Package io.zenoh.pubsub

Class Subscriber

  • All Implemented Interfaces:
    io.zenoh.session.SessionDeclaration , java.lang.AutoCloseable 
    
public class Subscriber
 implements AutoCloseable, SessionDeclaration

    A subscriber that allows listening to updates on a key expression and reacting to changes.

    Its main purpose is to keep the subscription active as long as it exists.

    The declaring session holds a strong reference to it: dropping your own reference does NOT stop the subscription — it stays active until close (or undeclare) is called or the session is closed, whichever comes first. Only after that does it become eligible for garbage collection.

    Example using the default BlockingQueueHandler handler:

    var queue = session.declareSubscriber("a/b/c");
try (Session session = Zenoh.open(config)) {
    try (var subscriber = session.declareSubscriber(keyExpr)) {
        var receiver = subscriber.getReceiver();
        assert receiver != null;
        while (true) {
            Optional<Sample> wrapper = receiver.take();
            if (wrapper.isEmpty()) {
                break;
            }
            System.out.println(wrapper.get());
        }
    }
}

    Example using a callback:

    try (Session session = Zenoh.open(config)) {
    session.declareSubscriber(keyExpr, System.out::println);
}

    Example using a handler:

    class MyHandler implements Handler<Sample, ArrayList<Sample>> {...}

//...
try (Session session = Zenoh.open(config)) {
    var handler = new MyHandler();
    var arraylist = session.declareSubscriber(keyExpr, handler);
    // ...
}

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private final KeyExpr keyExpr

    • Constructor Summary

      Constructors 
      Constructor Description

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final KeyExpr getKeyExpr()
      final Boolean isValid()
      Unit undeclare() Undeclare a declaration.
      Unit close()

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait