And with a swing of her hips
She started to strip
To tremendous applause
She took of her drawers

And with a lick of her lips
She undid all her clips
And threw it all in the air
And everybody stared

Chris de Burgh: Patricia the Stripper

Everything after the first sentence vanishes in the distance where no-one will ever read it.

First I thought that such a plugin would need (or could at least profit from) sem***ic web technologies (no dirty words on this blog, please), but it probably wouldn’t. All we need is a global registry that maps package names to the URLs of the web interfaces of the respective source repositories. (Maybe Google Code Search could be such a repository, but its results are often pretty bad.) The plugin would also have to include a reasonably good Java parser, and maybe a heuristic to distinguish betweeen Java and non-Java text.

Why would I want such a thing? Well, I often have to dig through the code of some open source library in order to understand a bug, or just to figure out what I can do with it, and how, because the documentation is incomplete or wrong. Usually I create an Eclipse project and import the code from the source repository, but that’s quite a lot of overhead if I just need to browse the code for ten minutes or so. On the other hand, digging through source code on web pages, without the help of links between the pages, is just a nuisance.

And wouldn’t it just be so cool to have one of the most important features of an IDE as a browser plugin, enhanced by the power of the world wide web?

P.S.: Or maybe I don’t want a browser plugin – maybe I just want Google to put some more effort into Code Search? Come on, guys, you’ve got all it takes – the global repository, the parsers, the heuristics…

Problem is, that I have to use a legacy database in PostgreSQL where I am not allowed to tinker with the structure, but I am forced to insert data into the tables. The database was created using Hibernate, which means an overall database sequence is used to generate the unique IDs. Unfortunately my new pal ActiveRecord does not know anything about global Postgres sequences, so I had to figure out a way to use the hibernate sequence in a hack to get my unique IDs.

What I did was to use the hook before_validation_on_create in the ActiveRecord table model to create an ID. This looks like this:

[ruby]
class Term < ActiveRecord::Base
before_validation_on_create :generate_id

private
# use the hibernate sequence to generate the next id
def generate_id
self.id = Term.connection,execute(“select nextval(‘hibernate_sequence’)”).result[0][0]
end
end
[/ruby]

A crucial part for dynamic languages today (at least in my eyes) is the creation of domain-specific language, which Groovy also supports. Gant, for example, is a Groovy DSL for Ant scripts. Another example (take from the Tutorial Domain-Specific Languages in Groovy, PDF) I find very practical is a DSL for creating query criteria for Hibernate in the Grails framework (formerly known as Groovy on Rails, so its purpose should be clear):

def c = Account.createCriteria()
def results = c {
  like("holderFirstName", "Fred%")
  and {
    between("balance", 500, 1000)
    eq("branch", "London")
  }
  maxResults(10)
  order("holderLastName", "desc")
}

A good thing, but looks too java-y for my taste, I miss the feeling I get when using a Ruby DSL, such as SQL-DSL, for example:

statement = Select[:column1, 'book', 10].from[:table1, :table2].where do
  equal :column1, 99
  not_equal :column1, 100
  less_than :column2, 'foo'
  less_than_or_equal :column3, :column4
  greater_than :column1, 0
  greater_than_or_equal :column2, 'bar'
  like :column1, 'any'
  is_not_null :column1
  is_in :column1, [1,2]
  is_not_in :column2, [3, 4]
  exists 0
  not_exists 0
end

But maybe that’s just personal preference.

From a few first glance I get the impression, that Groovy is quite successful as a scripting sidekick to Java and I’m curious to learn more about it.

Update: I did not read the document thoroughly enough. The answers to my questions:

“We had some contact with potential teams from the Python arena, but there were not sufficiently many who were qualified enough. In the end, only one formal request for participation was submitted, so we did not admit Python into the contest.”
“It was impossible to find Ruby-on-Rails teams (“we are too busyâ€?). “

For web scraping (which I always did with Python, my absolutely favourite scripting language to date, and the fabulous BeautifulSoup library) I decided to switch to Hpricot (silly name), which does the job of scraping untidy HTML pages good enough for me.

So, what do I use as a cost-effective, well-maintained search and indexing framework? Of course Lucene, because I have grown up with Java and the bold faith that there is a library for everything under the sun – written in Java. But lately I found that there is in fact a Lucene-lookalike implementation for Ruby named Ferret. And it is even faster than Lucene. So off to new pastures.

All that is left in Java will be the RDF handling, because there is nothing as sophisticated for RDF/OWL ontology handling as the Jena library in Ruby.

Tune in next time to hear me talk about the pitfalls of weakly-typed scripting languages …

Links:

• The Python Language
• BeautifulSoup – a “dirty” HTML parser for Python
• The Ruby Language
• Hpricot – a “dirty” HTML parser for Ruby
• Apache Lucene – the de-facto open source searching standard
• Ferret – Lucene for Ruby
• Jena – a semantic web framework for Java

Not many big names are left at the home of Java. Bill Joy already went away in September 2003. How long will James Gosling and Guy Steele stick around? Makes me wonder what the future will bring for Sun and Java. Especially considering Bracha’s ominous farewell Good luck to you all – you’ll need it. Am I just being paranoid, or do these words and these events forecast a gloomy future for Sun, Java, and everyone involved, that is, me and you, my fellow programmers?

(In case you don’t know, Gilad, Josh, and Neal are Java Gods. Josh wrote the Java Collections Framework and Effective Java, one of the best books about Java. Neal Gafter was in charge of Sun’s Java compiler. Together they wrote Java Puzzlers, another great book. Gilad Bracha was heavily involved in the specification of Java itself, the JVM, Generics… you name it.)