Add sealed module: modelling domains with sealed types and exhaustive switch

Payment model, permits and the three modifiers, default-branch trap, generic and recursive hierarchies, visitor comparison, run-time enforcement, modules. Transcripts from JDK 21, 25 and 27. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01TF9JWFvJSNm6HVzswzZU5a
2026-09-24 12:03:59 +00:00
parent 65a4bbbbe3
commit ff6130bede
38 changed files with 638 additions and 0 deletions
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+module demo.pay { }
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+package pay.api;
+public sealed interface Payment permits pay.impl.Card, pay.impl.Upi {}
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+package pay.app;
+import pay.api.Payment;
+import pay.impl.*;
+public class Main {
+    public static void main(String[] args) {
+        Payment p = new Card(100);
+        String s = switch (p) { case Card c -> "card"; case Upi u -> "upi"; };
+        System.out.println(s + " in module " + Payment.class.getModule().getName());
+    }
+}
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+package pay.impl;
+public record Card(long amount) implements pay.api.Payment {}
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+package pay.impl;
+public record Upi(long amount) implements pay.api.Payment {}