Thanks for your replies, Ron. But I think you did not quite understand
the kind of problem here. The problem is how to do the functionallity of the
code you wrote but without having to write another class like App1Constant
or App2Constant when you add another application to the server. More than
that... actually I want no change to code at all. This can be done, for
example, this way:
Have this start up code to run before anything else in the application:
getServletContext().setAttribute("Const", new
Constant(getServletContext()));
And at Constant do:
public Constant(ServletContext sc)
{
String fileNameToReadValues = sc.getRealPath("/constant.ini");
// read values from 'fileNameToReadValues'
}
This way, when adding another application, the same code may be used. Only
the constant.ini file in the new application will be different (because it
will contain the values the application will use). But there is a problem
doing this way: all classes that want access to Constant must have access to
ServletContext, because only that way they will obtain the right Constant
instance (through the getAttribute method). This problem can be worked out
by giving every class a reference to ServletContext. But I was asking if
anyone have a better solution for this problem than doing all these.
Rodrigo.
> -----Mensagem original-----
> De: Ron Chan [mailto:[EMAIL PROTECTED]]
> Enviada em: Segunda-feira, 9 de Abril de 2001 13:25
> Para: [EMAIL PROTECTED]
> Assunto: Re: Organizing Application Constants
>
>
> hi,
>
> something like:
>
>
> 1 import java.util.*;
>
> 2 public abstract class AbstractConstant
> 3 {
> 4 public final static int APP1 = 1;
> 5 public final static int APP2 = 2;
> 6 private final static String cdb =
> "currentDB";
> 7 private final static String DBURL =
> "dbURL";
>
> 8 public static class App1Constant extends
> AbstractConstant {
> 9 public App1Constant() {
> 10 super();
> 11 setDBUrl( rb.getString( DBURL + currentDB
> + APP1 ) );
> 12 }
> 13 }
> 14 public static class App2Constant extends
> AbstractConstant {
> 15 public App2Constant() {
> 16 super();
> 17 setDBUrl( rb.getString( DBURL + currentDB
> + APP2 ) );
> 18 }
> 19 }
>
> 20 private String dbURL = null;
> 21 private String rbString = "ac";
> 22 protected ResourceBundle rb = null;
> 23 protected String currentDB = null;
>
> 24 public AbstractConstant() {
> 25 rb = ResourceBundle.getBundle( rbString );
> 26 currentDB = rb.getString( cdb );
> 27 }
>
> 28 public void setDBUrl( String s ) {
> 29 this.dbURL = s;
> 30 }
> 31 public String getDBUrl() {
> 32 return this.dbURL;
> 33 }
> 34 public static AbstractConstant Create( int
> i ) {
> 35 AbstractConstant ap = null;
> 36 if( APP1 == i ) {
> 37 ap = new AbstractConstant.App1Constant();
> 38 }
> 39 else if( APP2 == i ) {
> 40 ap = new AbstractConstant.App2Constant();
> 41 }
> 42 return ap;
> 43 }
> 44 }
>
>
> 45 public class App1
> 46 {
> 47 private AbstractConstant abcon =
> AbstractConstant.Create( AbstractConstant.APP1 );
> 48 public App1() {
> 49 System.out.println( "1 dburl: " +
> abcon.getDBUrl() );
> 50 }
> 51 public static void main( String[] arg ) {
> 52 App1 ap = new App1();
> 53 }
> 54 }
>
>
> 55 public class App2
> 56 {
> 57 private AbstractConstant abcon =
> AbstractConstant.Create( AbstractConstant.APP2 );
> 58 public App2() {
> 59 System.out.println( "2 dburl: " +
> abcon.getDBUrl() );
> 60 }
> 61 public static void main( String[] arg ) {
> 62 App2 ap = new App2();
> 63 }
> 64 }
>
> 65 currentDB=oracle
> 66 dbURLpostgres1=something1
> 67 dbURLpostgres2=something2
>
> 68 dbURLoracle1=somethingElse1
> 69 dbURLoracle2=somethingElse2
>
> ron
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
