Thread: Emulating a filesystem in Java for configuration managment?

Hi there,

I am looking for a way to emulate a filesystem in Java to manage my configuration. The program has a readline library that I am using to provide a primitive shell for interaction.

Originally I was trying to do something with hashmaps but that did not go so well since java would not let me use the <?> generic everywhere. So my idea has shifted more to using the FileSystemProvider class to create a fake filesystem that I can store the config inside of. But due to the lack of tutorials / examples I am unable to figure out the URI for a RAM based filesystem. All the examples I have seen are for ZIP based filesystems. The other problem is I want the filesystem to use fake files kinda like pointers to variables or method in my class files rather than actual files in a folder. Can this be done?

The entire configuration will be saved out to an XML file. I want to use the filesystem just as a means of providing an interface for editing the config.

Can anyone give me some insight on this?

Thanks!

The interface to the filesystem would be shell prompt created by a readline (specifically JLine2 for now) library.

As far as Sequential or Random writes, I am not sure if this applies. I am not actually trying to make a full blown FS. I am trying to create a pseudo filesystem that will be used to represent the configuration values in my program. In a similar way to how SysFS is to the Linux kernel.

The initial methods would be simple. For example I have a method that adds a new server to the root of my configuration the method is called from the configFS.addServer(). There is also an opposite to that method which will remove a server from the config. From within each server there is separate config values for things like setIPaddress() and setSSHportNumber.

How this relates to the filesystem is I want the various parts of the structure to be built as the methods are called. So for example when a new server is called I want a fake directory to be created that the player could "cd" into and modify the various default values for the server. The set methods would be more related to changing values of the fake files. For example if I have a "file" that controls which ssh port to use for the connection I want the method to simply change an int which would reflect the port number.

Yes a file would contain a value. Lets say the file is called "port" and it lives in "/server01/ssh/port". To change it would require using a command like "set port 22" which would change value of the ssh port number to 22 while you are sitting in the ssh directory. Follow me?

As far as attributes I was thinking about that. At the moment I don't see a reason to add attributes because this is a just a representation of the config. All I could say about that right now is maybe later.

When you ask "why the need for a new one?" I don't quite follow. The entire FS would just be the representation of an XML config file. The FS structure is make the config easier to work with so as to prevent errors by the user.

I had considered the idea of making an actual filesystem contained inside a directory that would be considered root but I thought it would make to many files that don't really need to be there.

Ok... this question has veered off of my original point of asking it.

The problem is I don't really have any methods to use as examples because as my plan goes I need a structure to hold my data before I build the methods to work on the data.

What I am trying to really determine is if an actual filesystem in memory is the right direction or not. Since my entire configuration will be stored inside of an XML file.

I also completely screwed up asking the first question correctly in the first place. What I REALLY MEANT to ask was more in concept to how I could emulate a directory structure in Java. The reason I kept throwing around filesystem in because I was going to use that package initally to implement the structure, later realizing that I could get creative with some maps and such I am pretty sure.

Not really...

The issue I am having is trying to figure out the best way to create the tree. Originally I was going to use the HashMap class for the root tree use the generics <String, ?> which would allow me to make the value almost anything. This would allow me to make something that resembles a directory tree. The problem I am running into is when I got one level down. Eclipse says it cannot instansiate a second instance of HashMap <String, ?> which would resemble the contents of a directory that is sitting at root.

import java.util.HashMap;
import java.util.Map;
 
 
public class Example {
 
	private Map <String, ?> config;
 
	public Example() {
 
		// This will initialize a new configuration on construction.
		config = new HashMap <> ();
 
	}
 
	public void add_directory(String par1) {
 
		config.put(par1, new HashMap <String, ?> ());
 
	}
 
}

No I did not. That might work let me try.

This may sound vague but what is considered and object? pretty much everything right? or are thing like char not objects?

--- Update ---

Yep that allowed me to instantiate a hashmap with in a hashmap without an error.