Java中的unix ls命令

Question

Hi I am trying to list folders in unix "ls" command style in java. I have a folder tree like this :

My file structure is as follows :

private class Node{

    public List<Node> children= new ArrayList<Node>();
    public String value;
    public Node(String value){
        this.value = value;
    }

    public void addSubDirectory(Node child){
        children.add(child);
    }

}

Problem : I am not able to recurse more than the children of current folder when there is nothing after the ' * ' in a command

For eg. command

ls A/B/*/*/E/ and ls A/*/*/M/*/E/ works

But command " ls A/ * " only shows

BY

Code to traverse

public void showCommand(Node root, String command){
        String argument = command.substring(3);
        System.out.println("command is ls "+argument);
        show(root,argument);   
    }
    private void show(Node root, String cmd){

        int N = cmd.length();
        if(N==0){
            // case when end of command is reached
            for(Node child:root.children){
                System.out.println(child.value);
            }
        }else{
            char c = cmd.charAt(0);
            // case when folder name is present in command
            if((c!='*') && (c!='/')){
                for(Node child:root.children){
                    if(child.value.equals(String.valueOf(c))){
                        show(child,cmd.substring(1));
                    }
                }
                return;
            }else if(c=='*'){  
            // case when * is present in command
            // i think problem lies here
                if(N==1){
                   System.out.println(root.value);
                   preOrderTraverse(root);
                }else{
                  for(Node child:root.children){
                      show(child,cmd.substring(1));
                  }
                }
                return;
            }else if(c=='/'){
            // case when '/' is present in commmand
                show(root,cmd.substring(1));
                return;
            }

        }
    }

Answer 1

When the last char in the command is a *, you call back the showCommand method with an empty cmd and when the method receives an empty cmd string the recursion stops.

When the current char c is a *, you should check it's the last char in cmd , if it is then you should send the current cmd instead of cmd.substring(1) . That way it should go through the hierarchy recursively.