package us.codecraft.webmagic.selector;
   
   import java.util.ArrayList;
   import java.util.List;
   
   /**
    * All selectors will be arranged as a pipeline. <br>
    * The next selector uses the result of the previous as source.
    * @author code4crafter@gmail.com <br>
   * @since 0.2.0
   */
  public class AndSelector implements Selector {
  
      private List<Selector> selectors = new ArrayList<Selector>();
  
      public AndSelector(Selector... selectors) {
          for (Selector selector : selectors) {
              this.selectors.add(selector);
          }
      }
  
      public AndSelector(List<Selector> selectors) {
          this.selectors = selectors;
      }
  
      @Override
      public String select(String text) {
          for (Selector selector : selectors) {
              if (text == null) {
                  return null;
              }
              text = selector.select(text);
          }
          return text;
      }
  
      @Override
      public List<String> selectList(String text) {
          List<String> results = new ArrayList<String>();
          boolean first = true;
          for (Selector selector : selectors) {
              if (first) {
                  results = selector.selectList(text);
                  first = false;
              } else {
                  List<String> resultsTemp = new ArrayList<String>();
                  for (String result : results) {
                      resultsTemp.addAll(selector.selectList(result));
                  }
                  results = resultsTemp;
                  if (results == null || results.size() == 0) {
                      return results;
                  }
              }
          }
          return results;
      }
  }