gagdadagda

import java.util.ArrayList;
import java.util.List;


public class Directory extends Node {
    private List<INode> subElements;

    @Override
    public void accept(FSVisitor visitor) {
        visitor.visit(this);
        for (INode node : subElements)
            node.accept(visitor);
    }

    public Directory (String name, int id){
        super(name, id);
        this.subElements = new ArrayList<INode>();
    }

    public List<INode> getSubs(){
        return subElements;
    }

    public void add (INode newNode){
        newNode.setParent(this);
        subElements.add(newNode);
    }


    public void remove (int id){
        INode curNode = null;
        for (INode searchNode : subElements)
            if (searchNode.getId() == id){
                curNode = searchNode;
                break;
            }
        if (curNode != null)
            subElements.remove(curNode);
    }

    public String toString(){
        if (parent == null)
            return getName();
        return parent.getName() + getName() + "/";
    }

}

public class File extends Node implements INode {

    protected File(String name, int id) {
        super(name, id);
    }

    @Override
    public void accept(FSVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public String toString() {
        return parent.toString() + getName();
    }



}

public class FSException extends Exception {
    private String msg;

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    @Override
    public String getMessage() {
        // TODO Auto-generated method stub
        return msg;
    }

    public FSException(String msg){
        this.msg = msg;
    }

}
import java.util.List;


public class FSManager {
    private Directory root;

    private enum ElemType{
        FILE, DIRECTORY
    }

    private List<Directory> getPossibleDirs(int parentId){
        SearchVisitor searchVisitor = new SearchVisitor(parentId);
        root.accept(searchVisitor);
        return searchVisitor.getResults();
    }

    private void addElement(INode node, Directory parent){
        parent.add(node);
    }

    private void addElement(INode newElement, int parentId) throws FSException{
        List<Directory> possibleDirs = getPossibleDirs(parentId);
        for (Directory curDir : possibleDirs){
            if (checkUnique(newElement, curDir)){
                addElement(newElement, curDir);
                return;
            }
        }
        throw new FSException("No suitable directory");
    }

    private boolean checkUnique(INode node, Directory dir){
        for (INode curNode : dir.getSubs()){
            if (curNode.getId() == node.getId() || curNode.getName() == node.getName())
                return false;
        }
        return true;
    }

    private boolean exists(int id, Directory dir, ElemType elemType){
        for (INode curNode : dir.getSubs()){
            if (curNode.getId() == id && ((elemType == ElemType.FILE && curNode instanceof File) || (elemType == ElemType.DIRECTORY && curNode instanceof Directory)))
                return true;
        }
        return false;
    }

    private void removeElement(int id, int parentId, ElemType fileOrDir) throws FSException{
        List<Directory> possibleDirs = getPossibleDirs(parentId);
        for (Directory curDir : possibleDirs ){
            if (exists(id, curDir, fileOrDir)){
                curDir.remove(id);
                return;
            }
        }
        throw new FSException("No suitable directory");
    }

    public void addFolder(int id, String name, int parentId) throws FSException{
        Directory newDir = new Directory(name, id);
        addElement(newDir, parentId);
    }

    public void addFile(int id, String name, int parentId) throws FSException {
        File newFile = new File(name, id);
        addElement(newFile, parentId);
    }


    public void deleteFolder (int id, int parentId) throws FSException{
        removeElement(id, parentId, ElemType.DIRECTORY);
    }

    public void deleteFile (int id, int parentId) throws FSException{
        removeElement(id, parentId, ElemType.FILE);
    }


    public void printFS(){
        FSVisitor printer = new FSPrinter();
        root.accept(printer);
    }

    public FSManager(){
        root = new Directory("/", 0);
        root.setParent(null);
    }


}

public class FSPrinter implements FSVisitor {

    @Override
    public void visit(Directory dir) {
        System.out.println(dir);
    }

    @Override
    public void visit(File file) {
        System.out.println(file);
    }

}

public interface FSVisitor {
    void visit(Directory dir);
    void visit (File file);
}

public interface INode {
    int getId();
    String getName();
    void accept(FSVisitor visitor);
    void setParent (Directory dir);
}

public abstract class Node implements INode {
    private int id;
    private String name;
    protected Directory parent;

    @Override
    public int getId() {
        return id;
    }

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

    protected Node(String name, int id){
        this.id = id;
        this.name = name;
    }

    public void setParent(Directory p){
        parent = p;
    }

}
import java.util.ArrayList;
import java.util.List;


public class SearchVisitor implements FSVisitor {
    private int parentId;
    private List<Directory> results;

    public SearchVisitor(int parentId) {
        this.parentId = parentId;
        results = new ArrayList<Directory>();
    }

    @Override
    public void visit(Directory dir) {
        if (dir.getId() == parentId)
            results.add(dir);
    }

    @Override
    public void visit(File file) {
        // TODO Auto-generated method stub
    }

    public List<Directory> getResults(){
        return results;
    }

}

public class Tester {

    /**
     * @param args
     */
    public static void main(String[] args) {
        FSManager fs = new FSManager();

        try {
            fs.addFolder(1, "usr", 0);
            fs.addFolder(2, "etc", 0);
            fs.addFile(3, "va", 0);
            fs.addFile(1, "usrs", 1);
            fs.addFile(2, "usrs2", 1);
            fs.printFS();
            fs.deleteFile(2, 1);
            fs.deleteFolder(1, 0);
            fs.printFS();
        } catch (FSException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}