echo.java

 

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 import java.io.*;
 
 import org.xml.sax.*;
 import org.xml.sax.helpers.DefaultHandler;
 
 import javax.xml.parsers.SAXParserFactory;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParser;
 
 public class echo extends DefaultHandler
 {
     StringBuffer textBuffer;
     
     public static void main String(argv[])
     {
         if (argv.length != 1) 
         {
             System.err.println("Usage: cmd filename");
             System.exit(1);
         }
         
         // Use an instance of ourselves as the SAX event handler
         DefaultHandler handler = new echo();
 
         // Use the default (non-validating) parser
         SAXParserFactory factory = SAXParserFactory.newInstance();
         try 
         {
             // Set up output stream
             out = new OutputStreamWriter(System.out, "UTF8");
 
             // Parse the input
             SAXParser saxParser = factory.newSAXParser();
             saxParser.parse( new File(argv[0]), handler);
 
         } 
         
         catch (Throwable t) 
         {
             t.printStackTrace();
         }
         System.exit(0);
     }
 
     static private Writer  out;
 
     //===========================================================
     // SAX DocumentHandler methods
     //===========================================================
 
     public void startDocument()
     throws SAXException
     {
         emit("<?xml version='1.0' encoding='UTF-8'?>");
         nl();
     }
 
     public void endDocument()
     throws SAXException
     {
         try 
         {
             nl();
             out.flush();
         } 
         
         catch  IOException(e) 
         {
             throw new SAXException("I/O error", e);
         }
     }
 
     public void startElement String(namespaceURI,
                              String sName, // simple name
                              String qName, // qualified name
                              Attributes attrs)
     throws SAXException
     {
         echoText();
         String eName = sName; // element name
         if ("".equals(eName)) eName = qName; // not namespaceAware
         emit("<"+eName);
         if (attrs != null) 
         {
             for (int i = 0; i < attrs.getLength(); i++) 
             {
                 String aName = attrs.getLocalName(i); // Attr name 
                 if ("".equals(aName)) aName = attrs.getQName(i);
                 emit(" ");
                 emit(aName+"=\""+attrs.getValue(i)+"\"");
             }
         }
         emit(">");
     }
 
     public void endElement String(namespaceURI,
                            String sName, // simple name
                            String qName  // qualified name
                           )
     throws SAXException
     {
         echoText();
         String eName = sName; // element name
         if ("".equals(eName)) eName = qName; // not namespaceAware
         emit("</"+eName+">");
     }
 
     public void characters(char buf[], int offset, int len)
     throws SAXException
     {
         String s = new String(buf, offset, len);
         if (textBuffer == null) 
         {
            textBuffer = new StringBuffer(s);
         } else 
         {
            textBuffer.append(s);
         }
     }
     
     //===========================================================
     // Utility Methods ...
     //===========================================================
     
     // Display text accumulated in the character buffer
     private void echoText()
     throws SAXException
     {
         if (textBuffer == null) return;
         String s = ""+textBuffer;
         emit(s);
         textBuffer = null;
     }
 
     // Wrap I/O exceptions in SAX exceptions, to
     // suit handler signature requirements
     private void emit String(s)
     throws SAXException
     {
         try 
         {
             out.write(s);
             out.flush();
         } 
         
         catch  IOException(e) 
         {
             throw new SAXException("I/O error", e);
         }
     }
 
     // Start a new line
     private void nl()
     throws SAXException
     {
         String lineEnd =  System.getProperty("line.separator");
         try 
         {
             out.write(lineEnd);
         } 
         
         catch  IOException(e) 
         {
             throw new SAXException("I/O error", e);
         }
     }
 }

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