= ValidityEvent
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Supported only by xref:refguide:applib:index/services/wrapper/WrapperFactory.adoc[WrapperFactory] , represents a check to determine whether a proposed change is valid.

Multiple subclasses, including:

* modifying a property
* adding to/removing from a collection
* checking a single argument for an action invocation
* checking all arguments for an action invocation
* checking all properties for an object before saving

If _#getReason()_ is `null` , then is usable; otherwise is disabled.

== API

[source,java]
.ValidityEvent.java
----
class ValidityEvent {
  ValidityEvent(Object source, Identifier identifier)
  Object getSource()
  String getReasonMessage()
}
----

