.. java:import:: java.util HashSet

.. java:import:: java.util Set

.. java:import:: java.util.logging Logger

FilterObservable
================

.. java:package:: rsb.filter
   :noindex:

.. java:type:: public class FilterObservable

   Utility class maintaining a list of \ :java:ref:`FilterObserver`\  instances and the required methods to notify these instances about filter changes. This class is not thread-safe.

   :author: swrede, jwienke

Methods
-------
addObserver
^^^^^^^^^^^

.. java:method:: public boolean addObserver(FilterObserver observer)
   :outertype: FilterObservable

   If not already registered, adds this observer to the list of registered observers.

   :param observer: observer to add
   :return: \ ``true``\  if the observer was actually newly registered.

clearObservers
^^^^^^^^^^^^^^

.. java:method:: public void clearObservers()
   :outertype: FilterObservable

   Removes all registered observers.

notifyObservers
^^^^^^^^^^^^^^^

.. java:method:: public void notifyObservers(Filter filter, FilterAction action)
   :outertype: FilterObservable

   Notifies all registered observers about a change to a \ :java:ref:`Filter`\ .

   :param filter: the filter that is affected, not \ ``null``\
   :param action: the action performed to the filter, not \ ``null``\

removeObserver
^^^^^^^^^^^^^^

.. java:method:: public boolean removeObserver(FilterObserver observer)
   :outertype: FilterObservable

   Removes a potentially registered observer.

   :param observer: the observer to remove
   :return: \ ``true``\  if the observer was previously registered and is now unregistered