package us.codecraft.webmagic.selector;
   
   
   import java.util.List;
   import org.apache.commons.collections4.CollectionUtils;
   import org.jsoup.nodes.Element;
   import us.codecraft.xsoup.XPathEvaluator;
   import us.codecraft.xsoup.Xsoup;
   
  /**
   * XPath selector based on Xsoup.<br>
   *
   * @author code4crafter@gmail.com <br>
   * @since 0.3.0
   */
  public class XpathSelector extends BaseElementSelector {
  
      private XPathEvaluator xPathEvaluator;
  
      public XpathSelector(String xpathStr) {
          this.xPathEvaluator = Xsoup.compile(xpathStr);
      }
  
      @Override
      public String select(Element element) {
          return xPathEvaluator.evaluate(element).get();
      }
  
      @Override
      public List<String> selectList(Element element) {
          return xPathEvaluator.evaluate(element).list();
      }
  
      @Override
      public Element selectElement(Element element) {
          List<Element> elements = selectElements(element);
          if (CollectionUtils.isNotEmpty(elements)){
              return elements.get(0);
          }
          return null;
      }
  
      @Override
      public List<Element> selectElements(Element element) {
          return xPathEvaluator.evaluate(element).getElements();
      }
  
      @Override
      public boolean hasAttribute() {
          return xPathEvaluator.hasAttribute();
      }
  }