In addition, I decided to play with the addValue method and see what I
could come up with besides raw arrays (which is actually probably the
best way of loading raw datasets) if you were handcoding a graph.

I would be fun if we could get some threads going on list to discuss
good rubification of Java API techniques…

-Tom

—– jfree.rb —-
include Java

import org.jfree.data.category.DefaultCategoryDataset

class DefaultCategoryDataset
class Inner
def initialize(dataset, row)
@dataset, @row = dataset, row.to_s
end

# a value of nil can call ‘removeValue’
def []=(column, value)
@dataset.addValue value, @row, column.to_s
end

def populate(hash)
hash.each_with_pair do |column, value|
@dataset.addValue value, @row, column.to_s
end
end
end

def [](row)
Inner.new self, row
end
end

module Graph
class StackedBar
import org.jfree.chart.ChartUtilities
import org.jfree.chart.JFreeChart
import org.jfree.chart.ChartFactory
import org.jfree.chart.plot.PlotOrientation

def initialize(width=600, height=400, dataset=create_sample_data)
@height, @width, @chart = height, width, create_chart(dataset)
end

def render_to_file(filename, format=”png”)
puts “Rendering graph to #{filename}”
javafile = java.io.File.new(filename)
ChartUtilities.saveChartAsPNG(javafile, @chart, @width, @height)
end

private
def create_sample_data
# I thought about method_missing for dataset.submitted but since these
# can be arbitrary strings with method-name unfriendly chars in it I
# decided against it.

# This also allows symbols as well as strings
dataset = DefaultCategoryDataset.new
dataset[:Submitted].populate(:A => 1, :B => 2, :C => 3)
dataset[:Assigned].populate(:A => 1, :C => 1)
dataset["In-work"].populate(:A => 3, :C => 3)
dataset[:InVerfication][:A] = 1
dataset[:Delivered][:A] = 2
dataset[:Rejected][:B] = 1
dataset[:Closed][:B] = 1
dataset["On-hold"][:C] = 2
dataset
end

def create_chart(dataset)
ChartFactory.createStackedBarChart(“XYZ’s Development Projects”,
“Project Name”,
“Hours”,
dataset,
PlotOrientation::VERTICAL,
true,
true,
false)
end
end # class StackedBar
end # class Graph

sb = Graph::StackedBar.new
sb.render_to_file(“stacked_bar.png”)