Develop Reference

Handle images in JSF

I am currently developing a website in which several images will be displayed on a single page. In light of performance, I'm searching for the best way to handle thes images.
First, I will explain my needs. The back-end of the website consists of a CMS in which images can be uploaded (and maybe resized by the user so the image will have the neede ratio of width/height). These images will be displayed on several pages in de website, requested by (hopefully) many users.
Secondly, I will shortly describe my environment. I am developing in Java EE, using JSF as front-end. I am using multiple libraries like Prime Faces et cetera.
I have done some research and it seems there are dozens of solutions, but I don't know in which direction to search. E.g.:
Saving images in database
Saving images as static images by using for example filestreams
So in short:
Which way of saving and requesting images would be best in this case?
What library would you advice to serve me in this?
Is there a JSF-solution to manually resize images?
Would ImageJ be the best solution to generate thumbnails? If not, what would be?
If any other details are needed, I'm happy to provide them.
Thanks in advance.

I wouldn't worry about performance until it becomes an issue. I would perhaps worry more about auditability, maintainability etc.
In order to make a future change easy, however, is abstract away your image store such that you can easily replace (say) a file-based system, with a database system (or a cloud-storage solution, or, or...).
That way you can easily substitute one for another and compare/constrast if need be, or simple swap out your implementation at a later date.

So..
Saving images as files is best
After some research it seems that PrimeFaces offers ImageCropper
File Upload can be achieved using PrimeFaces' FileUpload
But still, I have seen many discussions on Image Manipulation by Java and the best tooling for this. Some say ImageJ would be great, others don't. Is there any reason why I should go with one or another?

Procedural Map Generation

I really want to start doing a tile game, and I've started Cocos2d because of the popularity of it and the availability of tutorials and resources.
But I really want to try out some procedural map generation, but unsure if Cocos2d is the one for it.
If it comes to it and Cocos2d isn't best for this then my other options are Java or Love2D, this isn't iOS but oh well!

Because Cocos2D loads map files from an external source, what you want to do is write some code to generate a map file using the syntax described in this manual page, save the generated map file, then load it using Cocos2D's tiledMapWithTMXFile function (more information here)
for more information on writing a proccedural map generation algorithm, the Procedural Content Generation Wiki is a great resource.

A tutorial on procedurally generated caves, but it could work for top down maps and what not.
http://gamedevelopment.tutsplus.com/tutorials/cave-levels-cellular-automata--gamedev-9664

Can I draw State-Transition diagrams in JSF2 Web App?

I'm looking for a way to draw state-transition diagrams in my JSF2 project.
I would like to be able to load state and transition data and transform them in a graph that can be displayed on my web page.
I haven't found a way to do that yet. Charts available with Primefaces or MyFaces projects (I'm using the 1st one) are dedicated to statistics. In addition, it's probably possible to do that in javascript but I didn't found any example of that in the Google's API's for example.
Any suggestion or help would be appreciated.
Thanks a lot.
Clément

I doubt there are components that display graphs using plain html, but you might look for a library that generates an image which you can display in your page. That library wouldn't necessarily be JSF specific though.
Edit: maybe JUNG might be of interest for you.
In addition PrimeFaces' dynaImage might help you with displaying the generated graph image.

Getting an image from a game model

So I'm not 100% sure if it's possible, but what I'd like to do is take a model that someone has created for a game, say in Blender or something similar, in various formats, and from that create an image to show on a website.
Are there any Java libraries around that could help me with that? Java3D maybe? Or even something in Flash? Ideally you'd be able to rotate the model in some embedded flash app, but I'd settle for a plain old image.

It depends on how far you want to go. Most models are going to be in a standard format- or can easily be converted to be - and most 3D Apis are able to load these formats in.
It would be a little unusual to do this on a server - you may even need to have OpenGL installed on it - but it should be quite easy to load a model in to a 3D environment and take a snapshot or a series of snapshots quite easily. Possibly even use these to create a short video clip of a complete turn around the model. If you're using Java take a look at some of the things people are working on over at http://www.javagaming.org/ - I don't know that Java3D is in use much still but there are other good 3D java environments around. JMonkeyEngine looked most interesting last time I was exploring that area.
Alternatively you probably can set up a way of loading the model into a clientside environment - I don't know if Flash can do 3D stuff now, but Shockwave certainly can ( although it's horrible to work with ) and I believe the Silverlight stuff likewise. Of course unless you are pregenerating your animations you are likely to be passing the model to your display logic on the client and a savvy user could intercept that, but the risk is probably reasonably low and from your question it's not clear whether that would be a problem to you.

Take a look into this post:
http://techblog.floorplanner.com/2010/01/25/introducing-asblender/
"Enter ASBlender, a library I slapped together in a few days to read Blender’s .blend file format and parse it to AS3."
lucky you! ;)
EDIT: added link for the project:
http://github.com/timknip/asblender
EDIT2: With the asblender library you can parse directly the .blend file (this is the working file, not a exported file format). Once you have the file inside the flash application you can use Papervision (I believe you do the same with other 3d libraries) to render the model, this way you can do a single image of the model or you can let user to see the model rotating. Beware that any of this libraries won't give the same render quality that a 3D application like blender is capable of. The good thing about this library is the capability of reading all the info in the scene, so you can match cameras and lights to be as close as possible to the original .blend file.
Alternatively there are also other parsers like Ase, Collada , DAE, KMZ, Max3DS, MD2, Sketchup, SketchupCollada... all of this inside papervision library.

Generating and visualising a decision tree

I wonder if anyone is able to help or advise with the following; I have to be able to take data from a data source and to be able to visualise that data as a decision trees on a web page all. This will be a single process which is seamless to an end user.
This will be done using JSPs and Java servlets but what concerns me are the underlying products. I'm thinking of passing the data to a Weka classifier and then doing something with the .dot file it creates, i.e. maybe feeding it to GraphViz or trying to use the Google Visualization API to present an interactive display.
But, can anyone tell me if this is a viable approach or suggest alternatives?
Thanks
Martin O'Shea.

I've had a lot of success creating data flow graphs with graphviz (I uploaded them with a script to a MoinMoin wiki and used the graphviz plugin). That plugin even allowed to have links in the graphs, so we could keep the individual graphs small.

For the UI we have added the JS stuff from http://www.mxgraph.com/ to display larger graphs to the user.
Your approach is viable however. GraphViz is a good tool.