org.jsoup.select.NodeTraversor Maven / Gradle / Ivy
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SDK for dev_appserver (local development) with some of the dependencies shaded (repackaged)
package org.jsoup.select;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Node;
import org.jsoup.select.NodeFilter.FilterResult;
/**
A depth-first node traversor. Use to walk through all nodes under and including the specified root node, in document
order. The {@link NodeVisitor#head(Node, int)} and {@link NodeVisitor#tail(Node, int)} methods will be called for
each node.
During traversal, structural changes to nodes are supported (e.g. {{@link Node#replaceWith(Node)},
{@link Node#remove()}}
*/
public class NodeTraversor {
/**
Run a depth-first traverse of the root and all of its descendants.
@param visitor Node visitor.
@param root the initial node point to traverse.
@see NodeVisitor
*/
public static void traverse(NodeVisitor visitor, Node root) {
Validate.notNull(visitor);
Validate.notNull(root);
Node node = root;
int depth = 0;
while (node != null) {
Node parent = node.parentNode(); // remember parent to find nodes that get replaced in .head
int origSize = parent != null ? parent.childNodeSize() : 0;
Node next = node.nextSibling();
visitor.head(node, depth); // visit current node
if (parent != null && !node.hasParent()) { // removed or replaced
if (origSize == parent.childNodeSize()) { // replaced
node = parent.childNode(node.siblingIndex()); // replace ditches parent but keeps sibling index
} else { // removed
node = next;
if (node == null) { // last one, go up
node = parent;
depth--;
}
continue; // don't tail removed
}
}
if (node.childNodeSize() > 0) { // descend
node = node.childNode(0);
depth++;
} else {
while (true) {
assert node != null; // as depth > 0, will have parent
if (!(node.nextSibling() == null && depth > 0)) break;
visitor.tail(node, depth); // when no more siblings, ascend
node = node.parentNode();
depth--;
}
visitor.tail(node, depth);
if (node == root)
break;
node = node.nextSibling();
}
}
}
/**
Run a depth-first traversal of each Element.
@param visitor Node visitor.
@param elements Elements to traverse.
*/
public static void traverse(NodeVisitor visitor, Elements elements) {
Validate.notNull(visitor);
Validate.notNull(elements);
for (Element el : elements)
traverse(visitor, el);
}
/**
Run a depth-first filtered traversal of the root and all of its descendants.
@param filter NodeFilter visitor.
@param root the root node point to traverse.
@return The filter result of the root node, or {@link FilterResult#STOP}.
@see NodeFilter
*/
public static FilterResult filter(NodeFilter filter, Node root) {
Node node = root;
int depth = 0;
while (node != null) {
FilterResult result = filter.head(node, depth);
if (result == FilterResult.STOP)
return result;
// Descend into child nodes:
if (result == FilterResult.CONTINUE && node.childNodeSize() > 0) {
node = node.childNode(0);
++depth;
continue;
}
// No siblings, move upwards:
while (true) {
assert node != null; // depth > 0, so has parent
if (!(node.nextSibling() == null && depth > 0)) break;
// 'tail' current node:
if (result == FilterResult.CONTINUE || result == FilterResult.SKIP_CHILDREN) {
result = filter.tail(node, depth);
if (result == FilterResult.STOP)
return result;
}
Node prev = node; // In case we need to remove it below.
node = node.parentNode();
depth--;
if (result == FilterResult.REMOVE)
prev.remove(); // Remove AFTER finding parent.
result = FilterResult.CONTINUE; // Parent was not pruned.
}
// 'tail' current node, then proceed with siblings:
if (result == FilterResult.CONTINUE || result == FilterResult.SKIP_CHILDREN) {
result = filter.tail(node, depth);
if (result == FilterResult.STOP)
return result;
}
if (node == root)
return result;
Node prev = node; // In case we need to remove it below.
node = node.nextSibling();
if (result == FilterResult.REMOVE)
prev.remove(); // Remove AFTER finding sibling.
}
// root == null?
return FilterResult.CONTINUE;
}
/**
Run a depth-first filtered traversal of each Element.
@param filter NodeFilter visitor.
@see NodeFilter
*/
public static void filter(NodeFilter filter, Elements elements) {
Validate.notNull(filter);
Validate.notNull(elements);
for (Element el : elements)
if (filter(filter, el) == FilterResult.STOP)
break;
}
}