Added JRuby wrapper for fun scripting times.

git-svn-id: https://zxing.googlecode.com/svn/trunk@1241 59b500cc-1b3d-0410-9834-0bbf25fbcc57

jruby/README.textile

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+h2. Decode QR Codes
+
+p. "QR code":http://en.wikipedia.org/wiki/QR_Code generation is well served in the Ruby community, but decoding seems to be stuck in the Java world. This is an attempt to bridge the gap by wrapping the "ZXing":http://code.google.com/p/zxing/ library with JRuby. ZXing conveniently decodes a plethora of barcodes. Their site has a complete list.
+
+h2. Requirements
+
+    * JRuby (tested with 1.4.0)
+    * shoulda (for testing)
+
+h2. Using the ZXing module/singleton.
+
+<pre>
+  <code>
+    require 'zxing'
+
+    # You can decode a URL...
+    ZXing.decode 'http://2d-code.co.uk/images/bbc-logo-in-qr-code.gif'
+
+    # ... or a file path...
+    ZXing.decode '/Users/ecin/qrcode.png'
+
+    # ... or a File object...
+    ZXing.decode File.open('qrcode.png')
+
+    # ... or anything that returns a URL or file path when #path or #to_s 
+    # is called on it.
+    class Image
+      attr_reader :path
+      def initialize(path); @path = path end
+    end
+
+    image = Image.new('qrcode.png')
+    ZXing.decode image
+      
+    # #decode returns nil if it can't decode the image.
+    ZXing.decode 'image_without_a_code.png'
+    # => nil
+
+    # #decode! will raise an error if it can't decode the image.
+    ZXing.decode! 'image_without_a_code.png'
+    # => NativeException
+
+    # Feel free to include ZXing to shorten the call.
+    include ZXing
+
+    decode 'qrcode.png'
+  </code>
+</pre>
+
+h2. Including the Decodable module.
+
+p. A Decodable module is included (pun intended) to ease using the library with objects that return the URL or file path to decode when #path or #to_s is called.
+
+<pre>
+  <code>
+     require 'zxing/decodable'
+
+     class File
+       include Decodable
+     end
+
+     file = File.open('qrcode.png')
+     file.decode
+   </code>
+</pre>

jruby/lib/zxing.rb

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+raise "ZXing requires JRuby" unless defined?(JRuby)
+
+require File.expand_path( File.dirname(__FILE__) + '/core.jar' )	  # ZXing core classes
+require File.expand_path( File.dirname(__FILE__) + '/javase.jar' )	# ZXing JavaSE classes
+
+require 'uri'
+
+# Google ZXing classes
+java_import com.google.zxing.MultiFormatReader
+java_import com.google.zxing.BinaryBitmap
+java_import com.google.zxing.Binarizer
+java_import com.google.zxing.common.GlobalHistogramBinarizer
+java_import com.google.zxing.LuminanceSource
+java_import com.google.zxing.client.j2se.BufferedImageLuminanceSource
+
+# Standard Java classes
+java_import javax.imageio.ImageIO
+java_import java.net.URL
+
+module ZXing
+
+  @@decoder = MultiFormatReader.new
+
+  # Transform the module into a singleton!
+  extend self
+
+  def decode(descriptor)
+    begin
+      decode!(descriptor)
+    rescue NativeException
+      return nil
+    end
+  end
+
+  def decode!(descriptor)
+    descriptor = descriptor.path if descriptor.respond_to? :path
+    descriptor = descriptor.to_s
+    descriptor = case descriptor
+    when URI.regexp(['http', 'https'])
+      URL.new(descriptor)
+    else
+      Java::JavaIO::File.new(descriptor)
+    end
+    image = ImageIO.read(descriptor)
+    bitmap = to_bitmap(image)
+    @@decoder.decode(bitmap).to_s
+  end
+
+  private
+
+  def to_bitmap(image)
+    luminance = BufferedImageLuminanceSource.new(image)
+    binarizer = GlobalHistogramBinarizer.new(luminance)
+    BinaryBitmap.new(binarizer)
+  end
+end

jruby/lib/zxing/decodable.rb

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+require File.expand_path( File.dirname(__FILE__) + '/../zxing')
+
+module Decodable
+  def decode
+    ZXing.decode(self)
+  end
+
+  def decode!
+    ZXing.decode!(self)
+  end
+end

jruby/test/test_helper.rb

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+$LOAD_PATH.unshift File.expand_path( File.dirname(__FILE__) + '/../lib')
+$LOAD_PATH.unshift File.expand_path( File.dirname(__FILE__) )
+
+require 'shoulda'

jruby/test/zxing/decodable_test.rb

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+#!/usr/bin/env jruby --headless -rubygems
+
+require File.expand_path( File.dirname(__FILE__) + '/../test_helper')
+require 'zxing/decodable'
+
+class DecodableTest < Test::Unit::TestCase
+
+  class Object::File
+    include Decodable
+  end
+
+  class URL
+    include Decodable
+    def initialize(path)
+      @path = path
+    end
+    def path; @path end
+  end
+
+  context "A Decodable module" do
+    setup do
+      @file = File.open( File.expand_path( File.dirname(__FILE__) + '/../qrcode.png' ))
+      @uri = URL.new "http://2d-code.co.uk/images/bbc-logo-in-qr-code.gif"
+      @bad_uri = URL.new "http://google.com"
+    end
+
+    should "provide #decode to decode the return value of #path" do
+      assert_equal @file.decode, ZXing.decode(@file.path)
+      assert_equal @uri.decode, ZXing.decode(@uri.path)
+      assert_nil @bad_uri.decode
+    end
+
+    should "provide #decode! as well" do
+      assert_equal @file.decode!, ZXing.decode(@file.path)
+      assert_equal @uri.decode!, ZXing.decode(@uri.path)
+      assert_raise(NativeException) { @bad_uri.decode! }
+    end
+  end
+
+end

jruby/test/zxing_test.rb

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+#!/usr/bin/env jruby --headless -rubygems
+
+require File.expand_path( File.dirname(__FILE__) + '/test_helper')
+require 'zxing'
+
+class ZXingTest < Test::Unit::TestCase
+  context "A QR decoder singleton" do
+
+    class Foo < Struct.new(:v); def to_s; self.v; end; end
+
+    setup do
+      @decoder = ZXing
+      @uri = "http://2d-code.co.uk/images/bbc-logo-in-qr-code.gif"
+      @path = File.expand_path( File.dirname(__FILE__) + '/qrcode.png')
+      @file = File.new(@path)
+      @google_logo = "http://www.google.com/logos/grandparentsday10.gif"
+      @uri_result = "http://bbc.co.uk/programmes"
+      @path_result = "http://rubyflow.com"
+    end
+
+    should "decode a URL" do
+      assert_equal @decoder.decode(@uri), @uri_result
+    end
+
+    should "decode a file path" do
+      assert_equal @decoder.decode(@path), @path_result
+    end
+
+    should "return nil if #decode fails" do
+      assert_nil @decoder.decode(@google_logo)
+    end
+
+    should "raise an exception if #decode! fails" do
+      assert_raise(NativeException) { @decoder.decode!(@google_logo) }
+    end
+
+    should "decode objects that respond to #path" do
+      assert_equal @decoder.decode(@file), @path_result
+    end
+
+    should "call #to_s to argument passed in as a last resort" do
+      assert_equal @decoder.decode(Foo.new(@path)), @path_result
+    end
+  end
+
+  context "A QR decoder module" do
+    
+    setup do
+      class SpyRing; include ZXing end
+      @ring = SpyRing.new
+    end
+
+    should "include #decode and #decode! into classes" do
+      assert_equal defined?(@ring.decode), "method"
+      assert_equal defined?(@ring.decode!), "method"
+    end
+
+  end
+end