Package edu.wpi.first.networktables

Class NetworkTableListenerPoller

java.lang.Object
edu.wpi.first.networktables.NetworkTableListenerPoller
All Implemented Interfaces:
AutoCloseable
public final class NetworkTableListenerPoller extends Object implements AutoCloseable
Event listener poller. This queues events matching the specified mask. Code using the listener must periodically call readQueue() to read the events.

  • Constructor Details

  • Method Details

    • addListener

      public int addListener(String[] prefixes, EnumSet<NetworkTableEvent.Kind> eventKinds)
      Start listening to topic changes for topics with names that start with any of the given prefixes. This creates a corresponding internal subscriber with the lifetime of the listener.
      Parameters:
      prefixes - Topic name string prefixes
      eventKinds - set of event kinds to listen to
      Returns:
      Listener handle

    • addListener

      public int addListener(Topic topic, EnumSet<NetworkTableEvent.Kind> eventKinds)
      Start listening to changes to a particular topic. This creates a corresponding internal subscriber with the lifetime of the listener.
      Parameters:
      topic - Topic
      eventKinds - set of event kinds to listen to
      Returns:
      Listener handle

    • addListener

      public int addListener(Subscriber subscriber, EnumSet<NetworkTableEvent.Kind> eventKinds)
      Start listening to topic changes on a subscriber. This does NOT keep the subscriber active.
      Parameters:
      subscriber - Subscriber
      eventKinds - set of event kinds to listen to
      Returns:
      Listener handle

    • addListener

      public int addListener(MultiSubscriber subscriber, EnumSet<NetworkTableEvent.Kind> eventKinds)
      Start listening to topic changes on a subscriber. This does NOT keep the subscriber active.
      Parameters:
      subscriber - Subscriber
      eventKinds - set of event kinds to listen to
      Returns:
      Listener handle

    • addListener

      public int addListener(NetworkTableEntry entry, EnumSet<NetworkTableEvent.Kind> eventKinds)
      Start listening to topic changes on an entry.
      Parameters:
      entry - Entry
      eventKinds - set of event kinds to listen to
      Returns:
      Listener handle

    • addConnectionListener

      public int addConnectionListener(boolean immediateNotify)
      Add a connection listener. The callback function is called asynchronously on a separate thread, so it's important to use synchronization or atomics when accessing any shared state from the callback function.
      Parameters:
      immediateNotify - notify listener of all existing connections
      Returns:
      Listener handle

    • addTimeSyncListener

      public int addTimeSyncListener(boolean immediateNotify)
      Add a time synchronization listener. The callback function is called asynchronously on a separate thread, so it's important to use synchronization or atomics when accessing any shared state from the callback function.
      Parameters:
      immediateNotify - notify listener of current time synchronization value
      Returns:
      Listener handle

    • addLogger

      public int addLogger(int minLevel, int maxLevel)
      Add logger callback function. By default, log messages are sent to stderr; this function sends log messages with the specified levels to the provided callback function instead. The callback function will only be called for log messages with level greater than or equal to minLevel and less than or equal to maxLevel; messages outside this range will be silently ignored.
      Parameters:
      minLevel - minimum log level
      maxLevel - maximum log level
      Returns:
      Listener handle

    • removeListener

      public void removeListener(int listener)
      Remove a listener.
      Parameters:
      listener - Listener handle

    • readQueue

      public NetworkTableEvent[] readQueue()
      Read topic notifications.
      Returns:
      Topic notifications since the previous call to readQueue()

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable

    • isValid

      public boolean isValid()
      Determines if the native handle is valid.
      Returns:
      True if the native handle is valid, false otherwise.

    • getHandle

      public int getHandle()
      Gets the native handle.
      Returns:
      Handle