Jasper Report implementation in JRuby

ticket.rb

Jasper reports 5.5
require "#{Rails.root}/lib/jar/jasperreports-5.5.0/jasperreports-5.5.0.jar"
Dir["#{Rails.root}/lib/jar/jasperreports-5.5.0/lib/\*.jar"].each { |jar| require jar }

require "#{Rails.root}/lib/datasource/ticket_data_source.rb"

class Ticket < ActiveRecord::Base
  
  IVA = 10
  
  belongs_to :movie_function
  belongs_to :transaction
  
  def movie
    movie_function.movie
  end
  
  def tax
    if price.nil?
      tax = ((price / 100) * IVA)
    else
      0
    end
  end
  
  def total
    total = price + tax
  end
  
  def print printer_service_name
    start = Time.now
    
    begin
      report = nil
      if Config::Printer.always_recompile_reports?
        report = Java::NetSfJasperreportsEngine::JasperCompileManager.compile_report("#{Rails.root}/app/reports/ticket.jrxml")
      else
        report = Java::NetSfJasperreportsEngineUtil::JRLoader.loadObject("#{Rails.root}/app/reports/ticket.jasper")
      end
      parameters = Java::JavaUtil::HashMap.new
      data_source = TicketDataSource.new self
      print = Java::NetSfJasperreportsEngine::JasperFillManager.fillReport(report, parameters, data_source);
      job = Java::JavaAwtPrint::PrinterJob.printer_job
      services = Java::JavaxPrint::PrintServiceLookup.lookup_print_services nil, nil
      selected_service = 0
      services.to_a.each_with_index do |service, index|
        if service.name.eql? printer_service_name
      		selected_service = index
      	end
      end
      job.print_service = services[selected_service]
      printRequestAttributeSet = Java::JavaxPrintAttribute::HashPrintRequestAttributeSet.new
      printRequestAttributeSet.add( Java::JavaxPrintAttributeStandard::Copies.new(1) )
      exporter = Java::NetSfJasperreportsEngineExport::JRPrintServiceExporter.new
      exporter.setParameter(Java::NetSfJasperreportsEngine::JRExporterParameter::JASPER_PRINT, print)
      exporter.setParameter(Java::NetSfJasperreportsEngineExport::JRPrintServiceExporterParameter::PRINT_SERVICE, services[selected_service])
      exporter.setParameter(Java::NetSfJasperreportsEngineExport::JRPrintServiceExporterParameter::PRINT_SERVICE_ATTRIBUTE_SET, services[selected_service].getAttributes())
      exporter.setParameter(Java::NetSfJasperreportsEngineExport::JRPrintServiceExporterParameter::PRINT_REQUEST_ATTRIBUTE_SET, printRequestAttributeSet)
      exporter.setParameter(Java::NetSfJasperreportsEngineExport::JRPrintServiceExporterParameter::DISPLAY_PAGE_DIALOG, false)
      exporter.setParameter(Java::NetSfJasperreportsEngineExport::JRPrintServiceExporterParameter::DISPLAY_PRINT_DIALOG,	false)
      exporter.exportReport

      msecs = time_diff_milli start, Time.now
      puts 'finished in ' + msecs.to_s
      return true
    
    rescue Exception => ex
      Rails.logger.error ex
      return false
    end
  end
  
  def time_diff_milli(start, finish)
     (finish - start) * 1000.0
  end
  
end

ticket_data_source.rb

import 'net.sf.jasperreports.engine.JRField'
import 'net.sf.jasperreports.engine.JRDataSource'

class TicketDataSource

  java_implements 'net.sf.jasperreports.engine.JRDataSource'
  java_signature 'java.lang.Object getFieldValue(JRField jrField)'
  java_signature 'boolean next()'

  def initialize ticket
    @list = [ticket]
    @index = -1
  end

  def get_field_value jr_field
    
    case jr_field.name
    when 'created_at'     then return @list[@index].created_at.strftime("%d/%m/%y %H:%M")
    when "movie"          then return @list[@index].movie
    when "movie_function" then return @list[@index].movie_function.id
    when "price"          then return @list[@index].price
    when "transaction"    then return @list[@index].transaction.id.to_s + "-T" + @list[@index].id.to_s
    when "payment_method" then return @list[@index].transaction
    when "authorization"  then return ""
    when "cashier"        then return @list[@index].transaction.user
    when "cash_register"  then return @list[@index].transaction.cash_register.id
    when "seat"           then return @list[@index].seat
    else                       return 'empty'
    end
  end
  
  def next?
    @index = @index + 1
    return @index < @list.size
  end
  
end