Core Classes

You will have to deal with absolute and relative (e.g. ../../Desktop/var.png) filename specifications.

You will have to deal with files having no extensions like e.g. /usr/bin/firefox. In this case the extension attribute is expected to be null rather than "".

For the sake of limiting complexity do not consider filenames starting with a period (like /home/heinz/.bashrc) or containing multiple periods like ../arrow.right.png.

To distinguish the above mentioned system defaults for filename path conventions read the java.lang.System section of chapter 5 along with its API. The table of system properties in [Kurniawan] will enable your implementation to work both on Windows and non-Windows systems accordingly.

Read Java File Separator vs File Path Separator.

You will have to parse filenames like "/usr/share/openvpn/hdm.conf". Exercise 7 from the “Quiz” section of chapter 5 in [Kurniawan] shows an example dissecting a string containing tokens being separated by space characters using the java.util.StringTokenizer class. Read its documentation and learn how to specify string delimiters other than default space ' '. It'll allow you to dissect paths using separators '/' (Unix) or '\' (Windows) to break paths into components.

Likewise you may split filenames into basename / extension by using '.' as separator.

Assembling path components may be effected by either using a StringBuffer or a StringJoiner instance. Mind the distinction between relative and absolute paths!

The methods indexOf(...) and substring(...) come in handy when dissecting filenames into basename and extension.

The backslash “\” must be escaped when being part of a Java™ String literal:

   String path = "C:\\programms\\openvpn\\conf\\hdm.ovpn";

Unit tests may be written for Windows and non-Windows systems separately. Read https://www.thekua.com/atwork/2008/09/running-tests-on-a-specific-os-under-junit4 how to use Assume.assumeFalse() / Assume.assumeTrue(...) to separate Windows from Unix tests.

Test your implementation both on Windows and Unix-type platforms. The following tests may be used as a starting point:

public class MetaInfoUnixTest {

   static private final boolean isWindows =
             System.getProperty("os.name").startsWith("Windows");

   @Test
   public void testAbsoluteWithoutExtension() {
       Assume.assumeFalse(isWindows);

       final FileMetaInfo fmi = new FileMetaInfo("/usr/openvpn/hdm");

       Assert.assertFalse(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("/usr/openvpn", fmi.path);
       Assert.assertEquals("hdm", fmi.basename);
       Assert.assertEquals(null, fmi.extension);
   }

   @Test
   public void testAbsoluteWithExtension() {
       Assume.assumeFalse(isWindows);

       final FileMetaInfo fmi = new FileMetaInfo("/usr/openvpn/hdm.conf");

       Assert.assertFalse(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("/usr/openvpn", fmi.path);
       Assert.assertEquals("hdm", fmi.basename);
       Assert.assertEquals("conf", fmi.extension);
   }

   @Test
   public void testRelativeWithoutExtension() {
       Assume.assumeFalse(isWindows);

       final FileMetaInfo fmi = new FileMetaInfo("../Desktop/icon");

       Assert.assertTrue(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("../Desktop", fmi.path);
       Assert.assertEquals("icon", fmi.basename);
       Assert.assertEquals(null, fmi.extension);
   }

   @Test
   public void testRelativeWithExtension() {
       Assume.assumeFalse(isWindows);

       final FileMetaInfo fmi = new FileMetaInfo("../../Desktop/icon.gif");

       Assert.assertTrue(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("../../Desktop", fmi.path);
       Assert.assertEquals("icon", fmi.basename);
       Assert.assertEquals("gif", fmi.extension);
   }
}

public class MetaInfoWindowsTest {

   static private final boolean isWindows =
                    System.getProperty("os.name").startsWith("Windows");

   @Test
   public void testAbsoluteWithoutExtension() {
     Assume.assumeTrue(isWindows);

     final FileMetaInfo fmi =
          new FileMetaInfo("F:\\software\\my\\archive");

     Assert.assertFalse(fmi.isRelative);
     Assert.assertEquals('F', fmi.drive);
     Assert.assertEquals("\\software\\my", fmi.path);
     Assert.assertEquals("archive", fmi.basename);
     Assert.assertEquals(null, fmi.extension);
   }

   @Test
   public void testAbsoluteWithExtension() {
       Assume.assumeTrue(isWindows);

       final FileMetaInfo fmi =
           new FileMetaInfo("F:\\subdir\\archive.zip");

       Assert.assertFalse(fmi.isRelative);
       Assert.assertEquals('F', fmi.drive);
       Assert.assertEquals("\\subdir", fmi.path);
       Assert.assertEquals("archive", fmi.basename);
       Assert.assertEquals("zip", fmi.extension);
   }

   @Test
   public void testRelativeWithoutExtension() {
       Assume.assumeTrue(isWindows);

       final FileMetaInfo fmi = new FileMetaInfo("..\\Desktop\\icon");

       Assert.assertTrue(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("..\\Desktop", fmi.path);
       Assert.assertEquals("icon", fmi.basename);
       Assert.assertEquals(null, fmi.extension);
   }

   @Test
   public void testRelativeWithExtension() {
       Assume.assumeTrue(isWindows);

       final FileMetaInfo fmi =
           new FileMetaInfo("..\\..\\Desktop\\icon.gif");

       Assert.assertTrue(fmi.isRelative);
       Assert.assertEquals(FileMetaInfo.noDrive, fmi.drive);
       Assert.assertEquals("..\\..\\Desktop", fmi.path);
       Assert.assertEquals("icon", fmi.basename);
       Assert.assertEquals("gif", fmi.extension);
   }
}