Package org.apache.jackrabbit.oak.plugins.observation

Interface EventHandler

All Known Implementing Classes:
DefaultEventHandler, FilteredHandler
public interface EventHandler
Handler of content change events. Used to decouple processing of changes from the content diff logic that detects them.

As the content diff recurses down the content tree, it will call the getChildHandler(String, NodeState, NodeState) method to specialize the handler instance for each node under which changes are detected. The other handler methods always apply to the properties and direct children of the node for which that handler instance is specialized. The handler is expected to keep track of contextual information like the path or identifier of the current node based on the sequence of those specialization calls.

The events belonging to this instance should be delivered before events to other instance deeper down the tree are delivered.

All names and paths passed to handler methods use unmapped Oak names.

  • Method Details

    • enter

      void enter(NodeState before, NodeState after)
      Called before the given before and after states are compared. The implementation can use this method to initialize any internal state needed for processing the results of the comparison.
      Parameters:
      before - before state, non-existent if this node was added
      after - after state, non-existent if this node was removed

    • leave

      void leave(NodeState before, NodeState after)
      Called after the given before and after states are compared. The implementation can use this method to post-process information collected during the content diff.
      Parameters:
      before - before state, non-existent if this node was added
      after - after state, non-existent if this node was removed

    • getChildHandler

      @Nullable @Nullable EventHandler getChildHandler(String name, NodeState before, NodeState after)
      Returns a handler of events within the given child node, or null if changes within that child are not to be processed.
      Parameters:
      name - name of the child node
      before - before state of the child node, possibly non-existent
      after - after state of the child node, possibly non-existent
      Returns:
      handler of events within the child node, or null

    • propertyAdded

      void propertyAdded(PropertyState after)
      Notification for an added property
      Parameters:
      after - added property

    • propertyChanged

      void propertyChanged(PropertyState before, PropertyState after)
      Notification for a changed property
      Parameters:
      before - property before the change
      after - property after the change

    • propertyDeleted

      void propertyDeleted(PropertyState before)
      Notification for a deleted property
      Parameters:
      before - deleted property

    • nodeAdded

      void nodeAdded(String name, NodeState after)
      Notification for an added node
      Parameters:
      name - name of the node
      after - added node

    • nodeDeleted

      void nodeDeleted(String name, NodeState before)
      Notification for a deleted node
      Parameters:
      name - name of the deleted node
      before - deleted node

    • nodeMoved

      void nodeMoved(String sourcePath, String name, NodeState moved)
      Notification for a moved node
      Parameters:
      sourcePath - source of the moved node
      name - name of the moved node
      moved - moved node

    • nodeReordered

      void nodeReordered(String destName, String name, NodeState reordered)
      Notification for a reordered node
      Parameters:
      destName - name of the orderBefore() destination node
      name - name of the moved node
      reordered - moved node