hi ..i am working on a project that i am trying my best to design it as OO as possible ..i have the core of the system as a class called Gipsy, it instansiates a factory which instanciate an interface which is being implemented by a text interface(TInter) and GUI interface(GInter).now my ...

Hi, normally I use the code below. But I experiencedthat if I call getRefernce more than once from a staticcontext the constructor is called more than once, but that isn't the intend way it should work.The lines I added reduces the problem, but I don't think that's the wa it should work. I ...

What do you mean when you say that in the MVC architecture multiple views are caterred to by the same model . Kindly explain this if you can achieve this with MVC ?

hi,Can anyone tell me the class diagrams of a simple java notepad.i'm a very beginner in UML.thanks in advance.Moazzam

hi there.I am currently working on a college project and it should be using OO Design, I got a problem to design a class diagram and not sure how to apply MVC on this API project.what i got so far is.Data classes - this is a set of data classes.1) DataSetGroup2) DataSet3) DataInAPI classes - ...

For example, I need 2 classes having the same methods but working with different object types. Should I write the same code twice?interface I { getValue(); setValue(value);}class A implements I { Integer value; Integer getValue() { return value; } setValue(Integer value) { this.value = value; ...

I constantly hear about Java replacing C++. Simple as it sounds, I do not find it easy to use Java for simple/small tools like the one that I am looking at. Any suggestion to re-design this tool using Java/jdbc/jsp/... will be helpful.A Simple tool that takes input from a text file and changes ...

How do I map my business classes that implement inheritance to my DAO layer?Do I create a single DAO to my class hierarchy?Do I inherit one DAO from another one?Or what?

How do I map my business classes that implement inheritance to my DAO layer?Do I create a single DAO to my class hierarchy?Do I inherit one DAO from another one?Or what?

Lets say I want all subclasses of a certain class to be created through a factory. I want to disallow instantiation of subclasses through direct instantiation using "new" .How can I enforce that? I would like the baseclass to enforce this, so that it should not be possible to define subclasses ...

I am starting a Java project that has web and desktop interfaces. I am designing a multi layer solution like:- persistence layer (PL)- business rules layer (BL)- UI layer (UI)I strongly want to reuse PL and BL, independent of wich UI I am.Should I use Java Beans as BL or PL? EJB?What about MVC ...

Hi,I'm new to j2EE as you may cater from the question.The question is, should Entity beans and Database tables be a 1 to 1 relationship i.e. for each database table there should be an entity bean?I don't think this should be the case, but if it is, then isn't there a case that we may end up ...

I like to think of myself as a purist when designing OO relationships. Specifically, I don't agree with having classes in one package (com.foo) reference classes in a 'sub' package (com.foo.bar). I also don't agree with a class instantiating subclasses of itself. The way I see it is that ...

Hi,I have a java application with a gui. My teachers learned that the logic classes shouldn't receive any gui classes in parameter..but i would like to write messages (informing on what's happens in my program)into a panel of my application. But i can't see how to do that without to give my ...

I am new to j2ee and as per the j2ee tutorials 1. I have installed j2ee sdk, 2. installed jdk 1.3.1 3. installed ant 4. set JAVA_HOME 5. set J2EE_HOME 6. set ANT_HOME, but when I try to start the j2ee server on my command prompt, I am geting follwoing error, what am I missing ? Please ...

Hi.First, sorry for my bad english :)When I design a catalog and item (of any type) ... should I use a Collection for the catalog. Usually, I need only a few data, and it could be a really large Collection (from a DB), and I want to list a couple of properties (and give some ...

ok, here's the point.We work with the problem domain and develop the analysis model. The analyst at this stage doesn't concern himself with the implementation details, some low-level code patterns and the programming language (well, let's forget for now about C's multiple inheritance and ...

Hi my web component need to read some values from a property file.It works with Tomcat.However when I run it on J2EE I get following error.Any help is appreciatedRegardsjava.security.AccessControlException: access denied (java.util.PropertyPermission * read,write)at ...

I'm thinking of using DOM as my value objects. There are however serious serialization problems with this approach. This can be coped with by using JDOM, but I'm not that willing to step away from JAXP, and polluting my code with org.jdom.Document instead of org.w3c.dom.Document.Any thoughts ...

I would like to know how to connect web container(Tomcat 4.1) to JBoss application server 3.0.4?

Hi,How do you deal with the Local and RemoteHome (EJB) Object within a BusinessDelegate and consequently in the ServiceLocatorPattern? I have 2 different methods (getLocalHome / getRemoteHome) for retrieving the EJBLocalHome and EJBHome in the ServiceLocatorPattern but i'm not sure how to ...

Is it possible to connect to EJB container running on JBOSS from simple java application (without the web server). Similar like we could use for example BAS 4.5.1 application server. For that server only thing that has to be configured is osagent port: -Dvbroker.agent.port=XXXXX (port on which ...

Hello,I have two classes: A and B. I am trying to establish the difference between:1. UML composition (an arrow pointing from Class A to Class B with a small open diamond at the opposite end from the arrow head) 2. and another relation which name I don't know that is represented by the very ...

Hi,Does anyone have a suggestion for a free tool that allows for the creation of UML diagrams and then converting it to Java code?

Hello.I've used the MVC Pattern through all my project. But now, I'm developing dozens of GUI responsibles for show reports to the user. So, where to put the SQL querys (some complex ones)? Should I put everything into controller?Is there another pattern that makes it ...

Hi there,I'm pretty new to J2EE, so please excuse my inexperience.I was wondering what is the best way of repeating a certain task (e.g. calling a session bean that does something for you) *within* the J2EE environment. I know that J2EE doesn't really support multithreading - but what about a ...

Hi,My XML file needs to access the following DTD file.<!DOCTYPE ejb-jar PUBLIC '-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 1.1//EN' ' http://java.sun.com/j2ee/dtds/ejb-jar_1_1.dtd'>It has problems going through my Internet proxy, which requires username and password. Does ...

Hello,I came across two UML notations. I would like to know the difference between them.I have one class A and an interface B-1st notation (dotted line: Name of relation?)|A| - - - - - -> |B|-2nd notation (full line: Association)|A| --> |B|I know the second relation is an association that ...

I want to use a data buffer in a Browser(for example:Internet Explorer),when a http connection is disconnected I can operate on the data buffered(Perhaps in XML format),for example,I can query,sort or modify the data buffered,afterthat I can update the data source truly,just like in a C/S model ...

Hello,Suppose I have two classes A and B with the following class diagram:|A|- - - - - ->|B|According to what I understand, it means that B is either a local variable of A or a parameter of one of A's methods. Can B be an instance variable of A or would it change the relation to ...

I run a windows box, and I downloaded argouml and poseidon and I was very annoyed that the save feature failed a good portion of the time (one of those required features) but otherwise I liked it. Are there any other good free progs that are like argouml but get basic save features right?

Hello,I am designing an application where there are Employee objects and there are WorkBlock objects. A WorkBlock object is simply a block of time that the Employee is scheduled to work.Each Employee can be scheduled to work one or more WorkBlocks. Each WorkBlock, of course, has one Employee ...

Let's assume that we have a huge project developing a J2EE app. We make lots of use of EJBLocalObjects well aware that the servlets and EJB's will execute in the same JVM. At some point in time, we decide to deploy our app in a cluster that supports HTTP session failover.The fact that ...

This is a very general question about mulitple inheritance.I now how it's done (or perhaps not done) in Java, but I'd like to know how it's done in general.I can understand an amphibious vehicle inheriting the ability to drive from Car and the ability to navigate from Boat, but how does one ...

plz, check the diagram at http://www.mycgiserver.com/~dronskithis is considered to be more a high-level diagram, than a design one. does such model communicate the idea? i'd like to here from you concerning exactly how clear the model is. after your reply i'll describe what i really wanted to ...

Hello,I'm looking for a tool (open source if possible) which describe an existing relationnal database automatically in UML.Any ideas?Thank youSylvain

Hi all friends,I am a beginner of J2ee technology.But I could not find the exact answer of "Why Ejb?"(what are the advantages of using EJB). Can any one plz tell me the answer of that or give me some links, so that I can find the exact answer.RegardsBikash

Hello!I would like to create interface to my J2EE application for XML. Application client could be wroten in any language so I should use XML. Any good point to start?

Hello all,I'm in first OO complex project and I've a few question regarding how to map SQL tables into Business Objects (and viceversa).The project is a complex web site so I access Business Object from JSP.The difference I noticed with JSP vs other apps is that all thing is stateless, ie., ...

Hi , I read the Version Number Pattern in EJB Design Patterns. What happens in a System where large no.of clients are interacting and doing millions of transactions where in they will be updating data .since in between the updates the version number will change and they will get the message ...

Hii am trying to develop an ecommerce engine. was just wondering if its possible to make it server independent i-e can also plug into ASP/IIS Server, Cold fusion etc.

Hellou people,I've come across several implementation of Page-by-Page Iterators. OK, the one mentioned in J2EE Core patterns does solve some problems, but I think the best implementation not only iterate in memory but on the DB access level.Most real project implementation that I see retrieves ...

What is diff bet. facade and adapter pattern?

Why ejbPostCreate() is used in entity bean? why it is not there in session bean?

What is the diff bet. LDAP & Data base?How LDAP stores data?

Hi,I've implemented the front controller pattern using a Servlet and some JSP pages. The issue I have is that if the JSP page button is clicked, the controller handles the request and performs the proper forwarding.But for instance, if I type in the URL for the page directly without going ...

Hi,from the UML Spec about Sequence diagrams:Variation: IterationA connected set of arrows may be enclosed and marked as an iteration.But it does not specify [em]what[/em] is meant by a 'connected set' and[em]how[/em] to mark it as an iteration.At least I can't find it.Does anybody know how ...

Hi,I have few clarifications.Say if we have a object of class2 instance that is created in method1 of class1 then should we represent the class diagram with class1 and class2 as two classes with a relation from class1 to class2 with direction pointing to class2 or since the instance of class2 ...

Hi Ppl,What is the best way to insert this chart(it's data) in database.NAPIER 8TE AUTE 105NORSEWOOD15105DANNEVIRKE1815105WOODVILLE201815105PALMERSTON NORTH This chart represents a fare from one city to another. I need to store these fares in a database. What I have done now is created 3 ...

Hi guys,I am in a very interesting situation at work. I am in a short break between projects and am attempting to put together a company "software development process" that we can adhere to in future.However, I am struggling in getting this thing started and need some help.I'll give you some ...