From 7c279747beb43c7e88633a6228a155a30e6834f7 Mon Sep 17 00:00:00 2001
From: Benjamin Culkin <scorpress@gmail.com>
Date: Mon, 27 May 2024 11:38:33 -0400
Subject: Initial import

---
 .../israfil/foundation/valuemodel/Vetoable.java    | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 israfil-foundation-valuemodel/src/main/java/net/israfil/foundation/valuemodel/Vetoable.java

(limited to 'israfil-foundation-valuemodel/src/main/java/net/israfil/foundation/valuemodel/Vetoable.java')

diff --git a/israfil-foundation-valuemodel/src/main/java/net/israfil/foundation/valuemodel/Vetoable.java b/israfil-foundation-valuemodel/src/main/java/net/israfil/foundation/valuemodel/Vetoable.java
new file mode 100644
index 0000000..5369287
--- /dev/null
+++ b/israfil-foundation-valuemodel/src/main/java/net/israfil/foundation/valuemodel/Vetoable.java
@@ -0,0 +1,44 @@
+/* 
+ * Copyright (c) 2003-2007 Israfil Consulting Services Corporation
+ * Copyright (c) 2003-2007 Christian Edward Gruber
+ * All Rights Reserved
+ *
+ * $Id: Types.java 129 2006-12-31 23:20:02Z cgruber $
+ */
+package net.israfil.foundation.valuemodel;
+
+/**
+ * An interface for objects that can notify observers of changes to itself 
+ * before the change.  The objects thus notified can veto the change.  The
+ * specific behaviour for vetoing is undefined and is dependent upon the
+ * particular implementation of the vetoable object and its vetoers.
+ * The changing object should call the provided callback signature, with the 
+ * parameter being the object that was changed in its new state. The vetoer
+ * is responsible for knowing what it needs to know in order to validate or
+ * veto the change.
+ * 
+ * Using a dynamic selector rather than a strong interface allows code
+ * to be notified of the change even if it was not constructed with the 
+ * notification interface, though it does need to match the signature.
+ * 
+ * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber</a>
+ * @author Latest: $Author: cgruber $
+ * @version $Revision: 129 $
+ */
+public interface Vetoable {
+    
+    /** Add one or more vetoers to this object, with a callback method spec 
+     * that will be invoked upon a data change.  The callback method should 
+     * contain three parameters.  The first is the notification source (the 
+     * holder or whatever), the second the old value, and the third the new 
+     * value. It also should return a boolean approving the change (or
+     * returning false to veto it)
+     */
+    public void addVetoers(String callback, Object ... approvers);
+    
+    /** 
+     * Remove one or more vetoers from vetoable object.
+     */
+    public void removeVetoers(Object ... approvers);
+
+}
-- 
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