SLING-8271 allow to skip child traversal with a new visit method
diff --git a/src/main/java/org/apache/sling/api/resource/AbstractResourceVisitor.java b/src/main/java/org/apache/sling/api/resource/AbstractResourceVisitor.java
index e152a5f..cfeabb2 100644
--- a/src/main/java/org/apache/sling/api/resource/AbstractResourceVisitor.java
+++ b/src/main/java/org/apache/sling/api/resource/AbstractResourceVisitor.java
@@ -23,24 +23,23 @@
import org.jetbrains.annotations.NotNull;
/**
- * This visitor will traverse the given resource and all its children in a breadth-first approach
- * and call the {@link AbstractResourceVisitor#visit(Resource)} method for each visited resource.
+ * This visitor will traverse the given resource and all its children in a depth-first approach
+ * and call the {@link AbstractResourceVisitor#visitAndContinueWithChildren(Resource)} method for each visited resource.
* It decouples the actual traversal code from application code.
*
* Concrete subclasses must implement the {@link AbstractResourceVisitor#visit(Resource)} method.
*
- * @see <a href="https://en.wikipedia.org/wiki/Breadth-first_search">Breadth-First-Search</a>
+ * @see <a href="https://en.wikipedia.org/wiki/Depth-first_search">Depth-First-Search</a>
* @since 2.2 (Sling API Bundle 2.2.0)
*/
public abstract class AbstractResourceVisitor {
/**
- * Visit the given resource and all its descendants.
+ * Visit the given resource and all its descendants in a depth-first approach.
* @param res The resource
*/
public void accept(final Resource res) {
- if (res != null) {
- this.visit(res);
+ if (res != null && visitAndContinueWithChildren(res)) {
this.traverseChildren(res.listChildren());
}
}
@@ -59,7 +58,20 @@
/**
* Implement this method to do actual work on the resources.
+ * In most of the cases one should rather override {@link #visitAndContinueWithChildren(Resource)} which allows to limit the traversal.
* @param res The resource
*/
protected abstract void visit(final @NotNull Resource res);
+
+ /**
+ * Implement this method to do actual work on the resources and to indicate whether to traverse also the given resource's children.
+ * The default implementation just calls {@link AbstractResourceVisitor#visit(Resource)} and returns {@code true}
+ * @param res The resource
+ * @return {@code true} in case the traversal should also cover the children of {@link #res}.
+ * @since 2.12.0
+ */
+ protected boolean visitAndContinueWithChildren(final @NotNull Resource res) {
+ visit(res);
+ return true;
+ }
}
