XML Validation against XSD(s) - Code

There any many tools available to validate an XML document against an XSD. These include operating system scripts and tools such as xmllint, XMLTools plugin in NotePad++ and many online validators. Java makes it easy to write such a tool and this post demonstrates a utility created in Java for XML validation.

XML Validation against XSD(s) Utility

This is a small utility created using Java Swing and XML Validations which will help validating an XML File against N number of XSD Files. There are a total of 3 classes written and explained as below.

1. MyValidationHandler.java - A custom validation class written to print all the errors in the XML document in a specific format.
2. XMLUtils.java - Utility class to validate the type of files selected before starting validation.
3. ValidateXML.java - Main class to display the UI and take XML and XSD(s) as input.

MyValidationHandler.java 

import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import com.del.main.ValidateXML;

public class MyValidationHandler extends DefaultHandler {

@Override
public void warning(SAXParseException e) throws SAXException {
ValidateXML.exceptions.add(printInfo(e));
}

@Override
public void error(SAXParseException e) throws SAXException {
ValidateXML.exceptions.add(printInfo(e));
}

@Override
public void fatalError(SAXParseException e) throws SAXException {
ValidateXML.exceptions.add(printInfo(e));
}

private String printInfo(SAXParseException e) {

StringBuffer result = new StringBuffer();
result.append("ERROR: " + e.getMessage() + "\n");
result.append("   Line number: " + e.getLineNumber() + "\n");
result.append("   Column number: " + e.getColumnNumber());

return result.toString();
}

}

XMLUtils.java

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.swing.JFileChooser;

public class XMLUtils {

private static Pattern xmlfileExtnPtrn = Pattern
.compile("([^\\s]+(\\.(?i)(xml))$)");
private static Pattern xsdfileExtnPtrn = Pattern
.compile("([^\\s]+(\\.(?i)(xsd))$)");

public static boolean validateFileExtn(String fileName, String xmlOrxsd) {
Matcher mtch = null;
if ("xml".equals(xmlOrxsd)) {
mtch = xmlfileExtnPtrn.matcher(fileName);
} else if ("xsd".equals(xmlOrxsd)) {
mtch = xsdfileExtnPtrn.matcher(fileName);
} else {
return false;
}
if (mtch.matches()) {
return true;
}
return false;
}

public static String chooseFile(String filePath) {

JFileChooser fileChooser = new JFileChooser(filePath);
int fileResult = fileChooser.showOpenDialog(null);

if (fileResult == JFileChooser.APPROVE_OPTION) {
return fileChooser.getSelectedFile().getAbsolutePath();
}
return null;
}

}

ValidateXML.java

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.border.TitledBorder;
import javax.xml.XMLConstants;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;

import org.xml.sax.SAXException;

import com.del.utils.XMLUtils;
import com.del.validationHandler.MyValidationHandler;

public class ValidateXML {

public static String filePath = null;
static JLabel errorMessage = new JLabel();
static JTextField xmlFileName = new JTextField();
static List<JTextField> xsdFileNames = new ArrayList<JTextField>();
static List<JButton> xsdBrowseButtons = new ArrayList<JButton>();
static JPanel myPanel = new JPanel();
static JFrame frame = new JFrame("Validate XML Utility");
static List<String> xsdStringFileNames = new ArrayList<String>();
static boolean validate = false;
public static List<String> exceptions = new ArrayList<String>();

public static void main(String[] args) {

filePath = System.getProperty("user.home") + "\\Desktop";
viewUI();
}

public static void validateXml(String xmlFileName,
List<String> xsdFileName) {

exceptions = new ArrayList<String>();

SchemaFactory schemaFactory = SchemaFactory
.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
StreamSource[] xsdSources = generateStreamSourcesFromXsdPath(xsdFileName);

try {
Schema schema = schemaFactory.newSchema(xsdSources);

Validator validator = schema.newValidator();
validator.setErrorHandler(new MyValidationHandler());
validator.validate(new StreamSource(new File(xmlFileName)));

} catch (IOException exception) {
JOptionPane.showMessageDialog(null, "ERROR: Unable to validate " + xmlFileName
+ " against XSDs " + xsdFileName + " - " + exception, "Message",
JOptionPane.ERROR_MESSAGE);
} catch (SAXException exception) {
JOptionPane.showMessageDialog(null, "ERROR: Unable to validate " + xmlFileName
+ " against XSDs " + xsdFileName + " - " + exception, "Message",
JOptionPane.ERROR_MESSAGE);
}
}

private static StreamSource[] generateStreamSourcesFromXsdPath(
List<String> xsdFileName) {
List<StreamSource> streamSources = new ArrayList<StreamSource>();
for (String xsdPath : xsdFileName) {
streamSources.add(new StreamSource(xsdPath));
}
return streamSources.toArray(new StreamSource[xsdFileName.size()]);
}

private static void viewUI() {

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

myPanel = new JPanel(new BorderLayout(5, 5));
myPanel.setBorder(new TitledBorder(""));

JPanel plafComponents = new JPanel(new GridLayout(0,2,2,2));
plafComponents.setBorder(new TitledBorder("Change the Look and Feel"));

final UIManager.LookAndFeelInfo[] plafInfos = UIManager
.getInstalledLookAndFeels();
String[] plafNames = new String[plafInfos.length];
for (int ii = 0; ii < plafInfos.length; ii++) {
plafNames[ii] = plafInfos[ii].getName();
}
final JComboBox plafChooser = new JComboBox(plafNames);
plafComponents.add(plafChooser);

final JCheckBox pack = new JCheckBox("Auto-resize on theme changes",
true);
plafComponents.add(pack);

plafChooser.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
int index = plafChooser.getSelectedIndex();
try {
UIManager.setLookAndFeel(plafInfos[index].getClassName());
SwingUtilities.updateComponentTreeUI(frame);
if (pack.isSelected()) {
frame.pack();
frame.setMinimumSize(frame.getSize());
}
} catch (Exception e) {
e.printStackTrace();
}
}
});

myPanel.add(plafComponents, BorderLayout.NORTH);

JPanel dynamicLabels = new JPanel(new BorderLayout(4, 4));
dynamicLabels.setBorder(new TitledBorder("Select Files"));
myPanel.add(dynamicLabels, BorderLayout.CENTER);

final JPanel labels = new JPanel(new GridLayout(0, 1, 2, 2));
labels.setBorder(new TitledBorder(""));

labels.add(new JLabel("XML File :"));
labels.add(xmlFileName);
JButton xmlBrowse = new JButton("Browse");
labels.add(xmlBrowse);

xmlBrowse.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
xmlFileName.setText(XMLUtils.chooseFile(filePath));
}
});

JButton addNew = new JButton("Add XSD File");

addNew.addActionListener(new ActionListener() {
private int labelCount = 0;

public void actionPerformed(ActionEvent ae) {
labels.add(new JLabel("XSD File " + ++labelCount + " :"));
xsdFileNames.add(new JTextField());
xsdBrowseButtons.add(new JButton("Browse"));
labels.add(xsdFileNames.get(labelCount - 1));
labels.add(xsdBrowseButtons.get(labelCount - 1));
frame.validate();
frame.pack();

if (null != xsdFileNames && !xsdFileNames.isEmpty())
for (int i = 0; i < xsdFileNames.size(); i++) {
final int j = i;
xsdBrowseButtons.get(i).addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
xsdFileNames.get(j).setText(
XMLUtils.chooseFile(filePath));
}
});
}
}
});

dynamicLabels.add(new JScrollPane(labels), BorderLayout.CENTER);

JButton validateButton = new JButton("Validate XML");
plafComponents.add(validateButton);
plafComponents.add(addNew);
plafComponents.add(errorMessage);
errorMessage.setForeground(Color.RED);

validateButton.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

if (xmlFileName.getText().isEmpty()) {
errorMessage.setText("XML File not selected");
errorMessage.setVisible(true);
viewUI();
} else if (null != xmlFileName.getText()
&& !XMLUtils.validateFileExtn(xmlFileName.getText(),
"xml")) {
errorMessage.setText("Invalid XML File selected");
errorMessage.setVisible(true);
viewUI();
} else if (xsdFileNames.isEmpty()) {
errorMessage.setText("XSD File(s) not selected");
errorMessage.setVisible(true);
viewUI();
} else {
for (JTextField xsdFileName : xsdFileNames) {
if (xsdFileName.getText().isEmpty()) {
errorMessage.setText("XSD File not selected");
errorMessage.setVisible(true);
viewUI();
} else if (null != xsdFileName.getText()
&& !XMLUtils.validateFileExtn(
xsdFileName.getText(), "xsd")) {
errorMessage.setText("Invalid XSD File selected");
errorMessage.setVisible(true);
viewUI();
} else {
System.out.println("Files Selected properly");
System.out.println("XML ::" + xmlFileName.getText());
System.out.println("XSD ::" + xsdFileName.getText());
errorMessage.setVisible(false);
validate = true;
}

}
}

if (validate) {
xsdStringFileNames=new ArrayList<String>();
for (JTextField xsdFileName : xsdFileNames) {
xsdStringFileNames.add(xsdFileName.getText());
}
validateXml(xmlFileName.getText(), xsdStringFileNames);
StringBuffer output = new StringBuffer();
if (exceptions.isEmpty()) {
output.append("Validation Completed Successfully");
JOptionPane.showMessageDialog(null, output, "Message",
JOptionPane.PLAIN_MESSAGE);
} else {
for (String excp : exceptions) {
output.append(excp + "\n");
}
JOptionPane.showMessageDialog(null, output, "Message",
JOptionPane.ERROR_MESSAGE);
}

}
}
});

frame.setContentPane(myPanel);
frame.pack();
frame.setLocationRelativeTo(null);
try{
frame.setLocationByPlatform(true);
frame.setMinimumSize(frame.getSize());
}
catch(Throwable t)
{

}
frame.setVisible(true);
}
}