[YANGTOOLS-711] XPath: provide an evaluator on top of DataTreeCandidate

Blocks — Thu, 18 Jan 2024 18:05:41 +0000

In order to efficiently propagate state to applications, we want to expose a utility method, which can evaluate a chain of incoming DataTreeCandidates and accurately translate them to a chain of changes to an expression's return values.

The way this should work is:

XPath xpath = ...;
XPathDelta delta = XPathDeltaFactory.initial(xpath);

Collection<DataTreeCandiates> candidates = ...;
for (DataTreeCandidate c : candidates) {
  final Optional<XPathResult> res = delta.apply(c);
  if (res.isPresent()) {
    // Should not result in duplicates printed
    LOG.debug("XPath {} changed result to {}", xpath, res.get());
  }
}
// If no state has been applied, this will return Optional.empty()
Optional<XPathResult> currentResult = delta.current();
LOG.debug("Current XPath {} result is {}", xpath, currentResult);

OpenDaylight JIRA

[YANGTOOLS-711] XPath: provide an evaluator on top of DataTreeCandidate