Node visitor interface, used to walk the DOM and visit each node. Execute via #traverse(Node) or
Node#traverse(NodeVisitor). The traversal is depth-first.
This interface provides two methods, #head and #tail. The head method is called when a node is first
seen, and the tail method when all that node's children have been visited. As an example, head can be used to
emit a start tag for a node, and tail to emit the end tag. The tail method defaults to a no-op, so
this interface can be used as a FunctionalInterface, with head as its single abstract method.
Example:
doc.body().traverse((node, depth) -> {
switch (node) {
case Element el -> print(el.tag() + ": " + el.ownText());
case DataNode data -> print("Data: " + data.getWholeData());
default -> print(node.nodeName() + " at depth " + depth);
}
});
Callback for when a node is first visited.
The node may be modified (for example via Node#attr(String)), removed with
Node#remove(), or replaced with Node#replaceWith(Node). If the node is an
Element, you may cast it and access those methods.
Traversal uses a forward cursor. After head() completes:
head() again. Traversal continues from there: its children are visited,
then the node is passed to #tail(Node, int), then later siblings are visited.tail(), and traversal resumes at the node that originally followed it.Traversal never advances outside the original root subtree. If the traversal root is detached during
head(), traversal stops at the original root boundary.
| name | type | description |
|---|---|---|
| node | org.jsoup.nodes.Node | the node being visited. |
| depth | int | the depth of the node, relative to the root node. E.g., the root node has depth 0, and a child node of that will have depth 1. |
Callback for when a node is last visited, after all of its descendants have been visited.
This method defaults to a no-op.
The node passed to tail() is the node at the current traversal position when the subtree completes.
If head() replaced the original node, this may be the replacement node instead.
Structural changes to the current node are not supported during tail().
| name | type | description |
|---|---|---|
| node | org.jsoup.nodes.Node | the node being visited. |
| depth | int | the depth of the node, relative to the root node. E.g., the root node has depth 0, and a child node of that will have depth 1. |
Run a depth-first traverse of the root and all of its descendants.
| name | type | description |
|---|---|---|
| root | org.jsoup.nodes.Node | the initial node point to traverse. |