I would like to start a new project which will make extensive use of plugins. I know that both Eclipse and Netbeans have their respective Rich Client Platforms, both with their respective strengths and weaknesses.
I would like some comments on which the Stack Overflow community prefers.
Also, and most importantly, how easy it is with the respective platforms to write plugins for already existing applications. For example, if I finish my application, and would like to enable 3rd parties to extend it with their own plugins, how does each of these platforms provide functionality for this? Would they need my source to do it, or do these platforms provide plugin APIs towards which 3rd parties can code?
I would like some comments on which the Stack Overflow community prefers.
I lean my preference to Eclipse RCP, mostly because I still think that the IDE itself is the best right now. Eclipse RCP is also more mature, and has more books and documentations on the web. Netbeans RCP is slightly behind with only three books I can find on Amazon.com regarding the platform.
I'm also very eager to see the platform growing with its e4 projects which will simplify a lot of things (from dependency injection to UI customization)
Also, and most importantly, how easy it is with the respective platforms to write plugins for already existing applications. For example, if I finish my application, and would like to enable 3rd parties to extend it with their own plugins, how does each of these platforms provide functionality for this? Would they need my source to do it, or do these platforms provide plugin APIs towards which 3rd parties can code?
I can imagine that the answer for this question will not really be satisfying while both platform are designed to be extensible. They are pretty equals in this department.
The most important thing is to design your application to also be extensible. That is, providing extension points. You don't have to provide source code for that but you can document the extension points. Also, in case you need to provide interfaces, you can just provide the javadoc without the real source.
I repeat my point, designing application using RCP doesn't mean your application will automatically be extensible. You have to also design your application to be so. This won't come easily as you learn the platform for the first time but you will eventually learn about it from experience.
(Note: I'm not speaking for the community here ;) )
The two major differences between Netbeans and Eclipse RCP are:
OSGi (Netbeans 6.9 is only beginning to support it): it is designed to support extensions
Swing vs. SWT (can you app benefit from the native look supported by SWT)
Another factor, as you can read in this blog post is RAP (Rich Ajax Platform), which could help deploy your app on many platform based on one source code. But that may not concern you.
The maven integration is quite good from both side (see the Netbeans-RCP-Maven Hello World article), but the Maven3-Tycho integration is primarily developed on Eclipse.
Again, you might not need those new maven features (or you could use other build management system entirely, like Ivy or Graddle)
Consider if your plugins does really need such complex architecture as eclipse RCP or NetBeans provide. Plugins for RCP or NetBeans can be only created by Java Developers with strong RCP/NetBeans experience. Be aware that you can do (very easy) RCP application that is not pluggable at all. In some cases is better to write your own, maybe less flexible but more friendly way to attach new plugins. You can even do some wizards for them.
Related
I am building an Eclipse RCP application that will eventually have section for NASA Worldwind AWT component. I will be using the SWT_AWT bridge to get the worldwind component embedded in an RCP application. I am trying to decide whether I should write other components using SWT, or use Swing all the way and embed everything using SWT_AWT bridge. The latter would allow me to use Swing, but not sure what the performance implications are?
If you are going to write an RCP application then it is best to stick to the native concepts and use SWT.
When you are going to write everything in Swing then there will be a performance penalty. How much, as always, depends on the hardware you are using. With todays hardware, assuming NASA has the funds, it would not be all that relevant.
What would be more relevant is the difference in UI. SWT renders with native widgets, Swing does not.
A good read is this article on the Swing in RCP [1]
[1] http://www.eclipse.org/articles/Article-Swing-SWT-Integration/
At the moment Iam evaluating java web frameworks. More precisely Iam talking about GWT, JSF2 and apache wicket. One very importent criteria in this evaluation is prototyping.
The prototyping process in my company can be described by the folloing:
The customer can produce GUIs with an easy to use WYSIWYG editor, by drag&drop-ing web components on the corporate predefined website structur. There is also a need for some litte dynamic being like navigation from one frame to another.
So Iam looking for tools. These tools should not only provide nice GUIs but also deliver
some basic code, which can be forwarded to the development. The aim is to avoid missunderstandings between designers and developers as much as possible. More or less the
developers just have to implements the code, but not to implement the optical requirements.
In addition it would be desirable to customize the components thats been used in the WYSIWYG editor. Does anyone know any good tools for the mentioned frameworks (GWT, JSF2, wicket)?
One of the challenges with WYSIWYG tools for UI is that you generally have to pick between rapid prototyping and maintainable code. Even then, as soon as you want to do something that's not supported by the prototyping tool, you can implement it as you would without the prototyping tool, but your round-trip functionality (namely turning your app back into something that can be edited) is broken or crippled unless extra work is done to generate the metadata that the editor needs.
Upgrading between major releases is another issue. Vendors and groups who have developed these tools have a historically spotty record of when they stop supporting older versions, reasonably because of limited resources and sometimes difficult problems with how to track solid innovation happening in the framework itself.
My suggestion instead is to prototype with an RIA prototyping tool like Balsamiq Mockups or use a grid system like 960 Grid to generate rapid prototypes, then use a web development framework that allows your developers to run the code with or without the backend server. Wicket has a tag called that is great for this kind of thing -- web devs can fill a div with stuff that a component should generate, and Wicket devs can wrap the contents of that tag with after they implement it. Both parties can coexist for a long time that way.
Try GWT Designer for GWT.
Introduction
Quick Start Guide
Download
There's nothing like this for Wicket that I know of. The closest you would get to any kind of resource reuse from your customer would be to give them a drag and drop HTML editor - the resulting HTML could then form the basis of Wicket page/panel layout.
if you are planing to use a javascript library, you may use extjs,
http://www.sencha.com/products/js/
they have developed a nice designer
www.sencha.com/products/designer/
there is also a port of ext in GWT
www.sencha.com/products/gwt/
You have to pay for a commercial license if your application isn't open source!
A repeating theme in my development work has been the use of or creation of an in-house plug-in architecture. I've seen it approached many ways - configuration files (XML, .conf, and so on), inheritance frameworks, database information, libraries, and others. In my experience:
A database isn't a great place to store your configuration information, especially co-mingled with data
Attempting this with an inheritance hierarchy requires knowledge about the plug-ins to be coded in, meaning the plug-in architecture isn't all that dynamic
Configuration files work well for providing simple information, but can't handle more complex behaviors
Libraries seem to work well, but the one-way dependencies have to be carefully created.
As I seek to learn from the various architectures I've worked with, I'm also looking to the community for suggestions. How have you implemented a SOLID plug-in architecture? What was your worst failure (or the worst failure you've seen)? What would you do if you were going to implement a new plug-in architecture? What SDK or open source project that you've worked with has the best example of a good architecture?
A few examples I've been finding on my own:
Perl's Module::Plugable and IOC for dependency injection in Perl
The various Spring frameworks (Java, .NET, Python) for dependency injection.
An SO question with a list for Java (including Service Provider Interfaces)
An SO question for C++ pointing to a Dr. Dobbs article
An SO question regarding a specific plugin idea for ASP.NET MVC
These examples seem to play to various language strengths. Is a good plugin architecture necessarily tied to the language? Is it best to use tools to create a plugin architecture, or to do it on one's own following models?
This is not an answer as much as a bunch of potentially useful remarks/examples.
One effective way to make your application extensible is to expose its internals as a scripting language and write all the top level stuff in that language. This makes it quite modifiable and practically future proof (if your primitives are well chosen and implemented). A success story of this kind of thing is Emacs. I prefer this to the eclipse style plugin system because if I want to extend functionality, I don't have to learn the API and write/compile a separate plugin. I can write a 3 line snippet in the current buffer itself, evaluate it and use it. Very smooth learning curve and very pleasing results.
One application which I've extended a little is Trac. It has a component architecture which in this situation means that tasks are delegated to modules that advertise extension points. You can then implement other components which would fit into these points and change the flow. It's a little like Kalkie's suggestion above.
Another one that's good is py.test. It follows the "best API is no API" philosophy and relies purely on hooks being called at every level. You can override these hooks in files/functions named according to a convention and alter the behaviour. You can see the list of plugins on the site to see how quickly/easily they can be implemented.
A few general points.
Try to keep your non-extensible/non-user-modifiable core as small as possible. Delegate everything you can to a higher layer so that the extensibility increases. Less stuff to correct in the core then in case of bad choices.
Related to the above point is that you shouldn't make too many decisions about the direction of your project at the outset. Implement the smallest needed subset and then start writing plugins.
If you are embedding a scripting language, make sure it's a full one in which you can write general programs and not a toy language just for your application.
Reduce boilerplate as much as you can. Don't bother with subclassing, complex APIs, plugin registration and stuff like that. Try to keep it simple so that it's easy and not just possible to extend. This will let your plugin API be used more and will encourage end users to write plugins. Not just plugin developers. py.test does this well. Eclipse as far as I know, does not.
In my experience I've found there are really two types of plug-in Architectures.
One follows the Eclipse model which is meant to allow for freedom and is open-ended.
The other usually requires plugins to follow a narrow API because the plugin will fill a specific function.
To state this in a different way, one allows plugins to access your application while the other allows your application to access plugins.
The distinction is subtle, and sometimes there is no distiction... you want both for your application.
I do not have a ton of experience with Eclipse/Opening up your App to plugins model (the article in Kalkie's post is great). I've read a bit on the way eclipse does things, but nothing more than that.
Yegge's properties blog talks a bit about how the use of the properties pattern allows for plugins and extensibility.
Most of the work I've done has used a plugin architecture to allow my app to access plugins, things like time/display/map data, etc.
Years ago I would create factories, plugin managers and config files to manage all of it and let me determine which plugin to use at runtime.
Now I usually just have a DI framework do most of that work.
I still have to write adapters to use third party libraries, but they usually aren't that bad.
One of the best plug-in architectures that I have seen is implemented in Eclipse. Instead of having an application with a plug-in model, everything is a plug-in. The base application itself is the plug-in framework.
http://www.eclipse.org/articles/Article-Plug-in-architecture/plugin_architecture.html
I'll describe a fairly simple technique that I have use in the past. This approach uses C# reflection to help in the plugin loading process. This technique can be modified so it is applicable to C++ but you lose the convenience of being able to use reflection.
An IPlugin interface is used to identify classes that implement plugins. Methods are added to the interface to allow the application to communicate with the plugin. For example the Init method that the application will use to instruct the plugin to initialize.
To find plugins the application scans a plugin folder for .Net assemblies. Each assembly is loaded. Reflection is used to scan for classes that implement IPlugin. An instance of each plugin class is created.
(Alternatively, an Xml file might list the assemblies and classes to load. This might help performance but I never found an issue with performance).
The Init method is called for each plugin object. It is passed a reference to an object that implements the application interface: IApplication (or something else named specific to your app, eg ITextEditorApplication).
IApplication contains methods that allows the plugin to communicate with the application. For instance if you are writing a text editor this interface would have an OpenDocuments property that allows plugins to enumerate the collection of currently open documents.
This plugin system can be extended to scripting languages, eg Lua, by creating a derived plugin class, eg LuaPlugin that forwards IPlugin functions and the application interface to a Lua script.
This technique allows you to iteratively implement your IPlugin, IApplication and other application-specific interfaces during development. When the application is complete and nicely refactored you can document your exposed interfaces and you should have a nice system for which users can write their own plugins.
I once worked on a project that had to be so flexible in the way each customer could setup the system, which the only good design we found was to ship the customer a C# compiler!
If the spec is filled with words like:
Flexible
Plug-In
Customisable
Ask lots of questions about how you will support the system (and how support will be charged for, as each customer will think their case is the normal case and should not need any plug-ins.), as in my experience
The support of customers (or
fount-line support people) writing
Plug-Ins is a lot harder than the
Architecture
Usualy I use MEF. The Managed Extensibility Framework (or MEF for short) simplifies the creation of extensible applications. MEF offers discovery and composition capabilities that you can leverage to load application extensions.
If you are interested read more...
In my experience, the two best ways to create a flexible plugin architecture are scripting languages and libraries. These two concepts are in my mind orthogonal; the two can be mixed in any proportion, rather like functional and object-oriented programming, but find their greatest strengths when balanced. A library is typically responsible for fulfilling a specific interface with dynamic functionality, whereas scripts tend to emphasise functionality with a dynamic interface.
I have found that an architecture based on scripts managing libraries seems to work the best. The scripting language allows high-level manipulation of lower-level libraries, and the libraries are thus freed from any specific interface, leaving all of the application-level interaction in the more flexible hands of the scripting system.
For this to work, the scripting system must have a fairly robust API, with hooks to the application data, logic, and GUI, as well as the base functionality of importing and executing code from libraries. Further, scripts are usually required to be safe in the sense that the application can gracefully recover from a poorly-written script. Using a scripting system as a layer of indirection means that the application can more easily detach itself in case of Something Bad™.
The means of packaging plugins depends largely on personal preference, but you can never go wrong with a compressed archive with a simple interface, say PluginName.ext in the root directory.
I think you need to first answer the question: "What components are expected to be plugins?"
You want to keep this number to an absolute minimum or the number of combinations which you must test explodes. Try to separate your core product (which should not have too much flexibility) from plugin functionality.
I've found that the IOC (Inversion of Control) principal (read springframework) works well for providing a flexible base, which you can add specialization to to make plugin development simpler.
You can scan the container for the "interface as a plugin type advertisement" mechanism.
You can use the container to inject common dependencies which plugins may require (i.e. ResourceLoaderAware or MessageSourceAware).
The Plug-in Pattern is a software pattern for extending the behaviour of a class with a clean interface. Often behaviour of classes is extended by class inheritance, where the derived class overwrites some of the virtual methods of the class. A problem with this solution is that it conflicts with implementation hiding. It also leads to situations where derived class become a gathering places of unrelated behaviour extensions. Also, scripting is used to implement this pattern as mentioned above "Make internals as a scripting language and write all the top level stuff in that language. This makes it quite modifiable and practically future proof". Libraries use script managing libraries. The scripting language allows high-level manipulation of lower level libraries. (Also as mentioned above)
I need to write a GUI for a Java desktop application and I want to use something more / better than Swing. What is the learning curve for the NetBeans RCP like? The learning curve for Eclipse RCP is so bad that it's not worth considering:
"Right now, after one week of training, a RCP newbie just touched the very basic things of RCP. This is one reason why many big industry companies have problems adopting RCP. "
http://wiki.eclipse.org/E4/RCP_Future
Is the learning curve for NetBeans RCP considerably less?
Thanks.
Dean
We've had a summer intern working on an application based on the Netbeans RCP and it's been going really well. Because it's mainly swing, lots of your existing knowledge is directly applicable. You can still use tools such as the Matisse GUI builder and just need to learn a few patterns to get lots of benefit from the RCP.
The book The definitive guide to the Netbeans Platform is an excellent reference/tutorial and is reasonably up to date.
It's also worth checking out Geertjan's Blog - he's the technical author of the Rich Client Platform documentation and his regular blog posts form a Netbeans RCP cookbook.
I spent about four days writing a swing application and was able to port it into a NetBeans Platform app in about three days. I've done some Eclipse RCP and I can say it is much easier using the NetBeans Platform. I'm still new at NetBeans Platform but i'm pretty sure at this point if i were to write a complex application wo putting too much time into it I'd start with the NetBeans platform first. I was also using Heiko Bock's "The Definitive Guide to NetBeans Platform 7"
I doubt that the inherent complexity is dramatically different between any GUI libraries of substantial size. Since Netbeans RCP is actually Swing-based (with a better platform-look-and-feel on Windows, I think), the learning curve might be somewhat flatter for you, since you already know Swing.
"Right now, after one week of training, a RCP newbie just touched the very basic things of RCP. This is one reason why many big industry companies have problems adopting RCP. "
This may or may not be correct, but consider that in some cases (i.e. no fancy graphics/canvas/3D/bitmap manipulation), just plain old dialogs/forms go a long way. The critical parts to master are (in my opinion) the list/tree-models and the general data-binding mechanisms and to find, learn and stick to a layout manager that works (MigLayout is superb and has backends for Swing and SWT).
I am about to start on a college project (a web application) and I have never used a full-fledged IDE such as Eclipse.
Turbo C/C++, Visual Basic 6,Java Basic, a bit of SQL, ASP, etc is the sort of exposure I have.
What things should I keep in mind before starting my project using Eclipse? Are the tools mentioned appropriate for the project?(If not please give a detailed answer)
Designing - UML (Rational Rose)
Language - Google Web Toolkit
Server - Google App Engine
IDE - Eclipse
Version Control - Subversion or Mercurial?
I would definitely recommend Googling first. There are a number of tutorials regarding Eclipse as it is a very popular IDE. A quick Google search of my own brought up all these results: developing web applications in eclipse
As for other things to consider, if you are developing a web application, you'll need:
web server (Tomcat is a popular one)
possibly a database (MySQL is an open source, easy to use DB)
language (I'm assuming you're going with Java since you are using Eclipse)
Of course, you'll also need to consider how you hook everything together and what technologies you want to use to do that. (Hibernate, Spring, etc) Eclipse itself has a ton of plugins to help bring together all these various aspects.
That list from Wikipedia is a good and comprehensive list, but if you are learning or developing on your own machine, you may not necessarily need all of that.
Hope that helps.
Since it is a web application, then start with the looks of it.
First, layout a template of how your pages should look, that is what users see. If it does not look good, the users will think the application (in its entirety) is also not good (it does not matter if the code behind the view is perfect; it will just make a first bad impression).
Start with that and be consistent with the design in all your pages. SiteMesh is a nice tool to dissociate the looks of the page from the functionality you put in it.
Then think what the application will do and what it will use:
you have a database? (use something like MySQL). With what are you going to access it? (IBatis is nice; Hibernate I think is a bit heavy weight for a first project)
you need a server: Tomcat is easy to use;
are you going for a simple Servlet/JSP approach or you want to use a framework (look at Spring or Struts);
try to find the good ways of writing the application, look at service layers, DAO pattern, DTO, MVC. Also, you must understand how HTTP works.
A lot more could be said.
Ah.. and also use a source repository. It’s a must (even if you work alone on this project).
Eclipse can handle all of these tools, but then so can Netbeans.
For your first project with GWT you should read through this tutorial:
http://code.google.com/webtoolkit/tutorials/1.6/gettingstarted.html
If you don't know Java then you will have some learning to do, and unlike Visual Studio your UI won't be just drag and drop, so it will be a bit harder than you are used to.
Subversion is fine, it is a nice source control, and any IDE will work with it.
Depending on your project would determine if GWT is the best choice though.
I expect UML may be overkill, and if you were following an agile methodology you wouldn't use it.
Your best bet is to get the UI done first, just have it appear as you want, and have some fake results, until you are happy with the look and feel.
Then, start to do the wiring to whatever you need on the backend.
Don't mean to be harping on you, but is Eclipse a must? For myself, in the beginning NetBeans turned out to be a really painless introduction to getting a web project up a running fast. I believe in the beginning one will spend a lot less time fighting the IDE with NetBeans.
A lot of the items from your bullet list NB makes super easy to ramp up as well. Just my $0.2