I'd like to have a GWT app with a UI that is configuration-driven, meaning that if I make certain database changes, or deploy a different XML descriptor (outside the WAR), then I can change the look, feel and behavior of the UI without deploying any code changes. My reasons for wanting this lay outside the context of this question and I would need to provide way-too-big of an irrelevant backstory to justify placing it all in this question.
For instance, say with one particular configuration, the UI (a place in GWT verbiage, or page/screen) might just consist of a simple button in the center of the screen. Then, I make some database changes, and now, the same place renders with 4 buttons in each corner of the screen, and a "Hello, GWT" label in the center. Same code, but different DB values (or XML) cause the UI to look/feel/behave differently.
I'm trying to figure out how to design such a system, but am struggling and not sure if it's even possible. If it is possible, I'd appreciate a good explanation on how it might work, and maybe even some pseudo-code to get the creative juices flowing.
If it's not possible, then I'd like a concrete (definitive) answer as to why. As I've found on StackOverflow so many times now, when someone says "this is impossible!" it's usually just an advanced topic that is beyond their level of understanding :-), and what I'm asking isn't impossible, it's just hard! Thanks in advance!
Yes, this is definetely possible. I've went once through that.
But it's not a standard way of doing, so don't expect to find much in internet. You must invent the solution yourself.
Simply, you must create a channel/service/JSON service from which the GWT application will read your configuration, and build the UI according to it. You can invent your own description language, or use some existing format, for example XUL, to describe the UI. It's however a hard way, but giving a lot of satisfaction once you accomplish it.
Related
I am new in 3D modelling, I am not expecting exact ans but any hint, link or direction will good for me. I am working in java and i have to work with 3D model now. So its like, I will make a model (using XYZ software) and define some parts of it lets say part1, part2. Then at run time on browser user have a drop down to select the part and then he give some value , now i want to change the 3d model according to that value of that part (that could be length,width etc) and user should be able to see that on browser.
First, Is it possible, changing dimension at runtime (I can make some restriction also)?
Second , Any hint , library or logic direction will be great help.
I can go for any language , any software now as because I am about to start from scratch.
If I haven't made my question clear, do let me know.
One solution I can think of is for different possibilities ,I should have different model already in background, and load that one , whose dimensions matches with user selection.
OR any other suggestions ??
Your question is quite unclear in that you say that you are using Java but can go for any language...
I am making the assumption here that you are indeed using Java. There are several libraries available for Java that support "rendering" of 3d objects. The level of abstraction depends on the individual library/framework.
Some example of what are referred to as low-level libraries:
Java 3D, (OpenGL wrappers)lwjgl, JOGL.
Some higher level frameworks:
JMonkeyEngine, Andor3D, Ogre4J.
I only list a few as an exhaustive list is not what SO is for, nor am I going to compare them for the same reason.
If you want to code the loading of assets, how they render, how they are stored at runtime, how they should be rendered then you will probably be going with the lower level ones. Going with a framework means you care less about what low level graphics library you use rather what the framework can offer.
Your second set of questions really deal with details that you would only need to worry about after the initial choice. If you have model loading code then you can just load a new model triggered by an event.
Edit: Only caught that you said run in browser, if that is a requirement then that complicates things. You would probably need to go another route, perhaps WebGL and javascript, or three.js.
Again without a more specific question, can't really give a more concrete answer.
Edit : Reuest per comment:
Although flash support is being phased out of web-browsers there are several libraries available. papervision, unity3d-web, away 3d. I have away3d myself on a small project for a simulation visualisation project. It was pretty easy to use, but for what I needed perfomance was not good, but then again I would not recommend using flash for 3d either. That said it has probably improved since then.
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I have an application written in Java. In is stored in several files. It uses different classes with different methods. The code is big and complicated. I think it would be easier to understand the code if I have a graphical model of the code (some kind of directed graph). Are there some standard methods for visualization of code. I am thinking about usage of UML (not sure it is a correct choice). Can anybody recommend me something?
ADDED:
I consider two possibilities:
Creating the graph by hands (explicitly).
Creating graph in an automatic way. For example to use some tools that read the available code and generate some graph describing the structure of the code.
ADDED 2:
It would be nice to have something for free.
I tried using a number of UML tools and found that the reverse-engineering capabilities in most UML tools were not helpful for understanding code. They focus on designing needs and reverse-engineering capabilities often just ends up showing huge pictures of lots of useless information. When I was working on the Microsoft Office codebase, I found using a pen-and-paper more helpful that the typical design/modelling tools.
You typically want to think about doing this in a number of ways:
Use your brain: Someone else mentioned it - there is no substitute to actually trying to understand a code base. You might need to take notes down and refer back to it later. Can tools help? Definitely. But don't expect them to do most of the work for you.
Find documentation and talk to co-workers: There is no better way than having some source describe the main concepts in a codebase. If you can find someone to help you, take a pen and paper, go to him and take lots of notes. How much to bug the other person? In the beginning - as much as is practical for your work, but no amount is too little.
Think about tools: If you are new to a part of a project - you are going to be spending a significant amount of time understanding the code, so see how much help you can get automatically. There are good tools and bad tools. Try to figure out which tools have capabilities that might be helpful for you first. As I mentioned above, the average UML tool focuses more on modeling and does not seem to not be the right fit for you.
Time vs Cost: Sure, free is great. But if a free tool is not being used by many people - it might be that the tool does not work. There are many tools that were create just as an exploration of what could be done, but are not really helpful and therefore just made available for free in hopes that someone else will adopt it. Another way to think about it, decide how much your time is worth - it might make sense to spend a day or two to get a tool to work for you.
Once there, keep these in mind when going trying to understand the project:
The Mile High View: A layered architectural diagram can be really helpful to know how the main concepts in a project are related to one another. Tools like Lattix and Architexa can be really helpful here.
The Core: Try to figure out how the code works with regards to the main concepts. Class diagrams are exceptionally useful here. Pen-and-paper works often enough here, but tools can not only speed up the process but also help you save and share such diagrams. I think AgileJ and Architexa are your best bets here, but your average UML tool can often be good enough.
Key Use Cases: I would suggest tracing atleast one key use case for your app. You likely can get the most important use cases from anyone on your team, and stepping through it will be really helpful. Most IDE's are really helpful here. If you try drawing them, then sequence diagrams arethe most appropriate. For tools here I think MaintainJ, JDeveloper and Architexa are your best bets here.
Note: I am the founder of Architexa - we build tools to help you understand and document Java code, but I have tried to be unbiased above. My intention is to suggest tools and options given that this is what I focused on as part of my PhD.
The most important tool you should use is your brain, and it's free.
There's no reason why you have to use any sort of standard method of visualization, and you can use whatever media you like. Paper, whiteboard, photoshop, visio, powerpoint, notepad: all of these can be effective. Draw a diagram of classes, objects, methods, properties, variables - whatever you think is useful to see in order to understand the application. The audience is not only other members of your team, but also yourself. Create diagrams that are useful for you to look at and quickly understand. Post them around your workspace and look at them regularly to remind yourself of the overall system architecture as you build it.
UML and other code documentation standards are good guidelines for the types of diagrams you can do and the information you should consider including. However, it is overkill for most applications and basically exists for people who can't take personal responsibility for documenting without standards. If you follow UML to the letter, you'll end up spending way too much time on your documentation instead of creating your application.
It is stored in several files. It uses different classes with different methods. The code is big and complicated.
All Java code written outside the school is like that, particularly for a new developer starting on a project.
This is an old question, but as this is coming up in Google searches, I am adding my response here so that it could be useful to the future visitors. Let me also disclose that I am the author of MaintainJ.
Don't try to understand the whole application
Let me ask you this - why do you want to understand the code? Most probably you are fixing a bug or enhancing a feature of the application. The first thing you should not try to do is to understand the whole application. Trying to understand the entire architecture while starting afresh on a project will just overwhelm you.
Believe me when I say this - developers with 10+ years of solid coding experience may not understand how certain parts of the application work even after working on the same project for more than a year (assuming they are not the original developers). They may not understand how the authentication works or how the transaction management works in the application. I am talking about typical enterprise applications with 1000 to 2000 classes and using different frameworks.
Two important skills required to maintain large applications
Then how do they survive and are paid big bucks? Experienced developers usually understand what they are doing; meaning, if they are to fix a bug, they will find the location of the bug, then fix it and make sure that it does not break the rest of the app. If they need to enhance a feature or add a new feature, most of the time, they just have to imitate an existing feature that does a similar thing.
There are two important skills that help them to do this.
They are able to analyze the impact of the change(s) they do while fixing a bug. First they locate the problem, change the code and test it to make sure that it works. Then, because they know the Java language well and the frameworks 'well enough', they can tell if it will break any other parts of the app. If not, they are done.
I said that they simply need to imitate to enhance the application. To imitate effectively, one needs to know Java well and understand the frameworks 'well enough'. For example, when they are adding a new Struts Action class and adding to the configuration xml, they will first find a similar feature, try to follow the flow of that feature and understand how it works. They may have to tweak a bit of the configuration (like the 'form' data being in 'request' than in 'session' scope). But if they know the frameworks 'well enough', they can easily do this.
The bottom line is, you don't need to understand what all the 2000 classes are doing to fix a bug or enhance the app. Just understand what's needed.
Focus on delivering immediate value
So am I discouraging you from understanding the architecture? No, not at all. All I am asking you is to deliver. Once you start on a project and once you have set up the development environment on your PC, you should not take more than a week to deliver something, however small it may be. If you are an experienced programmer and don't deliver anything after 2 weeks, how can a manager know if you really working or reading sports news?
So, to make life easier for everyone, deliver something. Don't go with the attitude that you need to understand the whole application to deliver something valuable. It's completely false. Adding a small and localized Javascript validation may be very valuable to the business and when you deliver it, the manager feels relieved that he has got some value for his money. Moreover, it gives you the time to read the sports news.
As time passes by and after you deliver 5 small fixes, you would start to slowly understand the architecture. Do not underestimate the time needed to understand each aspect of the app. Give 3-4 days to understand the authentication. May be 2-3 days to understand the transaction management. It really depends on the application and your prior experience on similar applications, but I am just giving the ballpark estimates. Steal the time in between fixing the defects. Do not ask for that time.
When you understand something, write notes or draw the class/sequence/data model diagram.
Diagrams
Haaa...it took me so long to mention diagrams :). I started with the disclosure that I am the author of MaintainJ, the tool that generates runtime sequence diagrams. Let me tell you how it can help you.
The big part of maintenance is to locate the source of a problem or to understand how a feature works.
MaintainJ generated sequence diagrams show the call flow and data flow for a single use case. So, in a simple sequence diagram, you can see which methods are called for a use case. So, if you are fixing a bug, the bug is most probably in one of those methods. Just fix it, ensure that it does not break anything else and get out.
If you need to enhance a feature, understand the call flow of that feature using the sequence diagram and then enhance it. The enhancement may be like adding an extra field or adding a new validation, etc. Usually, adding new code is less risky.
If you need to add a new feature, find some other feature similar to what you need to develop, understand the call flow of that feature using MaintainJ and then imitate it.
Sounds simple? It is actually simple, but there will be cases where you will be doing larger enhancements like building an entirely new feature or something that affects the fundamental design of the application. By the time you are attempting something like that, you should be familiar with the application and understand the architecture of the app reasonably well.
Two caveats to my argument above
I mentioned that adding code is less risky than changing existing code. Because you want to avoid changing, you may be tempted to simply copy an existing method and add to it rather than changing the existing code. Resist this temptation. All applications have certain structure or 'uniformity'. Do not ruin it by bad practices like code duplication. You should know when you are deviating from the 'uniformity'. Ask a senior developer on the project to review the changes. If you must do something that does not follow the conventions, at least make sure that it's local to a small class (a private method in a 200 line class would not ruin the application's esthetics).
If you follow the approach outlined above, though you can survive for years in the industry, you run the risk of not understanding the application architectures, which is not good in the long run. This can be avoided by working on bigger changes or by just less Facebook time. Spend time to understand the architecture when you are a little free and document it for other developers.
Conclusion
Focus on immediate value and use the tools that deliver that, but don't be lazy. Tools and diagrams help, but you can do without them too. You can follow my advice by just taking some time of a senior developer on the project.
Some plugins I know for Eclipse:
Architexa
http://www.architexa.com/
nWire
http://www.nwiresoftware.com/
If you want to reverse engineer the code, you should try Enterprise Architect
have you tried Google CodePro Analytix ?
it can for example display dependencies and is free (screenshot from cod.google.com):
Here is a non UML Tool which has very nice visualization features.
You can mapping the lines of code per class / method to colors / side lenght of rectangles.
You can also show the dependencies between the classes.
http://www.moosetechnology.org/
The nice thing is, you can use Smalltalk scripting for displaying what you need:
http://www.moosetechnology.org/docs/faq/JavaModelManipulation
Here you can see how such a visualization looks like:
http://www.moosetechnology.org/tools/moosejee/casestudy
JUDE Community UML used to be able to import Java, but it is no longer the case. It is a good, free tool.
If your app is really complex I think that diagrams won't carry you very far. When diagrams become very complex they become hard to read and lose their power. Some well chosen diagrams, even if generated by hand, might be enough.
You don't need every method, parameter, and return value spelled out. Usually it's just the relationships and interactions between objects or packages that you need.
Here is a another tool that could do the trick:
http://xplrarc.massey.ac.nz/
You can use JArchitect tool, a pretty complete tool to visualize your code structure using the dependency graph, and browse you source code like a database using CQlinq.
JArchitect is free for open source contributors
Some great tools I use -
StarUML (allows code to diagram conversion)
MS Visio
XMind (very very useful for overview of the system)
Pen and Paper!
This seems to be a popular complaint on many programmer forums so I wouldn't be surprised if this question was already on here. Sorry if it has already been answered but I've searched and couldn't find one that relates to Java/OO.
I have a somewhat complicated application that was written a number of months ago. It works well, but is slow and the code is extremely ugly. Classes are split up for no logical reason, half the UI is in the logic code and it's really frustratingly built. I want to redesign and redevelop this program to the correct design standards, yet I don't want to break it completely. There's no design documents, no documentation, nothing but the code (with no formatting) and the built application.
What's the best way of taking an existing Java project, written in the most annoying way possible and redeveloping it in the best way possible? Are there any good tools that'll help me find speed bottlenecks or for extensive testing in NetBeans? Any help for a total novice of testing would be greatly appreciated.
EDIT: You're correct when saying that we don't really understand this program. It does what we want, but it also does other things and we're not exactly aware of, like creating strange graphics and weird numbers appearing on the UI. The main reason we want this redesigned is so that we can actually find out what's going on, but as I've said the code is so messy you'd think it was written by a genius that didn't want us to find out his secrets.
"with no formatting"
Netbeans has an automatic formatter option in the "Source" menu. That would be a good start.
"There's no design documents, no documentation, nothing but the code"
As you work out what parts do, it will serve you well (and your successors) to document this. That way you will start having documentation you can refer to.
Using JUnit to start adding some Unit Tests to sections before you refactor them wouldn't hurt either.
"I want to redesign and redevelop this program to the correct design standards, yet I don't want to break it completely."
Start small. Work out some simple things that could be designed better and concentrate on them first. Using the Refactor ability in Netbeans will help greatly with this. Concentrate on making sure everything that you refactor still works the same (which is why starting out small helps). The more of the small stuff that you clean up, the easier the bigger stuff will be when you come to it.
Also, make sure what you are refactoring is actually an improvement...
I would echo C. Ross's comments and add these strategies for common "bad code" scenarios I've dealt with in the past:
Code Duplication: The only thing worse than bad code is multiple copies of the same bad code. Get familiar with the entire code base by speed reading it (get it's flavour) and identify instances of cutting-and-pasting code. Refactor those to a single implementation and remove the duplication. That may be it - or you can continue to refine the single copy of that code.
Don't be in a hurry to fix it: Only clean up code that you actively need to maintain and/or understand. This is a variation of if it ain't broke don't fix it I like to call if you don't need to change it don't fix it. But, anytime you need to touch a piece of code take 10 extra minutes to clean it up. Maybe that's just adding formatting it, adding some inline comments, renaming variables to make sense, etc. Any code you need to update will most likely be revisted again in the future, and now you've made it all clean. Code you haven't had to actually change yet can remain ugly without harming anything.
Good luck :)
As already mentioned, an ugly code can be cleaned up by a monkey with a proper IDE so I wouldn't go to your manager with that argument alone.
Being pragmatic, I would go with:
grab some tools (a profiler, code duplication tools) to find a couple of pain points
for each point, come up with a battle plan how to solve it (with short specification, design, maybe code sample, test cases...).
go to your manager and let him decide which one to tackle first
The danger is to do too much and to try to clean everything. Depending on the size of the application, it may take years to clean it up (because you won't do this full time) so just be patient.
And of course, when you revisit part of the code, just clean it up with your favorite IDE.
Really the only answer is sweat equity, but some things that can help:
A good IDE with refactoring tools, such as Eclipse
Profiling tools for optimization
Code coverage tools, such as EclEmma
Javadoc, sometimes it helps to get a high level view of even bad code
Happy refactoring!
What you have is essentially a prototype. Tell your manager that that is what it is, and that it should be rewritten to reach production quality.
JProfiler is excellent, I was using it just yesterday in fact to find a performance bottleneck in some Java code I had.
If you can get some automated tests in place you'll be in a better position to start refactorring as you can then assetr that it's still functioning as expected. Specifically you should focus I think on very high level tests of the system, if it's a web app take a look at selenium and/or other web app testing frameworks.
Apart from that, be ready to head down a lot of dead ends, try and avoid taking too much change on at once if possible. The more you can break down the largre app into smaller chunks which you can take on one at a time the more succesful you're likely to be. Also, be prepared to accept that some of it may well remain crappy forever, if it ain't broke as they say, don't fix it.
I have to make some animated design with lots of pretty effects and color gradients in a SWT compliant way ...
I assume what I try to mean is not clear as water so I'll try to explain more...
I have an RCP application in which I need to have a special page whose content is fed by a class that sends it either beans or strings (or postcards or whatever, it can have to get almost anything) and has to make a nice presentation of all that it gets by building artistical representation of it and animating the whole.
The artistic transformation here is not the problem (I'll handle it and let all freedom to my artistic sick mind) but the problem is to find any framework or plugin that is able to build pretty animations and all the stuff in a SWT shell...
You can use Timing Framework or Trident. Both of them based on the notion of changing bean property values, which would work for SWT or Swing.
You'd have to read about them to see which one you like more. For simple effects Trident looks easier, but it should be your personal choice.
I'm not sure whether this could help or not
http://www.eclipse.org/nebula/widgets/stw/stw.php
I'm starting a fairly complex Swing application that heavily graphics-oriented with about 1000 separate jpegs, 30+ different forms, and timers keeping track of the rate of user-interactions throughout.
My question is from a practical programming perspective, after I've already written a storyboard for the entire project and got it approved by the client, where's the best place (code-wise) to begin programming this massive project and in what order should I program the elements?
(Example Answer: first begin coding the declare and init statements of all the necessary pieces, then write skeleton versions of all the methods, then deal with swing design and layout manager (gridbag), and then deal with Events and Listeners)
Thanks for the advice everyone, oh and btw I really love StackOverflow!
You're describing a "waterfall" development approach - completing some level of the program first, then completing the next level etc. It's indeed one possible approach, but many people find it so called tracer bullet approach better; first make something functional, then learn from it, adjust what's needed and proceed. It's especially useful if you're working with a client, because by showing prototypes you can get feedback and avoid misunderstandings.
I'd pick up a book on TDD and even if you're not going to write automated tests, it will be full of good advice on how to approach your project.
After that I'd pick a single piece of functionality that slices all the way through your application vertically and implement that end-to-end. This should allow you to get any infrastructure/frameworks in place and spot any gotcha's that may get thrown up out of your design.
If your client has the time free, show them each piece of functionality along the way and make sure that every piece you do adds some value to the product.
--EDIT
In addition I'd take a look at using a graphical designer for your screens instead of using the GridBagLayout. That will just waste time and can quickly become a maintainence nightmare when changing screens. I personally prefer the ones that work in a resource file type way, where the screen is essentially "compiled" and you just load it into your code
I prefer writing the UI so, that first I write (using TDD) the backend classes which implement the behaviour of the UI, without any dependencies to the presentation of the UI (i.e. without Swing or any other UI library). After that I write a thin presentation layer with an UI library, where all the event handlers etc. delegate to the UI backend (they should be just one-liners without any logic). The benefit of this is that you can easily write tests for the UI, which in turn makes it easier to change and maintain the UI. See the links at http://martinfowler.com/eaaDev/ModelViewPresenter.html for more details.
At a higher level, first implement the features which will produce the most value to the users. Try to get something to show as early as possible, so that you can get feedback from the users and improve any deficiencies in the UI. You can fake most of the background services (for example the database and business rules), so that the UI can be used, even though it does not yet really do anything.
I think mad-j has the words of wisdom.
Don't concentrate on the 'all'... identify sections/components/modules and deliver those. Then move on to the next and the next. This is called Iterative and Incremental Development (a response to the weaknesses of the waterfall model)!
This will also allow you to create tools and frameworks which should make your development easier and faster as you move along.
This will allow you to show your clients functional parts early. But a word of advice! Your client will more than likely keep changing its requirements, changing the GUI, changing its mind, etc. I've seen entire projects fail due to these continuous changes. It is out of the scope of this question to mention any more on this, but please be aware that it more than likely will happen and be prepared to deal with it!
If you and the client have functional parts, they can be tested immediately rather than testing one huge system.
By completing functional parts iteratively will probably allow you to work at every layer, on most API's using most tools and technologies. The advantage of this is that it will allow you to identify the complexities early. It is those complex areas that render this following statement true:
The first 90% of the code accounts for
the first 90% of the development time.
The remaining 10% of the code accounts
for the other 90% of the development
time. --Tom Cargil
Identifying, acknowledging and understanding those complex areas will allow you to manage your risks and alter your efforts and resources more effectively.
Good Luck,
Jeach!
As mentioned by MrWiggles, you may want to look into using a UI builder.
If you're looking at writing many forms, and it looks like the form data can match nicely to some javabeans, you may want to think about creating some framework panels first.
If you can create some simple base classes that take care of the wiring (syncing the fields to the beans and vice-versa), it'll save you a lot of work.
You may even want to set up some panels that will "auto create" fields based on beans. Just pass in a bean and the panel creates itself. The trick there is specifying layout for the fields, and dealing with fields that have fixed values, validation, etc. (Fixed values can be dealt with using javabean property editors - see http://javadude.com/articles/propedit/index.html.
If you're set on using Swing (eclipse RCP is nice, btw), you might want to look at the Swing Application Framework (https://appframework.dev.java.net/). If not using it directly, it may give you some ideas on how to set up bindings.
Hope this helps a bit
Are you really sure of Swing? Eclipse RCP is much better and flexible starting from EMF and going on
Anyway with Swing, first I'll prepare an XSLT template of all: common code routine and other common pieces of common to bring then them in abstract and interface classes, ORM patterns you use.
Then I'll design a common UI scheme, this "xslize" too.
After all with ANT XSLT processor I'll prepare a complete build procedure upon your specs.
P.S.
I made similar projects for simple web and swing cruds just before 2001, and if you use some peculiar UI designer you can also nest or write with xslt every specs without putting dirty code in your ui raw concepts, so when I make/add remove features on all or singular piece of code, 30 seconds maximum for full rebuild of ALL, of course you must "XSLIZE" all using also many xslt overrider/import.