);
		one.add(b);
		two.add(c);
		two.add(d);
		two.add(thr);
		thr.add(e);
		one.ls();
	}
}