Use sealed classes where possible

Author: ascopes

java-compiler-testing/src/main/java/io/github/ascopes/jct/workspaces/impl/AbstractManagedDirectory.java

@@ -43,7 +43,9 @@
  * @author Ashley Scopes
  * @since 0.0.1
  */
-public abstract class AbstractManagedDirectory implements ManagedDirectory {
+public abstract sealed class AbstractManagedDirectory
+    implements ManagedDirectory
+    permits RamDirectoryImpl, TempDirectoryImpl {
 
   private final String name;
   private final Path rootDirectory;