// DataBase.java
import java.sql.*;

public class DataBase {

  private static final String driverName = "org.gjt.mm.mysql.Driver";
  private String url   = "jdbc:mysql://gold.mcs.csuhayward.edu:3306/"; 
  private String dbuser;
  private String dbpass;
  private String dbname;
  private Connection con;
  private Statement stmt;
  private ResultSet rs; 
  
  // for tools such as JavaScript1.2 that cannot catch exceptions
  private boolean err   = false;
  private String errMsg = "";
  private boolean doCatch = false; 
  
  public DataBase(String name, String user, String password, boolean doCatch) throws Exception {
    err = false;
    this.doCatch = doCatch;
    try {
      dbuser = user; 
      dbpass = password;
      dbname = name;
      url = url + dbname; 
      //Class.forName(driverName);
      Class.forName(driverName).newInstance();
      con = DriverManager.getConnection(url,dbuser,dbpass);
    } catch (Exception e) {
      err = true;
      errMsg = e.getMessage();
      if (!doCatch) throw e;
    } 
  } 
  
  public DataBase(String name, String user, String password) throws Exception {
    this(name,user,password,false);
  }

  public ResultSet execute(String query) throws Exception {
    err = false;
    rs = null;
    try {
      stmt = con.createStatement();
      stmt.execute(query);
      rs = stmt.getResultSet(); 
    } catch (Exception e) { 
        if (e.getMessage().equals("mysql exception: No columns returned."))
          ; // JDBC driver bug - update was OK really 
        else {
          err = true;
          errMsg = e.getMessage();
          if (!doCatch) throw e;
        }
      }
    return rs;
  }

  public int executeUpdate(String query) throws Exception {
    err = false;
    int i = -1;
    try {
      stmt = con.createStatement();
      i =  stmt.executeUpdate(query);
    } catch (Exception e) {
        err = true;
        errMsg = e.getMessage();
        if (!doCatch) throw e;
      }
    return i; 
  }

  public void close() {
    try {
      rs.close();
      stmt.close();
      con.close();
    } catch (Exception e) {}
  } 

  public boolean hasError() {
    return err;
  }

  public String getErrMsg() {
    return errMsg;
  }

  // static methods

  public static double toDouble(String s) {
  Double d = new Double(0.0);
    try {
      d = Double.valueOf(s);
    } catch(Exception e) {return 0.0;}
    return d.doubleValue(); 
  }
  
  public static int toInt(String s) {
  Integer i = new Integer(0); 
    try {
      i = Integer.valueOf(s);
    } catch(Exception e) {return 0;}
    return i.intValue(); 
  }
  
  public static int max(int i, int j) {
    if (i > j)
      return i;
    else
      return j;
  }

  public static String getRow(ResultSet rs, ResultSetMetaData md, boolean getNames) {
  boolean padLeft;
  String d;
    try {
      String s = "";
      String s1 = "";
      for (int i=1; i<=md.getColumnCount(); i++) {
        String name = md.getColumnName(i);
        String d1 = "";
        if (getNames)
          d = name;
        else {
          d = rs.getString(i);
          if (d == null) d = "NULL";
        }
        int len = max(md.getColumnDisplaySize(i),
                      name.length());
        String type = md.getColumnTypeName(i);
        if (type.equals("INTEGER") || type.equals("FLOAT") || type.equals("DOUBLE"))
          padLeft = true;
        else
          padLeft = false; 
   
        if (getNames) {
          d = pad(d,len," ",padLeft);
          d1 = pad(d1,len,"-",padLeft);
        } else
          d = pad(d,len," ",padLeft); 
        
        s = s + d + " ";
        if (getNames) s1 = s1 + d1 + " "; 
      }
      if (getNames) s = s + "\n" + s1;
      return s; 
    } catch( Exception e ) {return e.getMessage();}
  }

  public static String pad(String s, int width, String padChar, boolean padLeft) {
    for (int i=s.length()+1; i<=width; i++)
      if (padLeft)
        s = padChar + s;
      else 
        s = s + padChar;
    return s;
  }

}