20: More refresher logic

src/main/tjava/com/r35157/jupiterperpsalarm/impl/ref/JupiterPerpsEntryPriceVariableRefreshWatcher.tjava

@@ -1,7 +1,13 @@
 package com.r35157.jupiterperpsalarm.impl.ref;
 
-import java.nio.file.Path;
+import java.nio.file.*;
 import java.util.Objects;
+import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.StandardWatchEventKinds;
+import java.nio.file.WatchEvent;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
 
 public final class JupiterPerpsEntryPriceVariableRefreshWatcher {
 
@@ -24,10 +30,43 @@ public final class JupiterPerpsEntryPriceVariableRefreshWatcher {
     }
 
     private void run() {
-        System.out.println(
+        try (WatchService watchService = FileSystems.getDefault().newWatchService()) {
-                "Jupiter Perps entry price variable refresh watcher started for directory: "
+
-                        + confDirectory
+            confDirectory.register(
-        );
+                    watchService,
+                    StandardWatchEventKinds.ENTRY_CREATE
+            );
+
+            System.out.println(
+                    "Jupiter Perps entry price variable refresh watcher started for directory: "
+                            + confDirectory
+            );
+            while (true) {
+                WatchKey key = watchService.take();
+
+                for (WatchEvent<?> event : key.pollEvents()) {
+                    System.out.println("WatchService event: " + event.context());
+                }
+
+                if (!key.reset()) {
+                    System.err.println(
+                            "Jupiter Perps entry price variable refresh watcher stopped: watch key is no longer valid"
+                    );
+                    return;
+                }
+            }
+        } catch (IOException exception) {
+            System.err.println(
+                    "Could not start Jupiter Perps entry price variable refresh watcher: "
+                            + exception.getMessage()
+            );
+        } catch (InterruptedException exception) {
+            Thread.currentThread().interrupt();
+
+            System.err.println(
+                    "Jupiter Perps entry price variable refresh watcher interrupted"
+            );
+        }
     }
 
     private static final String REFRESH_TRIGGER_FILE_NAME =