Brennan Spies's blog

Java dependency injection just got better: Google Guice 2.0 has been released.

What's new:

• Provider methods. You can now annotate methods in your Module so you avoid manually constructing dependencies.
• Binding overrides. One Module can now override the bindings in another.
• Private modules. You can now create bindings that are not externally visible, in order to encapsulate your dependency injections.
• The ability to inject members of sets and maps using Multibinder and MapBinder respectively.
• ServletModule now provides programmatic configuration of servlets and filters. GuiceServletContextListener can be used to help bootstrap a Guice application in a servlet container.
• Custom injections. Guice now includes hooks that allow other frameworks to define custom injection annotations. This enables Guice to host other frameworks that have their own injection semantics or annotations.
• A tree-like structure for Injectors, i.e., an Injector can have children that inherit all of its bindings.
• An introspection API: like reflection but for Guice bindings.
• Pluggable type converters that convert constant string bindings to other types, i.e., Dates, URLs, etc.
• OSGi compatible. Guice now works well in OSGi managed environments, because AOP-generated classes use a bridge classloader.
• AOP is now optional, so Guice will work on platforms that don't support bytecode generation (Android).

You can download the new release here. The new manual is here. Now all they have to do is update the public Maven repository.

javax.inject.Inject

On related news (Crazy) Bob Lee, the creator of Guice, and Rod Johnson, the creator of Spring, have gotten together to propose a standard set of annotations and interfaces for using dependency injection in Java under the banner of JSR-330: Dependency Injection for Java (still only a proposal, so JSR-330 is a tentative moniker). There is also a corresponding project over at Google Code. The standardization should greatly help the use of dependency injection in shared 3rd party libraries, allowing the application developer to avoid having to initialize more than one dependency injection framework.

These annotations are modelled closely on those currently in Google Guice:

• @Inject - Identifies injectable constructors, methods, and fields
• @Qualifier - Identifies qualifier annotations
• @Scope - Identifies scope annotations
• @Named - String-based qualifier
• @Singleton - Identifies a type that the injector only instantiates once

The utility interface Provider is also in the proposed specification.

Plugins and extensions for Google Chrome have arrived. As of developer build 2.0.180.0 of Chrome, the browser is now extensible. A page showing how to create extensions recently went up on the Chromium project documentation site as well as some samples--including a Gmail checker. A recent developer release is required to try out the functionality.

The main document page for Chrome extensions is here. Support for extensions is still very early stage, so they are not yet ready for general consumption.

E-Books has compiled a sizeable list of programming books that are available free for download or online viewing. Topics include Ada, Assembly, C/C++, C#, Haskell, Java, JavaScript, LISP, Perl, Python, Ruby, Visual Basic, and XML.

You can view the list here. My favorites? The Structure and Interpretation of Computer Programs, Thinking in Java, Programming Ruby, and Communicating Sequential Processes. But I haven't read all of them--yet :).

The first "stable" release of Clojure has been announced. Clojure, a dialect of Lisp built for the JVM, is one of the few languages with built-in Software Transactional Memory (which I describe in more detail here).

There is also a TODO list of desired features targeted for the 1.1 release.

You can download the 1.0.0 release here.

After living on my hard drive for a few months, I finally decided to give my new project a home: http://code.google.com/p/workhorse/ (I literally checked in the initial code today). It's very alpha right now, but the general ideas are starting to take shape.

What is WorkHorse?

WorkHorse is a BPM engine written in Java. It is meant to be both lightweight (i.e., embeddable) and powerful. By the time that I am done, I hope to prove that you don't need to force-fit BPM into BPEL, or even have a heavy-weight XML process description layer at all.

The idea for the project originated with some of the concepts/ideas in BPMN, which I like, though I recognize its weaknesses. Workflow (I am using the older, less trendy term) is a natural fit for so many types of applications, but it often seems that developers avoid it because existing solutions are too cumbersome: they force you to run them on some proprietary server, or they are simply a headache to configure and embed in your existing application.

Can WorkHorse alleviate this headache? Stay tuned.

Oracle announced today that it will buy Sun Microsystems for $7.4 billion, finally ending Sun's search for a suitor. Oracle, a heavy investor in Java technology even prior to its purchase of BEA Systems, was a natural choice after Sun's courtship with IBM failed. As the resident "Java guy" around here, I'd be remiss if I did not share some of my own perspective on the big news.

First, the things I see as being positive:

• This is good for Java, at least the perception of Java in the marketplace. Fair or not, there are many people who equate business success with quality (just ask your friendly SharePoint administrator). A nose-diving Sun stock price did not do much for people's perception of the viability of Java as a platform going into the future. Oracle's stewardship should improve this dramatically.
• Like IBM, Oracle has always done a much better job than Sun actually making money on Java. Of course one could speculate endlessly on the reasons why (one invariably hears the fuzzy term "marketing"), but the fact remains: Sun executives chased the buzzword of the day while Oracle executives made money. In what reminds me of Apple in the late 90's, this is not uncommon in "R&D-oriented" companies; they just don't seem to learn how to sell the technology very well.
• Solaris. Long viewed as one of the best flavors of Unix (featuring DTrace and ZFS, to name a few cutting-edge technologies), Solaris is the other crown jewel that Oracle picked up in the merger. In the conference call following the announcement, Larry Ellison specifically named Solaris as one of the reasons for the move. Since both Oracle and Weblogic already run on Solaris, owning the OS itself opens up some possibilities for Oracle.
• Having followed Oracle's acquisition of BEA, I was generally impressed by the fact that Oracle did not automatically favor its own product lines over BEA's. In fact, a lot of careful thought seemed to go into which technology Oracle would adopt going forward. I hope the same will be true for Sun.

And now the less positive:

• Consolidation. Consolidation is usually a good thing for vendors (at least the winners), and not so much for customers. There is, of course, less choice and inevitably some "cool stuff" that you wanted to last forever winds up in the dustbin.
• MySQL. The MySQL community is unlikely to be very happy about the merger, given its traditional positioning as a cheaper alternative the the dominant database vendor. Personally speaking (and I'm no expert on the database market), I think that MySQL occupies a different end of the market than Oracle does, one which the the database giant would be foolish to ignore. Oracle is likely to keep selling Oracle database to its "Fortune 500" customers while also selling MySQL support to lower-end customers running LAMP stacks. The good news is that MySQL will remain a light-weight database. The bad news is that "enterprise features" are likely to fall off the development roadmap.
• Glassfish. Sun was doing some very interesting work with Glassfish, and it's hard to say what will happen to the project in the wake of the Oracle purchase. Will it simply get nuked in favor of Weblogic? Glassfish has not yet seen huge adoption in the marketplace, so it may not have the same argument in favor of it that MySQL does. There is a big question mark hanging around its neck now--which is a shame because Glassfish is the kind of light-weight JEE server that could really be a game-changer if marketed properly.
• Hardware. Sun is still very much a hardware company (at least in terms of revenue); Oracle is not. It's hard to say what will become of some of Sun's high-end hardware business after the acquisition. Personally, I think that Oracle will try to sell it off to a more hardware-oriented company in order to mitigate the cost of the buy.

Of course, this is all just speculation, and it is fun to speculate at times like these. One thing, though, is for sure: in the face of a bad economic recession, the market for enterprise technology will continue to consolidate.

Also known as ECMAScript 5th Edition, the new JavaScript standard has entered final draft stage. Among the goodies: a formal getter and setter syntax for object properties, language reflection features, support for the JSON data format, additional Array methods, and a strict mode that improves error checking.

Function.bind

Function.prototype.bind(self, args...). A bind function wraps a function in a closure, storing references to the context arguments from the surrounding scope. This is somewhat equivalent to the following:

Function.prototype.bind = function(context) {
  var fun = this;
  return function(){
    return fun.apply(context, arguments);
  };
};

Applications include partial application of arguments to a function and currying. Though you can custom-roll one today, a native bind function in 3.1 should outperform any equivalent user-defined function.

Array

The additional Array methods in ECMAScript 3.1 are identical to methods introduced in JavaScript 1.6-1.8, but were never present in any official ECMAScript specification. They are currently implemented in Firefox 3.x. Of course, having them in ECMAScript 3.1 means that now you will be able to actually use them (provided, of course, that all browsers implement the standard...). These methods are: indexOf, lastIndexOf, filter, forEach, every, map, some, reduce, and reduceRight. There's a good description of each method here.

ECMAScript 3.1, also known as JavaScript Harmony, is the less ambitious version of what was to be JavaScript 2/ECMAScript 4, a plan scuttled when some members of ECMA balked at the large additions to the language.

The new specification is available here.

Hot on the heels of the announcement that Java can now be used with the Google App Engine, the Google Plugin for Eclipse has been released, supporting both Google Web Toolkit and Google App Engine development.

GWT Features:

• Recognition of inline JavaScript (JSNI): syntax highlighting, auto-indenting, Java Search and Refactoring integration
• GWT compiler shortcuts and configuration UI
• Wizards to create entry points, modules and HTML pages
• Support for GWT JUnit tests

App Engine Features:

• Easy deployment to App Engine
• As-you-type validation ensures that your code is compatible with App Engine
• Build projects and 'enhance' JDO classes automatically without the need for ANT

The user's manual for the plugin is here. The plugin works with both Eclipse 3.4 (update site) and 3.3 (update site).

The 1.3 version of the Dojo toolkit is finally out. The main focus of this release has been browser compatibility (particularly IE 8 and Chrome) and speed. According to Dojo-reported numbers on the TaskSpeed benchmark, Dojo is the fastest JavaScript toolkit on common DOM operations, at least twice as fast as other JavaScript toolkits. Of course, all the usual caveats about micro-benchmarking apply, but the speed increase is nevertheless quite impressive.

Simultaneous with the Dojo 1.3 release is the release of the PlugD, a library allows Dojo developers to mimic some of the popular aspects of jQuery (method chaining, as well as many similarly-named convenience methods).

The full release notes can be found here. You can download the new release here.

Explorer Canvas, otherwise known as the little JavaScript library that allows you to use VML while still coding in HTML 5 Canvas (thank heaven), has released the third version of the library. The major reason for the release is compatibility with Internet Explorer 8, but there are numerous other bug fixes and improvements in the release. A comprehensive list of changes is here.

You can download the new release here.