import java.nio.file.Path;
import java.nio.file.Paths;

public class FilePaths {
    public static void main(String[] args) {
        // The Paths.get() method should be used to construct paths in a
        // portable way. It takes any number of arguments
        // and constructs a hierarchical path from them.
        Path p = Paths.get("dir1", "dir2", "filename");
        System.out.println("p: " + p);

        // You should always use Paths.get() instead of
        // concatenating / or \ manually. In addition
        // to providing portability, Paths.get() will also
        // normalize paths by removing superfluous separators
        // and directory changes.
        System.out.println(Paths.get("dir1//", "filename"));
        System.out.println(Paths.get("dir1/../dir1", "filename"));

        // getParent() and getFileName() can be used to split a path to the
        // directory and the file.
        System.out.println("p.getParent(): " + p.getParent());
        System.out.println("p.getFileName(): " + p.getFileName());

        // We can check whether a path is absolute.
        System.out.println(Paths.get("dir/file").isAbsolute());
        System.out.println(Paths.get("/dir/file").isAbsolute());

        String filename = "config.json";

        // Some file names have extensions following a dot. We
        // can get the extension out of such names with getExtension().
        String ext = getExtension(filename);
        System.out.println(ext);

        // To find the file's name with the extension removed,
        // use removeExtension().
        System.out.println(removeExtension(filename));

        // relativize() finds a relative path between a base and a
        // target. It returns a Path that can be used to construct
        // the target path from the base path.
        Path base = Paths.get("a/b");
        Path target = Paths.get("a/b/t/file");
        System.out.println(base.relativize(target));

        target = Paths.get("a/c/t/file");
        System.out.println(base.relativize(target));
    }

    private static String getExtension(String filename) {
        int dotIndex = filename.lastIndexOf('.');
        return (dotIndex == -1) ? "" : filename.substring(dotIndex);
    }

    private static String removeExtension(String filename) {
        int dotIndex = filename.lastIndexOf('.');
        return (dotIndex == -1) ? filename : filename.substring(0, dotIndex);
    }
}