Package org.apache.cayenne.event

Class DefaultEventManager

java.lang.Object
org.apache.cayenne.event.DefaultEventManager
All Implemented Interfaces:
EventManager
public class DefaultEventManager extends Object implements EventManager
A default implementation of EventManager.
Since:
3.1

  • Field Details

    • subjects

      protected final Map<EventSubject,org.apache.cayenne.event.DispatchQueue> subjects

    • eventQueue

      protected final List<org.apache.cayenne.event.DefaultEventManager.Dispatch> eventQueue

    • singleThread

      protected final boolean singleThread

    • dispatchThreads

      protected final List<org.apache.cayenne.event.DefaultEventManager.DispatchThread> dispatchThreads

    • stopped

      protected volatile boolean stopped

  • Constructor Details

    • DefaultEventManager

      public DefaultEventManager()
      Creates a multithreaded EventManager using default thread count.

    • DefaultEventManager

      public DefaultEventManager(int dispatchThreadCount)
      Creates an EventManager starting the specified number of threads for multithreaded dispatching. To create a single-threaded EventManager, use thread count of zero or less.

  • Method Details

    • isStopped

      public boolean isStopped()
      Returns true if the EventManager was stopped via shutdown() method.
      Since:
      3.1

    • isSingleThreaded

      public boolean isSingleThreaded()
      Returns true if this EventManager is single-threaded. If so it will throw an exception on any attempt to register an unblocking listener or dispatch a non-blocking event.
      Specified by:
      isSingleThreaded in interface EventManager
      Since:
      1.2

    • shutdown

      @BeforeScopeEnd public void shutdown()
      Stops event threads. After the EventManager is stopped, it can not be restarted and should be discarded.
      Since:
      3.0

    • addListener

      public void addListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)
      Register an EventListener for events sent by any sender.
      Specified by:
      addListener in interface EventManager
      Throws:
      RuntimeException - if methodName is not found
      See Also:

    • addNonBlockingListener

      public void addNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)
      Specified by:
      addNonBlockingListener in interface EventManager

    • addListener

      public void addListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)
      Register an EventListener for events sent by a specific sender.
      Specified by:
      addListener in interface EventManager
      Parameters:
      listener - the object to be notified about events
      methodName - the name of the listener method to be invoked
      eventParameterClass - the class of the single event argument passed to methodName
      subject - the event subject that the listener is interested in
      sender - the object whose events the listener is interested in; null means 'any sender'.
      Throws:
      RuntimeException - if methodName is not found

    • addNonBlockingListener

      public void addNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)
      Specified by:
      addNonBlockingListener in interface EventManager

    • addListener

      protected void addListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender, boolean blocking)

    • removeListener

      public boolean removeListener(Object listener)
      Unregister the specified listener from all event subjects handled by this manager instance.
      Specified by:
      removeListener in interface EventManager
      Parameters:
      listener - the object to be unregistered
      Returns:
      true if listener could be removed for any existing subjects, else returns false.

    • removeAllListeners

      public boolean removeAllListeners(EventSubject subject)
      Removes all listeners for a given subject.
      Specified by:
      removeAllListeners in interface EventManager

    • removeListener

      public boolean removeListener(Object listener, EventSubject subject)
      Unregister the specified listener for the events about the given subject.
      Specified by:
      removeListener in interface EventManager
      Parameters:
      listener - the object to be unregistered
      subject - the subject from which the listener is to be unregistered
      Returns:
      true if listener could be removed for the given subject, else returns false.

    • removeListener

      public boolean removeListener(Object listener, EventSubject subject, Object sender)
      Unregister the specified listener for the events about the given subject and the given sender.
      Specified by:
      removeListener in interface EventManager
      Parameters:
      listener - the object to be unregistered
      subject - the subject from which the listener is to be unregistered
      sender - the object whose events the listener was interested in; null means 'any sender'.
      Returns:
      true if listener could be removed for the given subject, else returns false.

    • postEvent

      public void postEvent(EventObject event, EventSubject subject)
      Sends an event to all registered objects about a particular subject. Event is sent synchronously, so the sender thread is blocked until all the listeners finish processing the event.
      Specified by:
      postEvent in interface EventManager
      Parameters:
      event - the event to be posted to the observers
      subject - the subject about which observers will be notified
      Throws:
      IllegalArgumentException - if event or subject are null

    • postNonBlockingEvent

      public void postNonBlockingEvent(EventObject event, EventSubject subject)
      Sends an event to all registered objects about a particular subject. Event is queued by EventManager, releasing the sender thread, and is later dispatched in a separate thread.
      Specified by:
      postNonBlockingEvent in interface EventManager
      Parameters:
      event - the event to be posted to the observers
      subject - the subject about which observers will be notified
      Throws:
      IllegalArgumentException - if event or subject are null
      Since:
      1.1