Merge pull request #10 from KitaitiMakoto/obsolete

Add Obsolete decorator

lib/method_decorators/deprecated.rb

@@ -0,0 +1,84 @@
+require 'method_decorators'
+
+module MethodDecorators
+  # Example:
+  #   class MyClass
+  #     extend MethodDecorators
+  #
+  #     +MethodDecorators::Deprecated
+  #     def deprecated_method
+  #       brand_new_method
+  #     end
+  #   end
+  # When deprecated_method is called, message
+  #   "MyClass#deprecated_method is deprecated"
+  # is output.
+  #
+  # Another example:
+  #   class MyClass
+  #     extend MethodDecorators
+  #
+  #     +MethodDecorators::Deprecated.new('deprecated_method will be removed in the future')
+  #     def deprecated_method
+  #       brand_new_method
+  #     end
+  #   end
+  # Above output given message
+  #   "deprecated_method will be removed in the future"
+  #
+  # Custom message example:
+  #   class MyClass
+  #     extend MethodDecorators
+  #
+  #     +MethodDecorators::Deprecated.new {|class_name, method_name| "#{class_name}##{method_name} will be removed in the future. Use #{class_name}#brand_new_method instead"}
+  #     def deprecated_method
+  #       brand_new_method
+  #     end
+  #   end
+  # Outputs
+  #   "MyClass#deprecated_method will be removed in the future. Use MyClass#brand_new_method instead"
+  # As you see, you can use class name as the first argument and method name as the second in the block.
+  #
+  # Formatter example:
+  #   class Formatter2
+  #     def call(class_name, method_name)
+  #       "#{class_name}##{method_name} will be removed after the next version. Use #{class_name}#brand_new_method instead"
+  #     end
+  #   end
+  #   class MyClass
+  #     extend MethodDecorators
+  #
+  #     formatter1 = ->(class_mane, method_name) {"#{class_name}##{method_name} will be removed in the next version. Use #{class_name}#brand_new_method instead"}
+  #     +MethodDecorators::Deprecated.new(formatter1)
+  #     def very_old_method
+  #       brand_new_method
+  #     end
+  #
+  #     + MethodDecorators::Deprecated.new(Formatter2.new)
+  #     def deprecated_method
+  #       brand_new_method
+  #     end
+  #   end
+  # Outputs
+  #   "MyClass#deprecated_method will be removed in the future. Use MyClass#brand_new_method instead"
+  # You can give any object which responds to method "call" like Proc.
+  class Deprecated < Decorator
+    DEFAULT_FORMATTER = lambda {|class_name, method_name| "#{class_name}##{method_name} is deprecated"}
+    def initialize(message=nil, &blk)
+      @message = message || blk || DEFAULT_FORMATTER
+    end
+
+    def call(orig, this, *args, &blk)
+      warn message(this.class, orig.name)
+      orig.call(*args, &blk)
+    end
+
+    def message(class_name, method_name)
+      if @message.respond_to? :call
+        @message.call(class_name, method_name)
+      else
+        @message.to_s
+      end
+    end
+  end
+end

spec/decorators/deprecated.rb

@@ -0,0 +1,115 @@
+require 'spec_helper'
+require 'method_decorators/deprecated'
+require 'stringio'
+
+describe MethodDecorators::Deprecated do
+  let(:method) { double(:method, :call => 'return value of original method', :name => 'deprecated_method') }
+
+  describe '#call' do
+    subject { MethodDecorators::Deprecated.new }
+
+    it 'calls original method' do
+      method.should_receive(:call)
+      subject.call(method, nil)
+    end
+
+    it 'warns' do
+      subject.should_receive(:warn)
+      subject.call(method, nil)
+    end
+
+    context 'when string given on initializing' do
+      subject { MethodDecorators::Deprecated.new('custom message') }
+
+      it 'warns with given string' do
+        subject.should_receive(:warn).with('custom message')
+        subject.call(method, nil)
+      end
+    end
+
+    context 'when block given on initializing' do
+      subject { MethodDecorators::Deprecated.new {|klass, method| "#{klass}##{method}"} }
+
+      it 'warns with message formatted by the block' do
+        subject.should_receive(:warn).with('NilClass#deprecated_method')
+        subject.call(method, nil)
+      end
+    end
+
+    context 'when object which has #call method given on initializing' do
+      subject { MethodDecorators::Deprecated.new(lambda { |klass, method| "#{klass}##{method}" }) }
+
+      it 'warns with message formatted by the object' do
+        subject.should_receive(:warn).with('NilClass#deprecated_method')
+        subject.call(method, nil)
+      end
+    end
+  end
+
+  describe 'acceptance' do
+    before do
+      $stderr = StringIO.new
+      subject.deprecated_method
+      $stderr.rewind
+    end
+
+    let(:klass) {
+      Class.new Base do
+        +MethodDecorators::Deprecated
+        def deprecated_method
+          'return value of original method'
+        end
+      end
+    }
+    subject { klass.new }
+
+    it 'warns' do
+      expect($stderr.read).to eq("#{klass}#deprecated_method is deprecated\n")
+    end
+
+    context 'when string given on initializing' do
+      let(:klass) {
+        Class.new Base do
+          +MethodDecorators::Deprecated.new('custom message')
+          def deprecated_method
+            'return value of original method'
+          end
+        end
+      }
+
+      it 'warns with given string' do
+        expect($stderr.read).to eq("custom message\n")
+      end
+    end
+
+    context 'when block given on initializing' do
+      let(:klass) {
+        Class.new Base do
+          +MethodDecorators::Deprecated.new {|class_name, method_name| "#{class_name}##{method_name} is deprecated"}
+          def deprecated_method
+            'return value of original method'
+          end
+        end
+      }
+
+      it 'warns with message formatted by the block' do
+        expect($stderr.read).to eq("#{klass}#deprecated_method is deprecated\n")
+      end
+    end
+
+    context 'when object witch has #call method givn on initializing' do
+      let(:klass) {
+        Class.new Base do
+          +MethodDecorators::Deprecated.new(lambda { |class_name, method_name| "#{class_name}##{method_name} is deprecated" })
+          def deprecated_method
+            'return value of original method'
+          end
+        end
+      }
+
+      it 'warns with message formatted by the object' do
+        expect($stderr.read).to eq("#{klass}#deprecated_method is deprecated\n")
+      end
+    end
+  end
+end