Changes between Version 43 and Version 44 of PRO_LIB_CORE_TUTORIAL

Timestamp:

07/14/09 15:25:56 (16 years ago)

Author:

peko

Comment:

--

PRO_LIB_CORE_TUTORIAL

@@ -745 +745 @@
 }}}
 
-
+ ==== Accessing a parent property that has not been initialized (usually set to null) ====
+
+ * Suppose one has the following code:
+{{{
+
+       class Child extends BaseProObject {
+
+                public Prop<Parent> parent() {
+                        return getBean().makeParentProp(Parent.class);
+                }
+                
+        }
+        
+        class Parent extends BaseProObject {
+                
+                @Own
+                public RwProp<Child> child() {
+                        return getBean().makeValueProp("child", Child.class);
+                }       
+                
+        }
+
+}}}
+  
+  * If one tries to do the thing below a NotAvailableException will be thrown.
+{{{
+                Parent parent = new Parent();
+                Child child = new Child();
+                child.parent().get(); //null at this point.
+                parent.child().get(); //throws NotAvailableException
+}}}
+  In order to use the above relation see...
+{{{
+
+                Parent parent = new Parent();
+                Child child = new Child();
+                parent.child().set(child);
+                child.parent().get(); // child.parent().get() == parent
+}}}
 
 == Debugging ProLib ==