I’m one of the contributors to Monkeybars, which is our JRuby GUI
framework that sits on top of Swing.
Here’s how Monkeybars handles this:
- A component consisting of a series of existing components hooked
together to act as a single widget
In Swing, it is typical to inherit from the component that gets you
closest to what you want, and add stuff to there. What you are
thinking of is probably a JPanel. While you could inherit from a
JPanel, put in the functionality or other components that you wanted,
and drop it in where you wanted to use it, we feel there’s a better
way. Monkeybars uses MVC’s delegation of responsibilities to help us
out with testing and keep the code more sensible. As such, we felt
the best way to approach this would be by providing mechanisms that
allow one MVC tuple (your top level window) to nest other MVC tuples
(reusable components). This means that controllers communicate with
other controllers. Views interact with simple view components
directly, but not complicated “partials”.
Here’s your example: An icon widget, that combines a picture and a
underneath, with config options to turn either off or size the image,
make the text editable, etc"
In Monkeybars, the picture/text field grouping would be handled by its
own model, view, and controller. This is how you’d tie that in:
class MainView < ApplicationView
simpler ones that just drops in the
you to write all code you want to
nest :sub_view => :image_name, :view => :image_name_panel
class MainController < ApplicationController
@text_image_controller = TextImageController.create_instance
# this will kick off the nesting for any nesting with a sub_view
add_nested_controller :image_name, @text_image_controller
A component built ‘from scratch’ atop a canvas, that is, handling
its own drawing and event management
Since we’re using Swing, one could override the paintComponent method
on the Swing component used in the view. We’ve done some of this to
render real-time animated graphs with peak bars and graph transitions.
We even have it so each graph bar has it’s own tooltip text.
Here’s your example: A speedometer-type dial with a configurable range
and tick interval
In this case, I’d write my own view component by hand (typically we
use a designer for it).
A speedometer could be made by using some of the Java2D stuff out
there during paintComponent. The needle could be drawn with simple
line methods where you specify start and end coordinates. The ticks
could be drawn similarly as partial lines. I’d imagine some trig would
be involved in the calculations. I would also check to see if any Java
folks had already done this, as Java/Swing have been around for a long
A component combining a canvas and existing widgets
I’d want to make the painted canvas widget into a nested controller,
so my canvas wouldn’t have to care about stomping on other components
when it redraws itself.
For your example: A box that holds a component and paints a customised
border around it
This is actually pretty simple in Monkeybars. You can just set the
boarder of many (if not all) Swing components. We have a live example
using this that you can run via Java Web Start here:
Here’s the snippet that makes the drop-shadow border happen:
@image = Java::javax.swing.JLabel.new
@image.border = Java::org.jdesktop.swingx.border.DropShadowBorder.new
The drop shadow comes from the SwingX library.
I’d also like to note that example won us the GUI part of the script
bowl competition at Java One (us being JRuby).
A container that takes a collection of widgets and lays them out
according to some userdefined algorithm
There’s a ton of ways to do this using Swing using Layouts.
Your example: A pure-ruby implementation of a wrapbox
This works out of the box just by using a FlowLayout in your
container. That can be as simple as this:
@main_view_component.layout = Java::javax::swing::FlowLayout.new
Some other stuff:
Monkeybars has a lot of options for configuring view mappings. View
mappings define how data moves from your model to the components in
your view, as well as how your components’ data moves into your model.
One thing that was really important to us in Monkeybars was that for
moderate to large projects, a large update method in a controller that
intimately knew about the components used made testing incredibly
painful. We designed Monkeybars such that most communication between
the view and controller is done through the model via the mappings
mentioned above. Controllers may also send signals to the view for
lightweight or secondary renderings. There is no direct communication,
however. This makes testing super easy.
You could write Java if you wanted, but we haven’t run into
occurrences where Java (the language) is needed. You could write all
of your designs by hand in Ruby, which is fine. My preferred approach
is to use a designer tool, such as Netbeans.
Do you really want to lay something like this out by hand?
Swing is a part of Monkeybars. We provide some simplified ways to
communicate with it (such as implicit event handlers). However,
Monkeybars doesn’t shield you from Swing. This is both a pro and a
con. Swing is a powerful library, but it also has a lot of quirks.
Thanks to the folks at JRuby, we have Rubyized methods to all of our
Java proxies, and some nice implicit type conversions that make
integrating with Java look fairly natural. Monkeybars just makes Swing
more palatable, and provides a nice quarantine zone to place all of
your Swing code (in the view).
You’re in JRuby, and that means you’re in Java. Java buys you a built-
in JIT engine. JRuby’s team has told everyone to flag occurrences
where MRI is faster as bugs. You also can run your code on any machine
with Java installed, and it’s hard to find machines without Java.
Monkeybars itself is just a jar that happens to be a library. No Ruby
installation is needed! Leveraging Rawr you can also wrap your jars
in .exes or .app files. You can even use Java Web Start to hand
someone a link and the app will auto-install/update and run. You could
also integrate Monkeybars into your existing Java app, and start
writing all of your new code in Ruby. Java also has a lot of mature
code out there, as it has been around for a long time. One personal
experience I had was using SNMP. Ruby’s SNMP library is great for
getting you started, but falls apart when you need to use the more
secure SNMPv3. SNMP4J has been around for a while, and is still active.
I know a lot of the Ruby community has some bitterness towards Java,
but this isn’t Java the language we’re using here, it’s Java the
platform. I encourage anyone interested in GUI development to take a
peak at our examples and screencasts: