JSP design issue

I am working on an application, which is used by data entry people to enter approx 600 invoices/day thru web.
The requirement is that the data entered should be saved in the database and a unique number should be generated and displayed to the user almost instantaneously as the user cannot wait longer for response. EJBs are used for persistence and db is oracle. I am afraid if I make a trip to database and get the number from the db, the response time could be more. Does anybody have ideas on how to implement this. Greatly appreciate any inputs.

http://forum.java.sun.com/thread.jsp?forum=4&thread=210676

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Jsp performance issue on Safari

Hi,
We are facing performance issues while loading a jsp page in Safari browser on Macintosh.It takes around 2 minutes to load.
The same page used to take around 5 seconds on Netscape on Macintosh.
Have anyone faced a similar issue?
I'm new to jsp, so could you please provide some tips on how we can debug what is causing the issue and tune this?
Thanks,
Mini

On many projects I've worked on, including non-JDev, a general user interface rule was that you don't use an LOV if there's much more than 20-30 items. Think of this from a USER standpoint.
Note also that in Swing/DACF the combobox does NOT allow you to type the letters "starting" and automatically jump to the right place.. ( i.e. Enter WI in a state list doesn't take you to WISCONSIN ). This is a Sun JDK issue. ( Or has it changed in 1.3 in some manner... or is there a property set to allow this? )
As such, you've more a application design issue than a performance issue.
Good Luck
null

JSP design

Hello Everyone,
Hope ye are all well.
Well I have been asked asked to develop a JSP project. Basically I just have to design a few configuration pages for one of our products here. I am not very comfortable with my JSP experience when it comes to design issues. I was wondering if anyone can recommend a good book/website for designing JSPs.
I will need answers to solutions such as:
1. How to handle DB connections that are needed in a JSP
2. How to send objects from JSPs to some other server side class e.g. do I use the session?
3. How should my JSP be formatted.? How much Java code is too much? How do I seperate the logic from the presentation.?
Thanks alot folks,
Joyce

1. How to handle DB connections that are needed in a
JSPIMHO, database connections and transactions should be best kept away from JSPs/servlets. A good design should never mix the database querying logic with the View of the MVC. It can be done by means of an EJB, which would be rather heavy for most purposes, or plain DAOs.
http://java.sun.com/blueprints/corej2eepatterns/Patterns/DataAccessObject.html
2. How to send objects from JSPs to some other server
side class e.g. do I use the session?Session is one mechanism, which is generally preferred since it is quite fast and it can hold a fairly large quantity of data. For simple String data, even hidden fields and cookies can be utilized.
3. How should my JSP be formatted.? How much Java
code is too much? How do I seperate the logic from
the presentation.?IMO, JSPs should only contain logic for displaying the results on a nice GUI. AS far as linking it to business logic is concerned, it should pass through a controller, which can be a simple servet or a group of servlets with plain Java classes. But the business logic needs to be kept separate from the view for managing the changes to the requirements of your application at a later stage.
You could always have a look at the core J2EE patterns and choose the ones which seem appropriate for your requirement.
$

Design issue with the multiprovider

Design issue with the multiprovider :
I have the following problem when using my multiprovider.
The data flow is like this. I have the info-objects IobjectA, IobjectB, IobjectCin my Cube.(Source for this data is s-systemA)
And from another s-system I am also loading the masterdata for IobjectA
Now I have created the multiprovider based on the cube and IobjectA.
However, surprisingly join in not workign in multiprovider correctly.
Scenario :
Record from the Cube.
IObjectA= 1AAA
IObjectB = 2BBB
IObjectC = 3CCC
Records from IobjectA =1AAA.
I expect the record should be like this :
IObjectA : IObjectB: IObjectC
1AAA       :2BBB       :3CCC
However, I am getting the record like this:
IObjectA : IObjectB: IObjectC
1AAA       :2BBB       :3CCC
1AAA         : #             :#
In the Identification section I have selected both the entries for IobjectA still I am getting this error.
My BW Version is 3.0B and the SP is 31.
Thanks in advance for your suggestion.

May be I was not clear enough in my first explanation, Let me try again to explain my scenario:
My Expectation from Multi Provider is :
IObjectA
1AAA
(From InfoObject)
Union
IObjectA     IObjectB     IObjectC
1AAA     2BBB     3CCC
(From Cube)
The record in the multiprovider should be :
IObjectA     IObjectB     IObjectC
1AAA     2BBB     3CCC
Because, this is what the Union says .. and the Definition of the multiprovider also says the same thing :
http://help.sap.com/saphelp_bw30b/helpdata/EN/ad/6b023b6069d22ee10000000a11402f/frameset.htm
Do you still think this is how the behaviour of the multiprovider.. if that is the case what would be the purpose of having an infoobject in the multiprovider.
Thank you very much in advance for your responses.
Best Regards.,
Praveen.

Data mart from two DSOs to one - Loosing values - Design issue

Dear BW experts,
I´m dealing with a design issue for which I would really appreciate any help and suggestions.
I will be as briefly as possible, and explain further based on the doubts , questions I received in order to make it easier go through this problem.
I have two standard DSOs (DSO #1 and #2) feeding a third DSO (DSO #3), also standard.
Each transformation DOES NOT include all fields, but only some of them.
One of the source DSO (let´s call it DSO #1) is uploaded with a datasource that allows reverse type of records (Record Mode = 'R'). Therefore some updates on DSO #1 comes with one entry with record mode 'R' and a 2nd entry with record mode = 'N' (new).
Both feeds are delta mode, and not the same entries are updated through each of them, but the entries that are updated can differ (means an specific entry (unique key values) could be update by one of the feeds, but no updates on the 2nd feed for that entry).
Issue we have: When a 'R' and 'N' entries happen in DSO #1 for any entry, that entry is also reversed and re created in the target DSO #3 (even being that not ALL fields are mapped in the transformation), and thefore we loose ALL the values that are exclusively updated through DSO #2, becoming blank.
I don´t know it we are missing something in our design, or how should we fix this issue we have.
Hope I was more or less clear with the description.
´d really appreciatted your feedback.
Thanks!!
Gustavo

Hi Gustavo
Two things I need to know.
1. Do you have any End Routine in your DSO? If yes, what is the setting under "Update behavior of End Routine Display"....Option available right side of Delete Button ater End Rouine.
2. Did you try with Full Load from DSO1 and DSO2 to DSO3? Do you face the same problem?
Regards
Anindya

Design issue with sharing LV2 style global between run-time executables

Hi,
Just when I though that I had everything figured out, I ran into this design issue.
The application that I wrote is pretty much a client-server application where the server publishes data and the client subscribes data using data sockets. Once the client gets all the data in the mainClient.vi program, I use LV2 style (using shift registers) to make the data global to all the other sub-vi’s. So the LV2 is in initialize mode in the mainClient.vi program and then in the sub-vi’s the LV2 is in read mode. Also, I had built the run time menu for each sub-vi that when an item is selected from the menu, I would use the get menu selection to get the item tag which will be the file nam
e of the sub-vi and open the selected sub-vi using vi server. This all worked great on my workstation where I have labVIEW 7.0 Express installed. But the final goal is to make exe’s for each of these sub-vi’s and install runtime on the PC’s that do not have labVIEW installed. Of course when I did that only the mainClient.exe program was getting the updated data from the server but the sub-vi’s were not getting the data from the mainClient.exe. I did realize that the reason for this is due to the fact that I had compiled all the sub-vi’s separately and so the LV2 vi is now local to each executable (i.e. all executables have their own memory location). Also, the run-time menu did not work because now I am trying to open an executable using vi server properties.
To summarize, is there a way to share LV2 style global's between executables without compiling all of the sub-vi’s at one time? I tried using data-sockets (local-host) instead of LV2 st
yle gloabls to communicate between the sub-vi’s but I ran into performance issues due to the large volume of data.
I would really appreciate it if anyone can suggest a solution/alternative to this problem.
Thanks
Nish

> 1) How would I create a wrap-around for the LV2.vi which is
> initialized in my mainClient.vi and then how would I use vi server in
> my sub-vi to refer to that LV2.vi?
> You mentioned that each sub-vi when opened will first connect to the
> LV2.vi via via-server and will keep the connection in the shift
> register of that sub-vi. Does this mean that the sub-vi is accessing
> (pass-by-reference) the shared memory of the mainClient.vi? If this
> is what you meant I think that this might work for my application.
>
If the LV2 global is loaded statically into your mainClient.vi, then any
other application can connect to the exe and get a reference to the VI
using the VI name. This gives you a VI reference you can use to call
the VI. Ye
s, the values will be copied between applications. That is
why you need to add access operations to the global that returns just
the info needed. If you need the average, do that in the global. If
you need the array size, do that in the global. Returning the entire
array shouldn't be a common operation on the LV2 style global anyway.
> 2) Just to elaborate on my application, the data is
> transferred via DataSockets from the mainServer.vi on another PC to
> the client’s PC where the mainClient.vi program subscribes the
> data (i.e. 5 arrays of double type and each arrays has about 50,000
> elements). The sub-vi’s will have to access these arrays
> located on the mainClient.vi every scan. Is there any limitation on
> referencing the mainClient.vi data via vi-server from each sub-vi?
Your app does need to watch both the amount of data being passed across
the network, and the amount being shared between the apps. You might
want to consider puttin
g the VIs back into the main app. What is the
reason you are breaking them apart for?
Greg McKaskle

A web service design issue with patterns

Hello,
I�d like to ask for your help in the following design issue:
I need to create an email sending web service (with Axis). Only just one method which returns with an integer return code. This handles the following:
- based on the given parameters gets the email addresses from an
LDAP server (with netscape ldap for java)
-     makes a cache from them (only after a timeout period will be the cache
refreshed) (don�t know what tool to use for this)
-     selects html templates which to be sent based on the given parameters
-     sends emails with the appropriate templates (with Velocity)
-     the whole process is logged (with log4j)
I have to write the code as generic as possible. I know that some design pattern should be used for this. (some from GoF , and I know there exists design patterns specially created for web services as well).
Could you enumerate me which patterns (and for what part of the program) would be the best choice to solve this problem? I have read through some books about patterns, but don�t have the knowledge to pick up the right one for a concrete problem like this..
Thank you in advance,
nagybaly

Hello,
I�d like to ask for your help in the following design
issue:
I need to create an email sending web service (with
Axis). Only just one method which returns with an
integer return code. This handles the following:Lots of responsibilities here. You would do well to break this up into several classes that you can test separately.
I would also advise that you not embed all this in a servlet. Make a service that collaborates with several objects to accomplish the task and let the serlvet just call it.
.> - based on the given parameters gets the email
addresses from an
LDAP server (with netscape ldap for java)I'd recommend Spring's LDAP module. Pretty terrific stuff.
cache from them (only after a timeout period will be
the cache
refreshed) (don�t know what tool to use for
this)Maybe EhCache or OsCache or something like that.
-     selects html templates which to be sent based on
the given parametersWhere does this come from? Certainly not the LDAP. A relational database? Write a DAO for the document template.
-     sends emails with the appropriate templates (with
Velocity)Have an e-mail sender service using Java Mail.
-     the whole process is logged (with log4j)Easily done.
I have to write the code as generic as possible. I
know that some design pattern should be used for
this. No pattern. There might be patterns, if you say that the DAOs to access the LDAP and RDB are patterns.
Stop thinking patterns and start thinking objects.
(some from GoF , and I know there exists design
patterns specially created for web services as
well).Nope.
Could you enumerate me which patterns (and for what
part of the program) would be the best choice to
solve this problem? I have read through some books
about patterns, but don�t have the knowledge to pick
up the right one for a concrete problem like this..
Thank you in advance,
nagybalyYou haven't read them because they aren't there. Your problem is pretty specific, even if it's common.
%

SOA Design issues and other politics

Hi all,
I have a requirement for live data feed from external system. I am using SOA11g and JDeveloper 11g. There are two designs, one proposed and other I have in mind to achieve this.
1) The external system sends XML data in a push model to the exposed SOA Web Service (uses one-way messaging mode) at my end. I then store the message in the database
a) In this design how do we keep track of all messages that are sent are received. Is there a better solution.
2) The third party is proposing a Web Service at their end. The application being real-time (i.e any changes at their DB end i.e some DB tables, should be propogated across to our web services using XML messages). I will have to keep sending XML requests on a regular basis (say every 5 seconds). Can I achieve such type of Web Service client using SOA 11g?
a) Here I have a design issue, that the data feed is live, why do the WS client have to keep sending requests at regular intervals. Why can't the third party send data whenever there is an update/insert at their database end. Third party is coming up with advantages like loose coupling and making the Web Service more generic. I doubt all the claims give that the applications are B2B and we are the other ones who will be using their web services for the time being. Their may be other two organizations later on.
b) If the first request is not yet returned, will the second request after 5 seconds be blocked.
This designs and solutions are becoming quite political across organizations, and got to do with who will take the blame for data issues. I just want a proper SOA design for live data feed. Please suggest the advantages and disadvantages of both if anybody has been through this path.
Thanks
Edited by: user5108636 on 1/09/2010 18:19

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/dynamic/advanced-wireless.html
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Design Issue: Localization using Lookup OR Dependency Injection

Hello Forums!
I'm having a design issue regarding localization in my application. I'm using Spring Framework (www.springframework.org) as an
application container, which provides DI (dependency injection) - but the issue is not Spring- but rather design related. All localization
logic is encapsulated in a separate class ("I18nManager"), which basically is just a wrapper around multiple Java ResourceBundles.
Right now localization is performed in the "traditional" look-up style, e.g.
ApplicationContext.getMessage("some.message.key");
where ApplicationContext is a wrapper around the Spring application context and getMessage(...) is a static method on that
context. The advantage of that solution is a clean & simple interface design, localization merely becomes a feature of classes, but
is not part of their public API. The only problem with that approach is the very tight coupling of Classes to the ApplicationContext, which
really is a problem when you want to use code outside of an application context. The importance of this problem increases if one considers
that I18N is a concern that can be found in every application layer, from GUI to business to data tier, all those components suddenly depdend
on an application context being present.
My proposed solution to this problem is a "Localizable" interface, which may provide mutators for an "I18NManager" instance that can be
passed in. But is this really a well-designed solution, as almost any object in an application may be required to implement this interface?
I'm too concerned about performance: the look-up solution does not need to pass references to localizable objects, whereas my proposed solution
will require 1 I18NManager reference per localizable object, which might cause troubles if you let's say load 10.000 POJOs from some database that
are all localizable.
So (finally) my question: how do you handle such design issues? Are there any other solutions out there that I'm not aware of yet? Comments/Help welcome!

michael_schmid wrote:
Hello Forums!
I'm having a design issue regarding localization in my application. I'm using Spring Framework (www.springframework.org) as an
application container, which provides DI (dependency injection) - but the issue is not Spring- but rather design related. All localization
logic is encapsulated in a separate class ("I18nManager"), which basically is just a wrapper around multiple Java ResourceBundles.Why do you think you need a wrapper around resource bundles? Spring does very well with I18N, as well as Java does. What improvement do you think you bring?
Right now localization is performed in the "traditional" look-up style, e.g.
ApplicationContext.getMessage("some.message.key");
where ApplicationContext is a wrapper around the Spring application context and getMessage(...) is a static method on that
context. Now you're wrapping the Spring app context? Oh, brother. Sounds mad to me.
The advantage of that solution is a clean & simple interface design, localization merely becomes a feature of classes, but
is not part of their public API. The only problem with that approach is the very tight coupling of Classes to the ApplicationContext, which
really is a problem when you want to use code outside of an application context. The importance of this problem increases if one considers
that I18N is a concern that can be found in every application layer, from GUI to business to data tier, all those components suddenly depdend
on an application context being present.One man's "tight coupling" is another person's dependency.
I agree that overly tight coupling can be a problem, but sometimes a dependency just can't be helped. They aren't all bad. The only class with no dependencies calls no one and is called by no one. We'd call that a big, fat main class. What good is that?
Personally, I would discourage you from wrapping Spring too much. I doubt that you're improving your life. Better to use Spring straight, the way it was intended. I find that they're much better designers than I am.
My proposed solution to this problem is a "Localizable" interface, which may provide mutators for an "I18NManager" instance that can be
passed in. But is this really a well-designed solution, as almost any object in an application may be required to implement this interface?I would say no.
I'm too concerned about performance: the look-up solution does not need to pass references to localizable objects, whereas my proposed solution
will require 1 I18NManager reference per localizable object, which might cause troubles if you let's say load 10.000 POJOs from some database that
are all localizable.
So (finally) my question: how do you handle such design issues? Are there any other solutions out there that I'm not aware of yet? Comments/Help welcome!I would use the features that are built into Spring and Java until I ran into a problem. It seems to me that you're wrapping your way into a problem and making things more complex than they need to be.
%

Design Issues, suggestions welcome

I have stumbled across some design issues, with a carhire system i am making.
          kept in
     [CAR]------------------->[GARAGE]
|
                    |
                    | Retives car from garage
|
|
|
                    [TIMESLOT]
As it stands the GARAGE class automatically has CAR objects added as attributes.
import java.util.*;
public class Garage {
     //class attributes
          private LinkedList carhold;
          Car ford_ka = new Car("A",135);
          Car ford_focus = new Car("B",149);
          Car ford_Mondeo = new Car("C",179);
           Car Vauxhall_Vectra = new Car("D",239);
          Car Mercedes_E240 = new Car("H",290);
          Car Renault_Espace = new Car("V",399);
     public Garage() {
          carhold = new LinkedList();
          carhold.add(ford_ka);
          carhold.add(ford_focus);
          carhold.add(ford_Mondeo);
          carhold.add(Vauxhall_Vectra);
          carhold.add(Mercedes_E240);
          carhold.add(Renault_Espace);          The TIMESLOT class has an GARAGE object as an attribute, thus enabling it access mehtods.
import java.util.*;
public class TimeSlot {
       Garage g = new Garage();
public void getCarCost(String input) {
           Car theCar = g.search(input);problem is each time a new TIMESLOT is create so too is a
new garage created with all the cars.
I really need the garage to be a seperate entity, but still allowing
the TIMESLOT class to use its methods.
would in heritence be the appropriate solution, or maybe something else.
I would like to hear other suggestions.

I believe a Singleton pattern works perfectly here. A singleton ensures that only one instance of an object is created. You would use it as follows:
public class Garage {
    private LinkedList carhold;
    // Car declarations here
    private Garage() {
        carhold = new LinkedList();
        // add cars here
    public static Garage getInstance() {
        static Garage instance = null;
        if (instance == null)
            instance = new Garage();
        return instance;
public class TimeSlot {
    public void getCarCost(String input) {
        Garage g = Garage.getInstance();
        // do some other stuff
}Notice the PRIVATE constructor on the Garage class. This keeps classes other than Garage from instantiating it. In fact, the only way to get an instance of Garage is to call Garage.getInstance(), which will always return the same instance.
You might also consider the Builder pattern, which will keep you from having to instantiate all those Car objects inside of your Garage. You would do something like this:
public class Garage {
    LinkedList carhold;
    public Garage() {
        carhold = new LinkedList();
    public void addCar(Car c) {
        carhold.add(c);
public class GarageBuilder {
    public static final int BOBS_GARAGE = 0;
    public static final int BILLS_GARAGE = 1;
    public static Garage buildGarage(int garage) {
        Garage g = new Garage();
        switch (garage) {
            case BOBS_GARAGE:
                Car c = new Car("bobsCar", 200);
                g.add(c);
                break;
            case BILLS_GARAGE:
                Car c = new Car("billsCar", 400);
                g.add(c);
                break;
        return g;
}

JSC2.1 Fedora5 and Chinese, jsp design view blank!!!

Dear all,
I can run JSC2.1 in Fedora 5 chinese language, but jsp design view is blank, I can not drop any componnent in it and cannot see anything., and if I change JSC2.1 to "-locale en", JSC2.1 is all Okay, please help me

If you get the designer blank, there is some bug. Could you have a look into your log file? It is <your_userdir>/var/log/messages.log? There should be some exceptions causing that state. Send them here or file bug directly.
In any case, try to workaround the problem by deleting <your_userdir> and restarting JSC.

JSP Design View in Linux?

Hi,
I've been going through the weblogic platform evaluation which uses workshop
heavily. One example which keeps coming up is using the "Design View" of the
JSP Designer. Unfortunately, I don't have a tab for this, nor do I find it in
any of the menus.
I'm running workshop under Gentoo Linux, which I know isn't an
officially supported Linux distro, but everything else in workshop seems to work.
Anyone have any ideas? Is this feature supported at all under Linux?
Thanks,
-Anthony

Unfortunately, in 8.1 Design View for JSPs is not supported on Linux.
This is being addressed in the next release.
Josh
Anthony Molinaro wrote:
Hi,
I've been going through the weblogic platform evaluation which uses workshop
heavily. One example which keeps coming up is using the "Design View" of the
JSP Designer. Unfortunately, I don't have a tab for this, nor do I find it in
any of the menus.
I'm running workshop under Gentoo Linux, which I know isn't an
officially supported Linux distro, but everything else in workshop seems to work.
Anyone have any ideas? Is this feature supported at all under Linux?
Thanks,
-Anthony

Security design issue

Hi Folks,
I've a security design issue using J2EE architecture framework in my
project..
Proj Requirement:
i) User Logs-into a health b2b/b2c portal website...
ii) Check the user exist in the database or LDAP directory service.
iii) If exist user then check the role Patient/Insurance Provider/Physician?
iv)If Patient then display his personal health record history.
else Insurance Provider then display about Insurance Policy information,
which he can update/create insurance for entered patient id. If patient has
granted access to Insurance Provider
and if Physician then display about hospital information like
waiting patients,sending appointments,etc..
The above security access control role & policy has to be implemented
very strong. so that other user cannot view/update someone health records..
Development tool:WebLogic Server/Oracle/LDAP.. on Linux
Security Problem:
i)What is the best security solution for the above requirement?
ii)How do I authenticate/validate user using J2EE security framework?
Can anyone explain in details or steps to implement?
Thanks,
-raj-

I'm assuming that your using WLS 6, if so check out (I know we cover this in
the documentation but I'm guessing at the title) the "securing your site"
guide. Some of what you're planning the WLS server can protect through good
ACL usage. I'd recommend creating at least three groups (patient, provider,
physician), clearly the danger lies in having a user who is a member of more
than one group. I'd recommend implementing your own role checking at both
the servlet and EJB levels to fully enforce information access, using
servlet state and stateful session beans should help.
Alex
Raj <[email protected]> wrote in message
news:[email protected]..
Hi Folks,
I've a security design issue using J2EE architecture framework in my
project..
Proj Requirement:
i) User Logs-into a health b2b/b2c portal website...
ii) Check the user exist in the database or LDAP directory service.
iii) If exist user then check the role Patient/InsuranceProvider/Physician?
iv)If Patient then display his personal health record history.
else Insurance Provider then display about Insurance Policy information,
which he can update/create insurance for entered patient id. If patienthas
granted access to Insurance Provider
and if Physician then display about hospital information like
waiting patients,sending appointments,etc..
The above security access control role & policy has to be implemented
very strong. so that other user cannot view/update someone healthrecords..
>
Development tool:WebLogic Server/Oracle/LDAP.. on Linux
Security Problem:
i)What is the best security solution for the above requirement?
ii)How do I authenticate/validate user using J2EE security framework?
Can anyone explain in details or steps to implement?
Thanks,
-raj-

Design issue - Historical data - referencial integrity

Hi,
I dont know if this is the right place to post this question, but
I would to like know about the design issues in storing historical data .
I have a historical table about events ( notifications, alarms, etc ).
In historical table would I store fields with foreign key to the master table ( device table ) ?
In this design , how handle then updates ( remove record ) to the master table ?
would I have a trigger to update the historical table too ? Or I mustn' t permit
updates in master table primary Keys ?
And about no store The foreign keys in the historical data ?
What are the disvantages of this model ?
Thank you,
Faria

Faria,
The answer depends on why you want historical data.
Is the historical data to be used for auditing or legal purposes?
Are you trying to move historical data for performance reasons?
Is there some other purpose?
If you're doing this for auditing purposes, I don't recommend using foreign keys since you won't easily be able to capture delete activity.
I mostly use Designer for all of our designs and typically will turn on server side journaling for this purpose. Designer will then generate the journaling tables and write the triggers to manage the whole process. You don't even need to be a programmer to figure it out.
Let me know back if this isn't your purpose or you need clarification.
Thanks, George

Design issue using JFrame, JPanel, JLabel

I have been working on this problems for several months now and I and nearly finished.
I have a design question I hope others from this forum can provide some incite to the best approach.
The problem space is a 8 X 8 Chessboard. I have designed a board using JPanels and JLables sitting inside a JFrame. In each square on the chessboard is a JLabel with an image. The "board" sits in the DEFAULT LAYER of a JLayeredPane. As the user clicks a specific square, a queen is placed in the square (8-queens problem). The only thing I do is swap out the image. All this works well--thanks to several of you from this forum. :-)
When I add a new queen to the board, the application goes through the evaluation of attack positions. Next, the application should display the new chessboard with only the queens not threaten by other queens. I keep up with the chessboard using an boolean array internally. I build a second boolean array for the new or refreshed chessboard.
What I want to do is build a second chessboard and "swap" it out with the one in the default layered pane. Can someone be so kind and shine some light on this design issue for me?
Thank you for taking the time to read my post.

I don't understand this approach. Swing is by default 'double buffered' and will not flicker. You will get this be default since this is one of the things the Swing painting model gives over AWT.
You should look at just using JComponent and the paintComponent() method for drawing what you need.
What I've done in the past is have a simple XML JDoM model. Have components that render themselves based on this model.
Changing the model then I just issues a call to repaint() at the top level container.
You can also add and remove items from the parent container. Then issue validate() or repaint(). Can't remember now but I think validate() hits the layout manager logic and then repaints.
I'm pretty sure the Romain guy posted an example of how to easily draw a background chess board in a panel. ;-)
The tree concept might really prove useful for a 'gaming tree' approach at the AI also.
If you look at the Java3D API you will see they use a tree to represent what is rendered and the details about it. Really nice until you change something in the tree that cause the renderer to blow up. ;-)
I guess the moral is always make small simple changes and test.
Hope this is helpful.

JSP design issue

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