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Tag: JRuby

Even better, even simpler multithreading with JRuby

[Yes, another post about ruby code; I’ll get back to library stuff soon.] Quite a while ago, I released a little gem called threach (for “threaded #each”). It allows you to easily process a block with multiple threads. # Process a CSV file with three threads‘data.csv’).threach(3, :each_line) {|line| send_to_db(line)} Nice, right? The problem is that I could never figure out a way to deal with a break or an Exception raised inside the block. The core problem is that once a thread trying to push/pop from a ruby SizedQueue is blocking, there’s no way (I could find) to tell…

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Using SQLite3 from JRuby without ActiveRecord

I spent way too long asking my friend, The Internet, how to get a normal DBI connection to SQLIte3 using JRuby. Apparently, everyone except me is using ActiveRecord and/or Rails and doesn’t want to just connect to the database. But I do. Here’s how. First, get the gems: gem install dbi gem install dbd-jdbc gem install jdbc-sqlite3 Then you’re ready to load it up into DBI. require ‘rubygems’ # if you’re using 1.8 still require ‘java’ require ‘dbi’ require ‘dbd/jdbc’ require ‘jdbc/sqlite3’ databasefile = ‘test.db’ dbh = DBI.connect( “DBI:jdbc:sqlite:#{databasefile}”, # connection string ”, # no username for sqlite3 ”, #…

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Why bother with threading in jruby? Because it’s easy.

[Edit 2011-July-1: I’ve written a jruby_specific threach that takes advantage of better underlying java libraries called jruby_threach that is a much better option if you’re running jruby] Lately on the #code4lib IRC channel, several of us have been knocking around different versions (in several programming languages) of programs to read in a ginormous file and do some processing on each line. I noted some speedups related to multi-threading, and someone (maybe rsinger?) said, basically, that to bother with threading for a one-off simple program was a waste. Well, it turns out I’ve been trying to figure out how to deal…

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