File System using composite pattern

Question

I'm trying to build a File system such that contains the following classes: FileSystem, Directory, File.
My code is:

public class FileSystem {
    private List<Directory> ld;
    public FileSystem() {
        ld = new ArrayList<Directory>();
    }
    public void addDirectory(Directory dir) {
        ld.add(dir);
    }
    public void showAll() {
        for (Directory directory : ld) {
            directory.showAll();
        }
    }
}

public class File {
    private String fileName;

    public File(String fileName) {
        this.fileName = fileName;
    }
    public String getName() {
        return fileName;
    }
    public void setName(String name) {
        this.fileName = fileName;
    }
}

public class Directory {
    private String directoryName;
    private List<File> files;
    private List<Directory> subDirs;

    public Directory(String directoryName) {
        this.directoryName = directoryName;
        files = new ArrayList<File>();
        subDirs = new ArrayList<Directory>();
    }
    public String getName() {
        return this.directoryName;
    }
    public void setName(String name) {
        this.directoryName = name;
    }
    // Add and remove files
    public void addFile(File file) {
        files.add(file);
    }
    public void removeFile(File file) {
        files.remove(file);
    }
    // Add and remove directories
    public void addDirectory(Directory dir) {
        subDirs.add(dir);
    }
    public void removeDirectory(Directory dir) {
        subDirs.remove(dir);
    }

    public void showAll() {
        System.out.println(this.directoryName);
        for (File f : files) {
            System.out.println("    " + f.getName());
        }
    }
}

public class Create {
    public static void main(String[] args) {
        FileSystem fs = new FileSystem();
        Directory d1 = new Directory("Directory1");

        d1.addFile(new File("FileX"));
        Directory d11 = new Directory("Directory11");
        d11.addFile(new File("File1"));
        d11.addFile(new File("File2"));
        d1.addDirectory(d11);

        fs.addDirectory(d1);
        fs.showAll();
    }
}

But when I try to print all the content using the method showAll it prints only 'Directory1' and 'FileX', but I want to print:
Directory1
FileX
Directory11
File1
File2

I wouldn't use FileSystem as a separate entity. At least from your example it can be just a Directory with the name defining some root like '/'. — Alexey R.
– Alexey R., Commented Sep 1, 2022 at 7:57
Regarding your question you should use recursion so that you first check if you have any folders and if yes, call showAll for all of them, and if not, traverse through files. — Alexey R.
– Alexey R., Commented Sep 1, 2022 at 7:59

Alexey R. · Accepted Answer · 2022-09-01 08:36:49Z

1

Your Directory#showAll should look like this:

public void showAll() {
    System.out.println(this.directoryName);
    for (File f : files) {
        System.out.println("    " + f.getName());
    }
    for(Directory subDir: subDirs){
        subDir.showAll();
    }
}

So it traverses recursively through subDirs also.

P.S. - I would also get rid of FileSystem entity or at least introduce parent-child relationship between Directory and FileSystem

edited Sep 1, 2022 at 8:36

answered Sep 1, 2022 at 8:05

Alexey R.

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1 Comment

Xavi Over a year ago

Now it shows me: Directory11 ` File1` ` File2` Directory1 ` FileX` And I want: Directory1 ` FileX` ` Directory11` ` File1` ` File2` Such that Directory11 is a sub directory of Directory1

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