public class FerretBox {Centroid centr = null;public FerretBox(Centroid ctr) {if(ctr == null)centr = new Centroid();else centr = ctr;centr.Bind_FerretBox(this);}}public class Centroid {FerretBox fb = null;public Centroid() {}public void Bind_FerretBox(FerretBox fb) {this.fb = fb;}}I have a main ...

Hi,I have coding in Java for over a year now, and I am curious what is a good way to learn good OOD practices? I particularly learn best from example, but any references would be helpful.Thanks!

I'm currently writting a system (let's call its the "Engine") into wich it is possible to "plug" external behaviors.To do so, I provide a set of interfaces and classes that are to be used for the development of the "plug-ins".Once the Engine is deployed, it is possible to add newly developed ...

My application is a J2EE application?and we are using delegates to call the Business objects which in turn call the DAO抯. (Struts framework)This is the pattern for business calls.Now my question is? If we have some common utility classes?then is there any pattern for using those classes ...

I was wondering if it was possible to implement the factory pattern using a generic like sintax with java5. Something like:IFactory factory = new ConcreteFactory();Car c=factory.CreateObject<Car>();I saw this article the other day ...

Are these 2 mutually exclusive? OR can they be overlapping in respect with time line. By that I mean "Is there a case where we have a compostion at the beginning of time BUT then as we evolve with time it becomes an aggregation?" OR vice-versa?

Hi,I have one array list having more than 100 objects in it.I have two way to ietrator.1.for(int i=0; i<list.size(); i++){Object o = list.get(i);}2.Iterator i = list.getIterator()while(i.hasNext()){Object o ...}which is better in performance ...

Hi guys :)I'm not quit sure if this is the right forum to post this question...can any one describe me what is the difference between an Application which is inherently concurrent and one which is potentially concurrent?and why is a real -time system is inherently concurrent?any ideas are ...

hiI'm writing a project whose ultimate goal is loading into a DB (using hibernate) a tree of objects based on a flat file messagethe loader should also validate the message while parsing it, so that nothing gets created if some validation error occursthese messages are structured into fixed ...

Anyone care to comment on the following which claims that Factory, Interpreter, Bridge and Flyweight are no longer patterns?And Singleton was almost voted out. http://martinfowler.com/bliki/OOPSLA2004.html

Let's say I have an abstract class and 4 subclasses extending it.Somewhere in my program I keep an ArrayList of many objects of these subclasses.May I use then a factory for creating those subclasses ?Cause isn't the purpose of a factory not to only call it ones in you program and ,based on ...

Hi Can anyone tell me where i can find examples of how to model javabeans (not EJB) in UML?Are there any particular methods of uml design that i should use such as "activity diagrams" for the system, or just "class diagrams" for the actual code?I'm especially looking for design examples of a ...

HiI've been thinking about ways to provide authentication and access privileges to my Facade classes. I would like to put all the authentication and access privileges logic inside the Facade so I can publish the Facade as a Web Service or a Session Bean. After thinking a lot about it I found ...

Hi ,guys .I'd like to learn something about refactor,could you recommend me something to study.Any advice is highly appreciated!Mars

Dear all,I'm on a new project that is still in the Design phase. The project has to be designed in layers: presentation, business and persistence.After completing previous design steps, I was asked to make a Domain Model in UML, and now it's finished, and all the business rules are ...

Hi,I have query regarding the locking of the table by number of DAO instances created in the method level...is that true?...In method level as per the database call needed, i am creating the instance of DAO and then calling the update method of DAO object.i.epublic class Abc{public Abc(){} ...

Hi,I have query regarding the table locking ..... Is that true- that the table will be locked if "n" number of DAO instances created in the method level... ?... In method level as per the database call needed, i am creating the instance of DAO and then calling the update method of DAO ...

I have an interface and a set of ComparatorS which are only used for objects which implement the interface. So I put the ComparatorS in the interface like so (not actual code because it is for my job):public interface Abc { //Class loader should only do this once so they are basically singleton ...

Hello forum,i have a question about "how object oriented design lends itself to the concepts of design by contract and how require and ensure clauses can be simulated in languages which do not have them"thanks for your help!David

Hello,I have a question regarding DAO抯.DAO抯 help solve the problem of switching you data access layer, that I know. I wonder however how reusable they are. An example:UserProfileDAO declares the method findUserProfile(int userId) and returns a UserProfile instance. In the next project I need ...

Hello,Can anyone tell me what the difference is between 3 tier and n tier please?What do the 1, 2, 3 and n tiers correspond to?Thanks in advance,Julien Martin.

When I was in college someone asked me why transistors amplify. Although I could give mathematical explanations, I could not give an answer that made sense on a gut level. Later I put together a cogent explanation: The transistor modulates the power that is provided by a power supply.How would ...

Hello,I am currently working on UML and I am trying to understand better what a dependency is and most importantly how it translate into java. From what I understand a dependency means that if class A depends from class B, B is present in one of A's methods. I am right? Are there other ...

I've got a List of different classes which implement a DisplayableObject interface. There's a set of gui checkboxes which controls which specific typesshould be displayed. I loop through my list in paintComponent() todraw to the screen.What's the smart way to tie this together?Right now, the ...

Im writing one of my first large gui projects, and Im trying to follow good OOP techniques,but was never taught how to do this in Java (no callbacks).I have a subclass of JPanel that has:1 text area2 Jbuttons2 radio buttons (1 button group)The JPanel loads a vector of questions and displays one ...

Hi,We are designing a system which gets data from front end(JSP), in this data, only few of the input fields are to be updated in one system, which is a thrid party system, and the rest of the fields not requried by the third party application should be kept in our application database.The ...

Hi, I need to design a page, which has the functionality to add and remove documents and later submit it..My doubts are1. when he adds a document - whether i should it in the database at that itself or no.?2. If no, how to keep track of all teh documents he has added.3. Whether I should save ...

have you ever used an extreme design patterns that is not in literature?

Hi,I was curious what everyone's opinion (or at least those who frequent this forum) was about a website explaining Design Patterns using Java.I was thinking about making a site which discusses various design patterns, including real-world analogies (to try and make things simple and clear), ...

Hello Everybody, Iam doing my Masters in Computer Science. I want to do a project in Java & in particular on Patterns on Linux(optional) platform as part of our course.The team size is 2 and the available time duration is 2 1/2 - 3 months. Please suggest some projects. Thank ...

Just a question out of curiosity. So if and only possible, can you let your valuable experience and/or observation speaks. 1M Thanks.Quickly and scope-wise OO Design Principles mentioned/interested are:SRP - Single Responsiblity PrincipleOCP - Open Closed PrincipleLSP - Liskov Substitution ...

While going over JUnit documentation, I saw this Collecting Parameter Pattern.I try to understand it but wonder it was named Collecting Parameter instead of Collecting b]Data Parameter. or ... http://c2.com/cgi/wiki?CollectingParameterBy the way, is this a valid real life example of Collecting ...

Hi All,I am currently working on a new project and I just wanted to make use of DAOs and Singletons.I just wanted to make sure that what I am doing correct and that it would not cause any problems in the future.Here is what I am doing..1. I moved all my data base interactions into just one ...

Hi All,Just wonder if anyone if you guys can give me some ideas no implementation of paging. How would normally paging be done? To be more exact, my question is referring that the paging should be done :1. SQL Level Here the retrieval of records are queried into block of record. ie: within ...

I just started my job and me and 2 others are going to be working with struts. I just arrived here and dont know anything about this, I dont even know java yet. My supervisor wants me to learn how struts works, how the system works, and I have no idea. I am honestly starting from nothing here ...

Hi all!I have a problem when I try to store a class A into a B object.public class A{int i;A(){ }protected doAction(){ //whatever }}public class B extends A{B(){super();} protected doAction() { //whatever}}public class C{C(){}public A getResult(){ A a = new A();return a; }}Can anybody explain ...

Hi All,In real time where will we use this Singleton Class..Could you give me an Exampel...AMJ

I have a number of POJOs that I want to display in a tree view and a graphical view. This means I need to introduce two new interfaces to provide the necessary functionality. e.gpublic interface ITreeNode {Object[] getChildren(Object parent);boolean hasChildren(Object parent);String ...

Hi.I'm creating a project that uses the MVC design pattern, and being eager to make sure I follow the best practices I have a couple of questions. When notifying a 'View' of changes to the 'Model' is it preferable to effect this notfication using the Observer/Observable pattern, or through ...

I am a new to uml and trying to get my head around them. Just wondering if anyone can help me out with a problem. I have been working on this but always end up wrong. I have some code from junit below:I have to a. Draw uml class diagram with all associations, relationships etcb. Draw uml design ...

Hello All,Would you like to help us build this? http://skribe.noumenaut.com:8080We need your help!We've been working hard on a high-end blogging application that will soon go live. The link above is a very early integration build.We抮e seeking several people to fill a few different roles, ...

Hello,I need to parse a very complex text file. If I keep all the parsing code in one file, it will be huge. Then I thought probably I can use strategy patthern to decouple it. "Another technique has a context pass itself as an argument, and the strategy request data from the context ...

Hello,I am currently working on UML and I would like to know how powertypes are implemented in java. Can anyone please post some java snippets or throw some light on the subject?Thanks in advance,Julien Martin.

What is the basic difference betweent the two architectures and which one is preferable ?

Hi,Is java.util.Runtime a Singleton class ?-Shishir

Hello,(disclaimer : if you agree that this topic does not really belong to this forum please vote for a new Development Process forum there: http://forum.java.sun.com/thread.jspa?forumID=53&threadID=504658 ;-)My current organization has a dedicated QA team.They ensure end-user functional ...

Hello,I am debating using the Command pattern as my primary strategy for implementing my J2EE enterprise app business logic and would like some advice. The general idea is to have only a few types of abstract commands (such as a ReadComand, an UpdateCommand -- I might have a slightly finer ...

I'm having a problem compiling an Action class using Net Beans.My code for the execute function is as follows:public ActionForward execute(ActionMapping mapping,ActionForm form,HttpServletRequest request,HttpServletResponse response)throws IOException, ServletException { String username = ...

I was having a conversation the other day with a software developer, and he asked 'What is MVC?" I told him and he said he will never need to know that pattern because he works on TCP networking and messaging formats.So is there a good reason for someone who never works with GUI's to learn ...

I am creating a service to insert a row in table. Before inserting, the data need to be validated. So how the service should communicate all the missing data back to the 搑equestor of the service.?br>Thanks in advance