NYWC database through JDBC to Piped Reader

• Streaming solutions are often more efficent

• That's a big reason to use SAX instead of DOM

import java.sql.*;
import java.io.*;

public class BiosToReader implements Runnable {
  
  private Writer out;
  private Reader source;

  public Reader getReader() {
    return this.source; 
  } 
  
  private String userName;
  private String password;  // should be a char[] for security
  private String host = "luna.oit.unc.edu";
  private String database = "NYWC";
                                       
                                    
  public BiosToReader(String userName, String password) 
   throws IOException {
    
    this.userName = userName;
    this.password = password;
    
    PipedWriter out = new PipedWriter();
    this.source = new PipedReader(out);
    this.out = out;
    
  }
  
  //Requires JDBC MySQL Driver from http://www.worldserver.com/mm.mysql/
  private String driver = "org.gjt.mm.mysql.Driver";

  public void run() {
    
    try {
      
      Class.forName(driver).newInstance(); 
      
      // Connect to the database
      Connection connection = DriverManager.getConnection(
        "jdbc:mysql://" + host + "/" + database, userName, password);
                 
      Statement statement = connection.createStatement();
      ResultSet bios = statement.executeQuery(
       "SELECT * FROM composers ORDER BY ComposerLastName, ComposerFirstName");
      
      out.write("<?xml version=\"1.0\"?>\r\n");
      out.write("<Composers>\r\n");
       
      while (bios.next()) {
        
        out.write("  <Composer>\r\n");
        /* primary key */
        out.write("      <first>");
        out.write(bios.getString("ComposerFirstName"));
        out.write("</first>\r\n");
        out.write("      <middle>");
        out.write(bios.getString("ComposerMiddleName"));
        out.write("</middle>\r\n");
        out.write("    <name>\r\n");
        out.write("      <last>");
        out.write(bios.getString("ComposerLastName"));
        out.write("</last>\r\n");
        out.write("    </name>\r\n");
        
        /* These can be null */
        writeElement("biography", bios.getString("ComposerBio"));
        writeElement("email", bios.getString("ComposerEmail"));
        writeElement("url", bios.getString("ComposerURL"));
        writeElement("title", bios.getString("ComposerTitle"));
        
        // Omit these for privacy in this example
/*        writeElement("voice", bios.getString("ComposerVoice"));
        writeElement("fax", bios.getString("ComposerFax"));
        writeElement("street", bios.getString("ComposerStreet"));
        writeElement("suite", bios.getString("ComposerSuite"));  */
        writeElement("state", bios.getString("ComposerState"));
        writeElement("city", bios.getString("ComposerCity"));
        writeElement("country", bios.getString("ComposerCountry"));
        writeElement("zip", bios.getString("ComposerZip"));
        Date expires = bios.getDate("ComposerMembershipExpires");
        String expiresDate = null;
        if (expires != null) expiresDate = expires.toString();
        writeElement("expires", expiresDate);
        
        out.write("  </Composer>\r\n\r\n");
      }         

      out.write("</Composers>\r\n");
      out.flush();
                 
    }
    catch (Exception e) {
      System.err.println(e);
      e.printStackTrace();
    }
    
  }
  
  private void writeElement(String name, String content) 
   throws IOException {
    
    // would be straight-forward to omit null elements
    // rather than making them empty
    out.write('<' + name + '>');
    if (content != null) {
      char[] characters = content.toCharArray();
      for (int i = 0; i < characters.length; i++) {
        switch (characters[i]) {
          case '&':
            out.write("&amp;");
            break;
          case '<':
            out.write("&lt;");
            break;
          default:
            out.write(characters[i]); 
        }
      }
    }
    out.write("</" + name + ">\r\n");
    
  } 
  
  public static void main(String[] args) {
    
   try {
     BiosToReader btr = new BiosToReader(args[0], args[1]);
     Thread t = new Thread(btr);
     t.start();
     Reader in = btr.getReader();
     int c;
     try {
       while ((c = in.read()) != -1) System.out.write(c);
     }
     catch (IOException e) {
       // Write end dead
     }
   } 
   catch (ArrayIndexOutOfBoundsException e) {
     System.out.println("Usage: java BiosToReader username password");
   }
   catch (Exception e) {
     System.err.println(e);
     e.printStackTrace();
   }
   
  }
  

}