Avoid Public Event publisher

community/knowledge/events/declare-event-publishers-local-or-internal.good.al

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+// Demonstration only. Shows the correct pattern: a public facade codeunit whose event publishers
+// are internal, so only the implementation codeunit decides when they fire.
+
+codeunit 50100 "Loyalty Points Mgt Good"
+{
+    procedure AwardPoints(CustomerNo: Code[20]; SalesAmount: Decimal)
+    var
+        LoyaltyPointsImpl: Codeunit "Loyalty Points Impl Good";
+    begin
+        LoyaltyPointsImpl.AwardPoints(CustomerNo, SalesAmount);
+    end;
+
+    // internal, not public: the implementation codeunit raises this and nobody else. Subscribers
+    // bind through Codeunit::"Loyalty Points Mgt Good", which is public by default - that object
+    // access is all a subscriber in another extension needs.
+    [IntegrationEvent(false, false)]
+    internal procedure OnBeforeAwardPoints(CustomerNo: Code[20]; var Points: Decimal; var IsHandled: Boolean)
+    begin
+    end;
+
+    [IntegrationEvent(false, false)]
+    internal procedure OnAfterAwardPoints(CustomerNo: Code[20]; Points: Decimal)
+    begin
+    end;
+}
+
+codeunit 50101 "Loyalty Points Impl Good"
+{
+    Access = Internal;
+
+    procedure AwardPoints(CustomerNo: Code[20]; SalesAmount: Decimal)
+    var
+        LoyaltyPointsMgt: Codeunit "Loyalty Points Mgt Good";
+        Points: Decimal;
+        IsHandled: Boolean;
+    begin
+        Points := SalesAmount / 10;
+
+        IsHandled := false;
+        LoyaltyPointsMgt.OnBeforeAwardPoints(CustomerNo, Points, IsHandled);
+        if IsHandled then
+            exit;
+
+        // ... insert the loyalty entry ...
+
+        LoyaltyPointsMgt.OnAfterAwardPoints(CustomerNo, Points);
+    end;
+}
+
+codeunit 50102 "Loyalty Points Sub Good"
+{
+    // The shape a subscriber in a dependent extension takes: it names the public object, and is
+    // indifferent to the publisher being internal.
+    [EventSubscriber(ObjectType::Codeunit, Codeunit::"Loyalty Points Mgt Good", 'OnAfterAwardPoints', '', false, false)]
+    local procedure LogAwardedPointsOnAfterAwardPoints(CustomerNo: Code[20]; Points: Decimal)
+    begin
+        // ... write telemetry ...
+    end;
+}