ai.platon.pulsar.dom.select.PowerCollector.kt Maven / Gradle / Ivy
package ai.platon.pulsar.dom.select
import org.jsoup.nodes.Element
import org.jsoup.nodes.Node
import org.jsoup.select.*
object PowerCollector {
/**
* Build a list of elements, by visiting root and every descendant of root, and testing it against the evaluator.
* @param eval Evaluator to test elements against
* @param root root of tree to descend
* @return list of matches; empty if none
*/
fun collect(eval: Evaluator, root: Element): Elements {
val elements = Elements()
NodeTraversor.traverse(Accumulator(root, elements, eval), root)
return elements
}
fun findFirst(eval: Evaluator, root: Element): Element? {
val finder = FirstFinder(root, eval)
NodeTraversor.filter(finder, root)
return finder.match
}
private class Accumulator(val root: Element, val elements: Elements, val eval: Evaluator): NodeVisitor {
override fun head(node: Node, depth: Int) {
if (node is Element) {
if (eval.matches(root, node)) elements.add(node)
}
}
override fun tail(node: Node, depth: Int) { // void
}
}
private class FirstFinder(val root: Element, val eval: Evaluator): NodeFilter {
var match: Element? = null
override fun head(node: Node, depth: Int): NodeFilter.FilterResult {
if (node is Element) {
if (eval.matches(root, node)) {
match = node
return NodeFilter.FilterResult.STOP
}
}
return NodeFilter.FilterResult.CONTINUE
}
override fun tail(node: Node, depth: Int): NodeFilter.FilterResult {
return NodeFilter.FilterResult.CONTINUE
}
}
}