XMLParser.java :  » UnTagged » android-daisy-epub-reader » com » ader » Android Open Source

package com.ader;

import java.io.IOException;
import java.io.InputStream;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

/*
 * Non JavaDoc
 * TODO(jharty):
 * 1. Somewhere we need to either add preconditions (to assert the basic
 *  structure is acceptable and as expected) or handle problematic content more
 *  robustly. e.g. at the moment we gayly dereference things like:
 *  document.getElementsByTagName("body").item(0).getChildNodes() without
 *  checking for nulls being returned by the intervening calls.
 */
public class XMLParser {
  private static final String TAG = "XMLParser";
  private Document document;
  private NavCentre navCentre;

  /**
   * Parses a valid Daisy 2.02 ncc.html document.
   * 
   * @param input valid Daisy 2.02 content.
   */
  public XMLParser(InputStream input) {
    navCentre = new NavCentre();  
    DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();

    try {
      builderFactory
          .setFeature(
              "http://apache.org/xml/features/nonvalidating/load-external-dtd",
              false);
      document = builderFactory.newDocumentBuilder().parse(input);
    } catch (ParserConfigurationException e) {
      e.printStackTrace();
    } catch (SAXException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * Processes the NCC contents to generate a NavCentre object.
   * 
   * Currently we only process the h1 through h1 elements. And we assume
   * the content is valid, otherwise various exceptions, including a null
   * pointer may be thrown.
   * 
   * @return the NavCentre object.
   */
  public NavCentre processNCC() {
    // get a list of all the tags inside the body element
    NodeList body = document.getElementsByTagName("body").item(0).getChildNodes();
        
    for (int i = 0; i < body.getLength(); i++) {
      Node currentNode = body.item(i);
      
      // is it a heading tag
      if (currentNode.getNodeName().matches("h[123456]")) 
        handleNCChTag(currentNode);
      
      // is it a span tag
       if (currentNode.getNodeName().equalsIgnoreCase("span"))
        handleNCCspanTag(currentNode);
    }
    
    return navCentre;
  }
  
  private void handleNCChTag(Node heading) {
    int level = Integer.decode(heading.getNodeName().substring(1));
    NavPoint navPoint = new NavPoint(heading.getFirstChild(), level);

    navCentre.addNavPoint(navPoint);
  }

  // TODO(gary): How do you suggest we handle page-numbers? 
  private void handleNCCspanTag(Node span) {
    Node value = span.getFirstChild();
    Util.logInfo(TAG, "span found, containing: " + value.toString());
//    NCCEntry entry = new NCCEntry(span.getFirstChild(), NCCEntryType.PAGENUMBER, 0);  
    //System.out.println(entry.getText());  
  }
}