Class PropertyChangeEvent

  • All Implemented Interfaces:
    Serializable

    public class PropertyChangeEvent
    extends EventObject
    An event object describing a change to a named property.

    This concrete class was designed to be instantiated, but may also be subclassed if required.

    The JFace frameworks contain classes that report property change events for internal state changes that may be of interest to external parties. A special listener interface (IPropertyChangeListener) is defined for this purpose, and a typical class allow listeners to be registered via an addPropertyChangeListener method.

    See Also:
    IPropertyChangeListener, Serialized Form
    • Constructor Detail

      • PropertyChangeEvent

        public PropertyChangeEvent​(Object source,
                                   String property,
                                   Object oldValue,
                                   Object newValue)
        Creates a new property change event.
        Parameters:
        source - the object whose property has changed
        property - the property that has changed (must not be null)
        oldValue - the old value of the property, or null if none
        newValue - the new value of the property, or null if none
    • Method Detail

      • getNewValue

        public Object getNewValue()
        Returns the new value of the property.
        Returns:
        the new value, or null if not known or not relevant (for instance if the property was removed).
      • getOldValue

        public Object getOldValue()
        Returns the old value of the property.
        Returns:
        the old value, or null if not known or not relevant (for instance if the property was just added and there was no old value).
      • getProperty

        public String getProperty()
        Returns the name of the property that changed.

        Warning: there is no guarantee that the property name returned is a constant string. Callers must compare property names using equals, not ==.

        Returns:
        the name of the property that changed