A DOM Parse Tree Lister : DOM Parser « XML « Java Tutorial

1. Java Tutorial
2. XML
3. DOM Parser

1. Using the DOM Parser to Build a Document Tree
2. A Class That Walks through a DOM Parse Tree

import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
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.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

public class DOMDump {
  static public void main(String[] arg) {
    boolean validate = true;

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setValidating(validate);
    dbf.setNamespaceAware(true);
    dbf.setIgnoringElementContentWhitespace(true);

    // Parse the input to produce a parse tree with its root
    // in the form of a Document object
    Document doc = null;
    try {
      DocumentBuilder builder = dbf.newDocumentBuilder();
      builder.setErrorHandler(new MyErrorHandler());
      InputSource is = new InputSource("personWithDTD.xml");
      doc = builder.parse(is);
    } catch (SAXException e) {
      System.exit(1);
    } catch (ParserConfigurationException e) {
      System.err.println(e);
      System.exit(1);
    } catch (IOException e) {
      System.err.println(e);
      System.exit(1);
    }
    dump(doc);
  }

  private static void dump(Document doc) {
    dumpLoop((Node) doc, "");
  }

  private static void dumpLoop(Node node, String indent) {
    switch (node.getNodeType()) {
    case Node.CDATA_SECTION_NODE:
      System.out.println(indent + "CDATA_SECTION_NODE");
      break;
    case Node.COMMENT_NODE:
      System.out.println(indent + "COMMENT_NODE");
      break;
    case Node.DOCUMENT_FRAGMENT_NODE:
      System.out.println(indent + "DOCUMENT_FRAGMENT_NODE");
      break;
    case Node.DOCUMENT_NODE:
      System.out.println(indent + "DOCUMENT_NODE");
      break;
    case Node.DOCUMENT_TYPE_NODE:
      System.out.println(indent + "DOCUMENT_TYPE_NODE");
      break;
    case Node.ELEMENT_NODE:
      System.out.println(indent + "ELEMENT_NODE");
      break;
    case Node.ENTITY_NODE:
      System.out.println(indent + "ENTITY_NODE");
      break;
    case Node.ENTITY_REFERENCE_NODE:
      System.out.println(indent + "ENTITY_REFERENCE_NODE");
      break;
    case Node.NOTATION_NODE:
      System.out.println(indent + "NOTATION_NODE");
      break;
    case Node.PROCESSING_INSTRUCTION_NODE:
      System.out.println(indent + "PROCESSING_INSTRUCTION_NODE");
      break;
    case Node.TEXT_NODE:
      System.out.print(indent + "TEXT_NODE");
      System.out.println(" : "+node.getTextContent());
      break;
    default:
      System.out.println(indent + "Unknown node");
      break;
    }

    NodeList list = node.getChildNodes();
    for (int i = 0; i < list.getLength(); i++){
      dumpLoop(list.item(i), indent + "   ");
    }
  }
}


class MyErrorHandler implements ErrorHandler {
  public void warning(SAXParseException e) throws SAXException {
    show("Warning", e);
    throw (e);
  }

  public void error(SAXParseException e) throws SAXException {
    show("Error", e);
    throw (e);
  }

  public void fatalError(SAXParseException e) throws SAXException {
    show("Fatal Error", e);
    throw (e);
  }

  private void show(String type, SAXParseException e) {
    System.out.println(type + ": " + e.getMessage());
    System.out.println("Line " + e.getLineNumber() + " Column " + e.getColumnNumber());
    System.out.println("System ID: " + e.getSystemId());
  }
}

//File: personWithDTD.xml
<?xml version="1.0" standalone="yes"?>

<!-- This document is both well formed and valid -->

<!DOCTYPE folks [
<!ELEMENT folks (person)*>
<!ELEMENT person (name, phone, email)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT phone (#PCDATA)>
<!ELEMENT email (#PCDATA)>
]>

<folks>
    <person>
        <name>B D</name>
        <phone>999 555-8888</phone>
        <email>b@xyz.net</email>
    </person>
</folks>

DOCUMENT_NODE
   COMMENT_NODE
   DOCUMENT_TYPE_NODE
   ELEMENT_NODE
      ELEMENT_NODE
         ELEMENT_NODE
            TEXT_NODE : B D
         ELEMENT_NODE
            TEXT_NODE : 999 555-8888
         ELEMENT_NODE
            TEXT_NODE : b@xyz.net