added splitExtension function

src/main/java/net/woggioni/jwo/JWO.java

@@ -2,6 +2,7 @@ package net.woggioni.jwo;
 
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
+import net.woggioni.jwo.tuple.Tuple2;
 
 import javax.net.ssl.*;
 import java.io.*;
@@ -214,9 +215,9 @@ public class JWO {
      *
      * @param list the input list
      * @param <T>  the type parameter of the {@link List}
+     * @return the input list
      * @throws IndexOutOfBoundsException     if the list is empty
      * @throws UnsupportedOperationException if the remove operation is not supported by this list
-     * @return the input list
      */
     public static <T> T pop(List<T> list) {
         return list.remove(list.size() - 1);
@@ -360,4 +361,15 @@ public class JWO {
                 .filter(Files::isExecutable)
                 .findFirst();
     }
+
+    public static Optional<Tuple2<String, String>> splitExtension(Path file) {
+        String fileName = file.getFileName().toString();
+        int index = fileName.lastIndexOf('.');
+        if (index == -1) {
+            return Optional.empty();
+        } else {
+            return Optional.of(
+                    new Tuple2<>(fileName.substring(0, index), fileName.substring(index)));
+        }
+    }
 }