package  validator;

 import  java.io.File;
 import  java.io.IOException;

 import  java.awt.BorderLayout;
 import  java.awt.Dimension;
 import  java.awt.GridBagConstraints;
 import  java.awt.GridBagLayout;
 import  java.awt.Insets;
 import  java.awt.Toolkit;
 import  java.awt.Container;
 import  java.awt.event.ActionEvent;
 import  java.awt.event.ActionListener;

 import  javax.swing.JFileChooser;
 import  javax.swing.JFrame;
 import  javax.swing.JLabel;
 import  javax.swing.JPanel;
 import  javax.swing.JScrollPane;
 import  javax.swing.JTextArea;
 import  javax.swing.JTextField;
 import  javax.swing.ScrollPaneConstants;
 import  javax.swing.JButton;
 import  javax.swing.BorderFactory;
 import  javax.swing.border.Border;

 import  javax.xml.XMLConstants;
 import  javax.xml.parsers.DocumentBuilder;
 import  javax.xml.parsers.DocumentBuilderFactory;
 import  javax.xml.parsers.ParserConfigurationException;
 import  javax.xml.transform.dom.DOMSource;
 import  javax.xml.validation.Schema;
 import  javax.xml.validation.SchemaFactory;
 import  javax.xml.validation.Validator;

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

 public   final   class  XMLValidator {

     private   static   final  String GUI_INTERFACE_COMMAND = "-gui";
    
     public   static   void  main(String[] args) {
         if (args.length >  0 ) {
             if (args[ 0 ].equalsIgnoreCase(GUI_INTERFACE_COMMAND)) {
                 showGUIInterface();                                
            }
             else  {
                  try  {
                    File xmlFile =  new  File(args[ 0 ]);
                    File xmlSchemaFile =  new  File(args[ 1 ]);
                    processing(xmlFile, xmlSchemaFile);
                    System.out.println("Document is valid");
                 }
                  catch (Exception e) {
                    System.out.println(e.getMessage());
                 }
            }
        }
         else  {
            System.out.println("Wrong input parameters");
            System.out.println("The first parameter must be XML Document and the second - XML Schema");
            System.out.println("You may use GUI by specifing " + GUI_INTERFACE_COMMAND + " key");
        }       
    }

     private   static   void  showGUIInterface()
    {
         final  JFileChooser fileChooser =  new  JFileChooser();
        fileChooser.setFileFilter( new  javax.swing.filechooser.FileFilter() {
             public   boolean  accept(File file) {
                String fileName = file.getName();
                 return  file.isFile() && (fileName.endsWith("xml") || fileName.endsWith("xsd"));
            }
            
             public  String getDescription() {
                 return  "XML Documents & Schemas";
            }
        });
        
         final  JTextArea logTextArea =  new  JTextArea();
        logTextArea.setLineWrap(true);
        logTextArea.setWrapStyleWord(true);

         final  JFrame frame =  new  JFrame("Quick XML Validator");     
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
         final   int  FRAME_WIDTH =  496 ;
         final   int  FRAME_HEIGHT =  282 ;

        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Dimension screenDimension = toolkit.getScreenSize();

         int  screenWidth = ( int ) screenDimension.getWidth();
         int  screenHeight = ( int ) screenDimension.getHeight();
        
        frame.setBounds((screenWidth - FRAME_WIDTH) /  2 ,
                        (screenHeight - FRAME_HEIGHT) /  2 ,
                        FRAME_WIDTH,
                        FRAME_HEIGHT);

        GridBagLayout gridBagLayout =  new  GridBagLayout();
        GridBagConstraints gridBagConstraints =  new  GridBagConstraints();
        gridBagConstraints.fill = GridBagConstraints.BOTH;
        gridBagConstraints.insets =  new  Insets( 2 ,  2 ,  1 ,  1 );
        gridBagConstraints.weightx =  0 ;        

         final   int  FILE_TEXT_FIELD_SIZE =  25 ;        

        Border emptyBorder = BorderFactory.createEmptyBorder( 7 ,  7 ,  7 ,  7 );
        
        
        JPanel componentsPanel =  new  JPanel(gridBagLayout);
        componentsPanel.setBorder(emptyBorder);
        
        JLabel xmlFileLabel =  new  JLabel("XML File:");
        gridBagLayout.addLayoutComponent(xmlFileLabel, gridBagConstraints);
        componentsPanel.add(xmlFileLabel);
        
         final  JTextField xmlTextField =  new  JTextField(FILE_TEXT_FIELD_SIZE);        
        xmlTextField.setMinimumSize(xmlTextField.getPreferredSize());
        gridBagLayout.addLayoutComponent(xmlTextField, gridBagConstraints);
        componentsPanel.add(xmlTextField);
        
        JButton chooseXMLFileButton =  new  JButton("Choose...");
        gridBagConstraints.gridwidth = GridBagConstraints.REMAINDER;
        gridBagLayout.addLayoutComponent(chooseXMLFileButton, gridBagConstraints);        
        componentsPanel.add(chooseXMLFileButton);        
        chooseXMLFileButton.addActionListener( new  ActionListener()
                                              {
                                                     public   void  actionPerformed(ActionEvent event)                                                    {
                                                         int  openResult = fileChooser.showOpenDialog(frame);
                                                         if (openResult == JFileChooser.APPROVE_OPTION) {
                                                            xmlTextField.setText(fileChooser.getSelectedFile().getPath());
                                                        }
                                                         else   if (openResult == JFileChooser.ERROR_OPTION) {
                                                            logTextArea.setText("error occured while opening xml file");
                                                        }                                                        
                                                    }
                                              });
        
        
        JLabel xmlSchemaLabel =  new  JLabel("XML Schema File: ");
        gridBagConstraints.gridwidth =  1 ;
        gridBagLayout.addLayoutComponent(xmlSchemaLabel, gridBagConstraints);
        componentsPanel.add(xmlSchemaLabel);
        
         final  JTextField xmlSchemaTextField =  new  JTextField(FILE_TEXT_FIELD_SIZE);        
        xmlSchemaTextField.setMinimumSize(xmlSchemaTextField.getPreferredSize());
        gridBagLayout.addLayoutComponent(xmlSchemaTextField, gridBagConstraints);
        componentsPanel.add(xmlSchemaTextField);
        
        JButton chooseXMLSchemaFileButton =  new  JButton("Choose...");
        gridBagConstraints.gridwidth = GridBagConstraints.REMAINDER;
        gridBagLayout.addLayoutComponent(chooseXMLSchemaFileButton, gridBagConstraints);
        componentsPanel.add(chooseXMLSchemaFileButton);
        chooseXMLSchemaFileButton.addActionListener( new  ActionListener()
                                                    {
                                                         public   void  actionPerformed(ActionEvent event)                                                    {
                                                             int  openResult = fileChooser.showOpenDialog(frame);
                                                             if (openResult == JFileChooser.APPROVE_OPTION) {
                                                                xmlSchemaTextField.setText(fileChooser.getSelectedFile().getPath());
                                                            }
                                                             else   if (openResult == JFileChooser.ERROR_OPTION) {
                                                                logTextArea.setText("error occured while opening xml file");
                                                            }                                                        
                                                        }
                                                    });

        
        JButton validateButton =  new  JButton("Validate");
        gridBagConstraints.fill = GridBagConstraints.VERTICAL;
        gridBagConstraints.gridwidth = GridBagConstraints.REMAINDER;
        gridBagConstraints.insets =  new  Insets( 11 ,  0 ,  11 ,  0 );
        gridBagLayout.addLayoutComponent(validateButton, gridBagConstraints);
        componentsPanel.add(validateButton);        
        validateButton.addActionListener( new  ActionListener()
                                         {
                                             public   void  actionPerformed(ActionEvent event) {
                                                File xmlFile =  new  File(xmlTextField.getText());
                                                File schemaFile =  new  File(xmlSchemaTextField.getText());
                                                 try  {
                                                    processing(xmlFile, schemaFile);
                                                    logTextArea.setText("Document is valid");
                                                }
                                                 catch (Exception e) {
                                                   logTextArea.setText(e.getMessage());
                                                }                                                
                                            }                                            
                                        });
                
        gridBagConstraints.insets =  new  Insets( 2 ,  2 ,  1 ,  1 );
        
        JScrollPane textAreaScrollPane =  new  JScrollPane(logTextArea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED , ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER );
        gridBagConstraints.fill = GridBagConstraints.BOTH;        
        gridBagConstraints.weighty  =  1 ;
        gridBagConstraints.gridwidth = GridBagConstraints.REMAINDER;        
        gridBagLayout.addLayoutComponent(textAreaScrollPane, gridBagConstraints);
        componentsPanel.add(textAreaScrollPane);
        
        Container contentPane = frame.getContentPane();
        contentPane.add(componentsPanel, BorderLayout.CENTER);
               
        frame.setVisible(true);             
    }


     private   static   void  processing(File xmlFile, File schemaFile)  throws  Exception {
            Document xmlDocument = getXMLDocument(xmlFile);
            Validator schemaValidator = getSchemaValidator(schemaFile);
            DOMSource domSource =  new  DOMSource(xmlDocument);
            schemaValidator.validate(domSource);
    }
    
     private   static  Document getXMLDocument(File xmlFile) 
                               throws  ParserConfigurationException, 
                                 IOException,
                                 SAXException {
        
        DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
        domFactory.setNamespaceAware(true);         
        DocumentBuilder docBuilder = domFactory.newDocumentBuilder();
        Document xmlDocument = docBuilder.parse(xmlFile);
        
         return  xmlDocument;
    }

     private   static  Validator getSchemaValidator(File schemaFile) 
                                 throws  SAXException {
        
        SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
        Schema schemaObj = factory.newSchema(schemaFile);
        Validator validator = schemaObj.newValidator();
        
         return  validator;
    }
    
}