Property change event concept

UML model uses standard java.beans.PropertyChangeEvent events for notifying listeners about changes.

The main properties of the PropertyChangeEvent are as follows:

  • Property name. The changed property name.

  • New value. The new (current) changed property value.

  • Old value. The old property value, which was before the property change.

Properties names are described in UML model properties names page

Example of the element’s name change event

propertyChangeEvent.getPropertyName().equals(PropertyNames.NAME);
propertyChangeEvent.getNewValue() // will be new name of element;
propertyChangeEvent.getOldValue() // will be name of element before change.

Example of the new element creation event

propertyChangeEvent.getPropertyName().equals(UML2MetamodelConstants.INSTANCE_CREATED);
propertyChangeEvent.getNewValue() // will be new created element;
propertyChangeEvent.getOldValue() // will be null.