Handler of node state differences. The {@link NodeStore#compare(NodeState,NodeState,NodeStateDiff)} reportsdetected node state differences by calling methods of a handler instance that implements this interface. The compare method will go through all properties and child nodes of the two states, calling the relevant added, changed or deleted methods where appropriate. Differences in the ordering of properties or child nodes do not affect the comparison, and the order in which such differences are reported is unspecified.
Note that the {@link NodeStore#compare(NodeState,NodeState,NodeStateDiff)}method only compares the given states without recursing to the subtrees below. An implementation of this interface should recursively call that method for the relevant child node entries to find out all the changes across the entire subtree below the given node.