Added PollState to have a wrapper instead of returning null

1 files changed, 13 insertions, 0 deletions

diff --git a/src/main/java/com/it_jaros/jscanner/PollState.java b/src/main/java/com/it_jaros/jscanner/PollState.java
new file mode 100644
index 0000000..474c055
--- /dev/null
+++ b/src/main/java/com/it_jaros/jscanner/PollState.java
@@ -0,0 +1,13 @@
+package com.it_jaros.jscanner;
+
+/**
+ * A sealed interface representing the three possible outcomes of a CompletionService
+ * poll operation: successful result, task failure, or not ready yet.
+ * Makes error handling explicit — Failure and Unavailable are distinct and compile-time
+ * required to handle via exhaustiveness checking in switch statements.
+ */
+public sealed interface PollState<T> {
+    record Success<T>(T value) implements PollState<T> {}
+    record Failure<T>(Throwable error) implements PollState<T> {}
+    record Unavailable<T>() implements PollState<T> {}
+}