Hi, How much data you expect from your select boxes ?? If it is a small amount, I would suggest that you store it in a Vector and save it as a application attribute. Then you static methods can "query" the Vector instead. You only need to update the Vector if there is any changes to the these select boxes' data (I presume that will not happen often)
HTH Best Regards, Lim Yong How Software Engineer Ryeson Security International 180B Bencoolen Street #10-01/02 The Bencoolen Singapore 189648 www.ryeson.com <http://www.ryeson.com> ____________________________________________________________________________ ________________________ The information contained in this e-mail message is intended only for the use of the person or entity to whom it is addressed and may contain information that is CONFIDENTIAL and may be LEGALLY PRIVILEGED and exempt from disclosure under applicable laws. If you read this message and are not the addressee you are notified that use, dissemination, distribution, or reproduction of this message is prohibited. If you have received this message in error, please notify us immediately and delete the original message. ____________________________________________________________________________ __________________ -----Original Message----- From: A mailing list about Java Server Pages specification and reference [mailto:[EMAIL PROTECTED]]On Behalf Of Kesavanarayanan, Ramesh (Cognizant) Sent: Friday, 20 December, 2002 12:56 PM To: [EMAIL PROTECTED] Subject: static initialization Hi all, I have a Helper class which has several methods. Each method willspeak overto the DB and get the values as ArrayList. These values will be loaded in the HTML pages as option values of the select boxes. Here is the sample code snippet i have used . I have made the OWNER_LIST as private static. private static ArrayList distinctOwner(String tableName) { Connection conn = null; PreparedStatement pstmt = null; DBUtilities DBUtil = null; if(OWNER_LIST == null) { try { OWNER_LIST = new ArrayList(); DBUtil = new DBUtilities(); conn.setAutoCommit(false);; String sql = "select distinct owner_name from " + tableName + " order by owner_name"; ResultSet rs = DBUtil.doSelect(sql); while (rs != null && rs.next()) { OWNER_LIST.add(rs.getString(1)); } rs.close(); } catch (Exception e) { System.err.println("Problem getting distinct owner from " + tableName + " order by owner name"); } finally { try { pstmt.close(); } catch (Exception e) { } try { DBUtil.closeConnection(); } catch (Exception e) { } } } return OWNER_LIST; } I have made all these ArrayList as static so that they will be populated only once in the server. Typically I amtrying to catch the records. Some transaction during the application may change the DB records. In such scenario i have to call a Refresh such that this makes all the values of the Helper class again to null so that when next time somebody clicks on some item Helper class has to fetch the new values from the DB. My question is supposing that when a user clicks on the Refresh buton and at the same time some other user is looping thru the ArrayList in their jsp pages, it will surely thro an error. How to prevent this. I thought of putting the ArrayList initialization as synchronized but in my Helper class i have many methods (25). That means i will be having 25 Synchronized blocks which might become too overhead for the webserver. Any nice ideas and suggestions to resolve this ishighly appreciated. Regards Ramesh Kesavanarayanan [EMAIL PROTECTED] +91-44- 811 3063 ext 2232 VNet- 42425 =========================================================================== 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://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com
