Package eu.maveniverse.domtrip

Interface DomTripVisitor

public interface DomTripVisitor
Visitor interface for structured depth-first tree traversal with enter/exit lifecycle callbacks.

This complements the existing stream-based navigation (Element.descendants(), ElementQuery) with a pattern better suited for transformations needing context tracking (depth, ancestors, accumulated state).

Traversal Order:

The visitor performs a depth-first traversal: for each element, enterElement(Element) is called first, then all children are visited recursively, and finally exitElement(Element) is called.

Flow Control:

Visit methods return an DomTripVisitor.Action to control traversal:

Usage Example:


 element.accept(new DomTripVisitor() {
     @Override
     public Action enterElement(Element e) {
         if ("metadata".equals(e.localName())) {
             return Action.SKIP; // don't descend into metadata
         }
         System.out.println("Entering: " + e.name());
         return Action.CONTINUE;
     }

     @Override
     public void exitElement(Element e) {
         System.out.println("Exiting: " + e.name());
     }

     @Override
     public Action visitComment(Comment c) {
         System.out.println("Comment: " + c.content());
         return Action.CONTINUE;
     }
 });

Stateful Visitor Example:


 class NamespaceCollector implements DomTripVisitor {
     private final Map<String, String> namespaces = new LinkedHashMap<>();
     private final Deque<String> path = new ArrayDeque<>();

     @Override
     public Action enterElement(Element e) {
         path.push(e.localName());
         String ns = e.namespaceURI();
         if (ns != null && !namespaces.containsKey(ns)) {
             namespaces.put(ns, String.join("/", path));
         }
         return Action.CONTINUE;
     }

     @Override
     public void exitElement(Element e) {
         path.pop();
     }

     public Map<String, String> result() { return namespaces; }
 }
Since:
1.3.0
See Also: