Comparing Two Xml Files

package com.blogspot.abbablows.tests;

import java.io.File;
import java.io.FileInputStream;
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.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import junit.framework.TestCase;

/**
* JUnit test shows one method of comparing two xml files
*/

public class Example extends TestCase
{
  protected void compareFiles(File actual,
                              File expected,
                              String elementName)
  throws ParserConfigurationException, SAXException, 
    IOException
  {
    FileInputStream fileOne = null;
    FileInputStream fileTwo = null;

    try
    {
      DocumentBuilderFactory factory = 
        DocumentBuilderFactory.newInstance();

      DocumentBuilder builder = factory.newDocumentBuilder();

      fileOne = new FileInputStream(actual);
      Document firstDocument = builder.parse(fileOne);
      firstDocument.getDocumentElement().normalize();
      NodeList firstRoot =
        firstDocument.getElementsByTagName(elementName);
  
      fileTwo = new FileInputStream(expected);
      Document secondDocument = builder.parse(fileTwo);
      secondDocument.getDocumentElement().normalize();
      NodeList secondRoot =
        secondDocument.getElementsByTagName(elementName);
      walkNodes(firstRoot, secondRoot);
    }
    finally
    {
      if (fileOne != null)
      {
        fileOne.close();
      }

      if (fileTwo != null)
      {
        fileTwo.close();
      }
    }   
  }

  private void walkNodes(NodeList firstRoot, 
                         NodeList secondRoot)
  {
    assertEquals(firstRoot.getLength(), secondRoot.getLength());

    for (int i = 0; i < firstRoot.getLength(); i++)
    {
      Node itemOne = firstRoot.item(i);
      String nameOne = itemOne.getNodeName();
      String valueOne = itemOne.getNodeValue();

      Node itemTwo = secondRoot.item(i);
      String nameTwo = itemTwo.getNodeName();
      String valueTwo = itemTwo.getNodeValue();

      if (itemOne.hasChildNodes())
      {
        walkNodes(itemOne.getChildNodes(),
        itemTwo.getChildNodes());
      }
 
      if (itemOne.hasAttributes())
      {
        doAttributes(itemOne, itemTwo);
      }

      assertEquals(nameOne, nameTwo);

      if (valueOne != null && valueTwo != null)
      {
        assertEquals(valueOne.trim(), valueTwo.trim());
      }
    }
  }

  private void doAttributes(Node firstRoot, Node secondRoot)
  {
    NamedNodeMap mapOne = firstRoot.getAttributes();
    NamedNodeMap mapTwo = secondRoot.getAttributes();

    assertEquals(mapOne.getLength(), mapTwo.getLength());

    for (int i = 0; i < mapOne.getLength(); i++)
    {
      Node itemOne = mapOne.item(i);
      String nameOne = itemOne.getNodeName();
      String valueOne = itemOne.getNodeValue();

      Node itemTwo = mapTwo.item(i);
      String nameTwo = itemTwo.getNodeName();
      String valueTwo = itemTwo.getNodeValue();

      assertEquals(nameOne, nameTwo);

      if (valueOne != null && valueTwo != null)
      {
        assertEquals(valueOne.trim(), valueTwo.trim());
      }
    }
  }
}