filter out invisible elements

src/com/dom_distiller/client/ContentExtractor.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package com.dom_distiller.client;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.logging.Logger;
 
 import com.google.gwt.dom.client.AnchorElement;
 import com.google.gwt.dom.client.Document;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.ImageElement;
 import com.google.gwt.dom.client.Node;
 import com.google.gwt.dom.client.NodeList;
 
 import de.l3s.boilerpipe.BoilerpipeProcessingException;
 import de.l3s.boilerpipe.document.TextBlock;
 import de.l3s.boilerpipe.document.TextDocument;
 import de.l3s.boilerpipe.extractors.CommonExtractors;
 import de.l3s.boilerpipe.labels.DefaultLabels;
 import de.l3s.boilerpipe.sax.BoilerpipeHTMLContentHandler;
 
 import org.timepedia.exporter.client.Export;
 import org.timepedia.exporter.client.Exportable;
 
 import org.xml.sax.AttributesImpl;
+import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
 
 @Export()
 public class ContentExtractor implements Exportable {
     static Logger logger = Logger.getLogger("DomDistiller");
 
     public static String extractContent() {
         BoilerpipeHTMLContentHandler htmlParser = new BoilerpipeHTMLContentHandler();
         List<Node> textNodes = null;
 
         try {
             htmlParser.startDocument();
             Element documentElement = Document.get().getDocumentElement();
-            textNodes = DomToSaxParser.parse(documentElement, htmlParser);
+            textNodes = parse(documentElement, htmlParser);
             htmlParser.endDocument();
         } catch (SAXException e) {
             logger.warning("Parsing failed.");
             return "";
         }
 
         TextDocument document = htmlParser.toTextDocument();
         try {
             CommonExtractors.ARTICLE_EXTRACTOR.process(document);
         } catch (BoilerpipeProcessingException e) {
@@ skipping 31 matching lines @@
         // The base URL in the distilled page viewer is different from that in
         // the live page.  This breaks all relative links (in anchors and
         // images), so make them absolute in the distilled content.
         makeAllLinksAbsolute(clonedSubtree);
 
         // TODO(cjhopman): this discards the top element and just returns its children. This might
         // break in some cases.
         return Element.as(clonedSubtree).getInnerHTML();
     }
 
+    private static List<Node> parse(Element e, ContentHandler handler) {
+        DomToSaxVisitor domToSaxVisitor = new DomToSaxVisitor(handler);
+        FilteringDomVisitor filteringDomVisitor = new FilteringDomVisitor(domToSaxVisitor);
+        new DomWalker(filteringDomVisitor).walk(e);
+        return domToSaxVisitor.getTextNodes();
+    }
+
     private static void makeAllLinksAbsolute(Node rootNode) {
         Element root = Element.as(rootNode);
 
         // AnchorElement.getHref() and ImageElement.getSrc() both return the
         // absolute URI, so simply set them as the respective attributes.
 
         NodeList<Element> allLinks = root.getElementsByTagName("A");
         for (int i = 0; i < allLinks.getLength(); i++) {
             AnchorElement link = AnchorElement.as(allLinks.getItem(i));
             link.setHref(link.getHref());
         }
 
         NodeList<Element> allImages = root.getElementsByTagName("IMG");
         for (int i = 0; i < allImages.getLength(); i++) {
             ImageElement image = ImageElement.as(allImages.getItem(i));
             image.setSrc(image.getSrc());
         }
     }
 }