Mollusca Code

Import Puts Noise In My Class

Today I stumbled accross something like this:

class SwtBuilder

  import org.eclipse.swt.widgets.Display
  import org.eclipse.swt.widgets.Shell
  import org.eclipse.swt.widgets.Button
  import org.eclipse.swt.widgets.Canvas
  import org.eclipse.swt.SWT

  import ch.mollusca.foo.Bar
  import ch.mollusca.foo.Jiffy

  def build
    puts SWT::BOLD | SWT::ITALIC
  end

end

SwtBuilder.new.build

Alas, jRuby doesn’t support

import org.eclipse.swt.widgets.*

there is plenty of noise throughout this class definition. It’s a lot of vertical clutter and I don’t like it. This will even get worse for any class that ties together a few java classes.

Enter Importer

I tried to figure out a way to clean this up. Maybe I’ve hit the spot, but I think it’s not quite there yet. Anyway:

module Importer

  module ClassMethods
    def importer(hash)
      unless hash[:path] && hash[:items]
        puts "need to specify path and items!" 
      else
        hash[:items].each do |item|
          path = hash[:path] + "." + item
          import path
        end
      end
    end
  end

  def self.included(receiver)
    receiver.extend ClassMethods
  end

end

This allows me to write:

class SwtBuilder

  include Importer
  importer :path => 'org.eclipse.swt.widgets', \
    :items => ['Display', 'Shell', 'Button', 'Canvas']
  importer :path => 'org.eclipse.swt', :items => ['SWT']

  def build
    puts SWT::BOLD | SWT::ITALIC
  end

end

SwtBuilder.new.build

It’s formatted in two lines for layout reasons, but in principle can nicely be written on one line. Any comments on the idea?