Fresh and Crispy

Java Technology Concept Map

2004-06-30T17:38:00+00:00

This interactive diagram to the Java universe is a flash application that links to the documentation. I thank Malcolm Davies on Java.Net for drawing our attention to this excellent resource.
In a nutshell:

"Developers learn and use Java to create and run Programs that make Devices and the Internet useful for People."

UMLet - Another Free UML Tool

2004-06-25T15:42:00+00:00

Martin Fowler mentioned UMLet in his recent article on UmlSketchingTools which I blogged about earlier this week. A paper in which the authors (Auer et al, 2003) describe the ideas behind UMLet is very insightful and pretty much echoes my own experiences of over-blown UML tools in the teaching domain (and I’ve tried ArgoUML, Poseidon CE, Together and Rational Rose with variable — but mostly limited — success over the last three or four years).

I have to say that, although it currently only supports class, object and use-case diagrams, UMLet looks very promising and may well prove to be a winner in next year’s Software Engineering courses. Better yet, UMLet can be used as an Eclipse plugin!

Reference

M. Auer, T. Schurtschenthaler, and S. Biffl (Vienna University of Technology), 2003. A Flyweight UML Modeling Tool for Software Development in Heterogeneous Environments”, 29th Euromicro Conference (EUROMICRO’03), Sept. 01–06. Balek-Antayla, Turkey. Conference Proceedings Published by IEEE.

Python development with Eclipse and Ant

2004-06-25T15:16:00+00:00

Excellent article by Ron Smith on IBM developerWorks on how to set up and use Python with Eclipse and Ant. Will definitely be using this to set up Eclipse 3.0 with Python support when the final version is released.

New Ant 1.6 Features for Big Projects

2004-06-24T17:07:00+00:00

A new tutorial article by Stefan Bodewig on the OracleTM Technology Network has been brought to my attention by a news article on TSS (thanks Sudhakar Ramakrishan). Describes the new , and tasks that should make ant even better! Will print and read the detail later, but I can’t wait to try some of these out on the EG-140 build (which needs all kinds of scripting tricks to work).

UmlSketchingTools

2004-06-16T22:56:00+00:00

Another approach to UML diagramming. This time publicised in Martin Fowler’s Blicki: MF Bliki: UmlSketchingTools. UMLGraph uses a mixture of JavaDoc tags and pic macros to do the hard work. Dr Spinelis argues for his declarative approach in “On the Declarative Specification of Models, IEEE Software, 20(2):94-96, March/April 2003 which is on-line in PDF format at http://www.spinellis.gr/pubs/jrnl/2003-IEEESW-umlgraph/html/article.html. Worth a look I think — as is the author’s (Domidis Spinellis) book Code Reading.

Visual Thought

2004-06-15T10:14:00+00:00

Jeremy Rayner’s June 15 blog entry directed me to another free drawing tool for UML diagrams. Thanks for the link!

I mentioned violet a couple of days ago. It is really simple, unfortunately it doesn’t have the ability to move classes around once positioned. This makes it a a bit hard to use. It is open source so that could be fixed of course!

Visual Thought is a drawing tool so it has the same advantages as Visio in that it’s not designed for MDA or for code generation, so you can happily use it for agile modelling. As I have some modeling to do over the summer as I rewrite my Client-Server Programming in Java Module, I’ll let you know how it goes!

jMock - A Lightweight Mock Object Library for Java

2004-06-02T09:14:00+00:00

Version 1.0.0 jMock – A Lightweight Mock Object Library for Java has been released. jMock is a framework that uses reflection (I assume) to programmatically define mock objects for unit testing. Tutorials and source code ready for downloading.

The Ted Neward Challenge (AOP without the buzzwords)

2004-06-02T09:07:00+00:00

Adrian Colyer has tried to describe AOP without using the buzzwords. An attempt to answer a challenge thrown down at the last TSS symposium in The Aspects Blog. It boils down to DRY (don’t repeat yourself).

So what we’ve really got in any non-trivial software application is not the ideal 1-to-1 mapping between concept and implementation, but an n:m mapping. No wonder software gets so hard to maintain, and so hard to understand, and so complex. And it’s not your fault. The tools that object-oriented languages give us don’t enable the clean mapping of every design concept into a single implementation construct … and consequently neither do they allow each implementation construct to map cleanly onto a single design concept. This is the problem that aspect-oriented programming attempts to help us solve. It’s about getting as close to a 1-to-1 mapping as we can. AOP addresses the problem by introducing a new construct known as an aspect that is able to capture in one place the implementation of design requirements, such as the view-notification requirement [all views have to be notified if the model > >

changes] in MVC, which OOP cannot.

Not the next big thing! SSS (Small, Simple, Safe) reinvents BlueJ functionality

2004-05-27T16:25:00+00:00

Daily trawl through the java.blogs feeds picked up a reference to ONJava.com: SSS (Small, Simple, Safe) [May. 26, 2004]. SSS is apparently a simple tool that allows you to instantiate and play with Java objects. It is apparently used and useful in teaching. I simply had to make a comment to the effect that BlueJ has had this feature for ever! Here’s my response in full:

BlueJ is a simple Java IDE (avalable from www.bluej.org) which also has this sort of behaviour. You can instantiate an object of any class on the classpath by providing the fully qualified name and then selecting any of the class’s constructors. Once the object has been instantiated and a small icon (sort of like a UML object diagram) appears. You can then right-click on the “object” to call any of the object’s methods. Because BlueJ is an IDE and debugger it has privileged access to the JVM, which allows you to also inspect the object to see all its private state.

BlueJ has built up quite a following in the educational arena just lately and there are several “CS101″ text books using it (but none from O’Reilly). See the web site quoted above for more info and access to the lively discussion lists.

It’ll be interesting to see if there is any feedback!

Everybody's Blogging about Eclipse M9

2004-05-24T19:07:00+00:00

Lot of traffic on the blogosphere about the new Milestone 9 release of Eclipse. Here’s a memo to self to check this out later.

Keep it DRY, keep it shy and tell the other guy

2004-05-24T17:07:00+00:00

Andy Hunt and Dave Thomas The Pragmatic Programmers have published a brilliant article with the above title in Andy Hunt and Dave Thomas, “OO in one sentence: Keep it DRY, Shy and Tell the Other guy”, IEEE Software, Vol.21 No. 3, pp 101–103, May/June 2004. In outline their main points are:

DRY (don’t repeat yourself) states:

Every piece of knowledge must have a single, unambiguous, and authoritative representation representation within a system. (Hunt and Thomas, The Pragmatic Programmer, Addison Wesley, 2000.)

Non-authoritative information (e.g. for EJB all the various interfaces and configuration files) should ideally be generated from the authoritative sources. The DRY principle also applies to build process, code reviews, and documentation.

Shy means code should not reveal information about itself unless really necessary. There are four axes of undesirable coupling that violate the Shy principle:
static coupling occurs when a program module needs another to compile. Some coupling is often necessary, but it should be minimized. Inheritance is a particularly nasty source of unanticipated coupling and delegation (uses a, has a) is often preferable to is a.
dynamic coupling occurs when a class needs the services of another class. A good example of what can go wrong is code like auction.getLot().getHighestBid().getBidder().getPerson() (called a train wreck that appears in one of my lab exercises. The client (auction) needs to know too much about its collaborating classes and is therefore fragile.
Domain coupling occurs when too much information about business logic appears in code. It can often be reduced by the judicious use of meta data that is kept in properties or databases.
Temporal coupling occurs when code execution is dependent on a particular execution order. Code that may one day be expected to run concurrently should be designed to be concurrent.

A corollary of shy code is that code should not be nosy (could be paraphrased as mind your own business!

Tell the Other Guy [or Tell, Don’t Ask (IEEE Software, Jan/Feb 2003)]. Don’t think of methods as function calls rather as sending a message. Make the other class responsible for providing a service, don’t expect a data return!

Great stuff as usual and well worth quoting in all my software engineering courses!

While on this note it’s probably worth noting that the Pragmatic Programmers are also bloggers: Andy Hunt blogs in Andy’s Weblog and Dave Thomas as PragDave. Both are on my Blog roll at Bloglines.com.

Jam Tomorrow

2004-05-21T15:20:00+00:00

Something to look into:

"JAM leverages the new import and target override features of Ant 1.6 to create a reusable, consistent Java build framework. JAM modules support JBoss, XDoclet, JUnit, Cactus, Struts, Castor, Resin and MDA/UML code generation. Maven’s POM and repository features are supported via a Maven-to-Ant bridge."

Thanks to New Build Tool: J2EE + Ant = JAM on theServerSide.

Faking the pass-by-reference semantics

2004-05-21T12:02:00+00:00

Nice blog article about Java’s pass-by-reference semantics. I still think Kathy Sierra’s Campfire Story Pass-by-Value Please is a good an explanation of this difficult concept as you’ll find. And it’s nice and memorable. Kathy and Bert Bates make good use of the analogy in Head First Java too.

Thanks to Val’s Blog.

Using Velocity with Jython

2004-05-20T12:41:00+00:00

I need to develop a web application to allow student upload of Java programs for testing. A Jython servlet with some form of template engine for presentation may be part of the solution (full framework J2EE application seems overkill!). I came across several interesting articles after a simple Google search for Velocity and Jython. This one is definitely worth another look later: Pythlet.