validator.java

java web services how to program

// Validator.java
// Validate an XML document against its DTD.
package com.deitel.jws1.xml;

// Java core packages
import java.io.*;

// Java extension packages
import org.w3c.dom.*;
import org.xml.sax.*;
import javax.xml.parsers.*;

public class Validator {
      
   public static void main( String args[] )
   {   
      // check command-line arguments for file name
      if ( args.length != 1 ) {
         
         // print usage information
         System.err.println( 
            "Usage: java Validator filename" );
         
         System.exit( 1 );
      }      
      
      // create parser and parse given Document
      try { 
         
         // get a DocumentBuilderFactory for creating
         // a DocumentBuilder (i.e., an XML parser)
         DocumentBuilderFactory factory = 
            DocumentBuilderFactory.newInstance();
         
         // enable document validation
         factory.setValidating( true );     

         // get a DocumentBuilder from the DocumentBuilderFactory
         DocumentBuilder builder = factory.newDocumentBuilder();
         
         // set custom error handler
         builder.setErrorHandler( new MyErrorHandler() );

         // parse an XML document and create a DOM tree in 
         // memory
         Document messageDocument = 
            builder.parse( new File( args[ 0 ] ) );
         
         System.out.println( "Document is valid." );
      
      } // end try
      
      // handle exception creating parser
      catch ( ParserConfigurationException parserException ) { 
         System.err.println( "Error creating parser: " );
         parserException.printStackTrace(); 
      } 
         
      // handle exception parsing Document
      catch ( SAXException saxException ) { 
         System.err.println( "Error parsing Document: " );
         saxException.printStackTrace(); 
      }
         
      // handle exception reading data from Document
      catch ( IOException ioException ) { 
         System.err.println( "Error reading XML Document: " );
         ioException.printStackTrace(); 
      }   
   }
}

class MyErrorHandler implements ErrorHandler
{
   // throw SAXException for fatal errors
   public void fatalError( SAXParseException fatalException )
      throws SAXException
   {
      throw fatalException;
   }

   // throw SAXParseException for fatal errors
   public void error( SAXParseException errorException )
      throws SAXParseException
   {
      throw errorException;
   }

   // print warnings to System.err
   public void warning( SAXParseException warn )
      throws SAXParseException
   {
      System.err.println( warn.getMessage() );
   }
}

/*
 **************************************************************************
 * (C) Copyright 2003 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 **************************************************************************
*/