Package com.inductiveautomation.ignition.gateway.tags.subscriptions

Interface NodeSubscription

All Superinterfaces:
QualifiedValueListener
All Known Implementing Classes:
AbstractNodePropertyManager.ChangeTrackingNodeSubscription
public interface NodeSubscription extends QualifiedValueListener
Represents the connection between the tag subscription model and the tag execution model. This is provided to executing nodes in order to deliver values to all listeners. To that end, it extends QualifiedValueListener, and the node should call QualifiedValueListener.valueChanged(QualifiedValue) when appropriate.

The node can look at isLeased() as required, though leased state changes will be communicated through calling Node.setLeased(boolean) as well.

Finally, if the node is being destroyed, it must communicate that to the subscription system by calling disconnectNode().

Since:
8.0

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    disconnectNode()
    Should be called by the Node when it is destroyed in order to let the subscription model know that the node is no longer present.
    boolean
    isLeased()
    Indicates that the node has at least one "heavy weight" listener.

    Methods inherited from interface com.inductiveautomation.ignition.common.tags.QualifiedValueListener

    valueChanged

  • Method Details

    • disconnectNode

      void disconnectNode()
      Should be called by the Node when it is destroyed in order to let the subscription model know that the node is no longer present.

    • isLeased

      boolean isLeased()
      Indicates that the node has at least one "heavy weight" listener.
      Returns:
      true if the node should be executing in its "leased" state.