Tim Hall - Assignment 7

assignments/assignment08.rb

@@ -1,72 +1,120 @@
 # ========================================================================================
-# Assignment 8
+# Assignment 7
 # ========================================================================================
 
 # ========================================================================================
-#  Problem 1 - Roman Numerals
+#  Problem 1 - Observable
 
-# implement conversion between integers and roman numerals
+# implement Observable
 # validate using MiniTest unit tests
 
-module Assignment08
-  class RomanNumeral
-    def initialize(i)
-      # your implementation here
+module Assignment07
+  module Observable
+    def add_observer(obj)
+      if defined? @observers
+        @observers << obj
+      else
+        @observers = [obj]
+      end
     end
-
-    def to_s
-      # your implementation here
+    def delete_observer(obj)
+      if defined? @observers
+        @observers.delete obj
+      end
     end
-
-    def to_i
-      # your implementation here
+    def delete_observers
+      if defined? @observers
+        @observers = []
+      end
+    end
+    def changed(new_state=true)
+      @state = new_state
     end
-
-    # bonus: create from Roman Numeral
-    def self.from_string
-      # your implementation here
-      # returns a new instance
+    def changed?
+      if @state.nil?
+        @state = false
+      else
+      @state
+    end
+
+    # if changed state is true, invoke the update method in each associated observer. then changed state becomes false.
+    def notify_observers(*args)   #splat operator - multipel comma-separated params at end
+      if @state == true
+        @observers.each do |observer| 
+          observer.send ("update", args)
+        end
+      end
+        @state = false
+      end
     end
   end
 end
 
-# expected results:
-RomanNumeral.new(1).to_s   # => 'I'
-RomanNumeral.new(2).to_s   # => 'II'
-RomanNumeral.new(3).to_s   # => 'III'
-RomanNumeral.new(4).to_s   # => 'IV'
-RomanNumeral.new(5).to_s   # => 'V'
-RomanNumeral.new(6).to_s   # => 'VI'
-RomanNumeral.new(9).to_s   # => 'IX'
-RomanNumeral.new(10).to_s  # => 'X'
-RomanNumeral.new(19).to_s  # => 'XIX'
-RomanNumeral.new(32).to_s  # => 'XXXII'
-RomanNumeral.new(51).to_s  # => 'LI'
 
-# bonus:
-RomanNumeral.from_string('III').to_i  # => 3
-RomanNumeral.from_string('IX').to_i   # => 9
-RomanNumeral.from_string('IX').to_i   # => 9
+require 'minitest/autorun'
 
-# given any arbitrary integer n:
-n == RomanNumeral.from_string(RomanNumeral.new(n).to_s).to_i
+class TestObservable < MiniTest::Test
+
+  class Thermometer
+    include Assignment07::Observable
+    def initialize(temp)
+      @temp = temp
+    end
 
+    def up
+      @temp += 1
+      notify_observers @temp
+    end
 
+    def down
+      @temp -= 1
+      notify_observers @temp
+    end
+  end
 
-# ========================================================================================
-#  Problem 2: Golden Ratio
+  class ThermometerControl
+    def initialize(thermometer)
+      @thermometer = thermometer
+    end
 
-# Golden Ratio is ratio between consecutive Fibonacci numbers
-# calculate the golden ratio up to specified precision
-# validate using MiniTest unit tests
+    def click_up
+      @thermometer.up
+    end
 
-module Assignment08
-  def golden_ratio(precision)
-    # your implementation here
+    def click_down
+      @thermometer.docn
+    end
+  end
+
+  class ThermometerDisplay
+    def initialize(thermometer)
+      thermometer.add_observer self
+    end
+
+    def render(temp)
+      puts temp
+    end
+
+    def update(temp)
+      render temp
+    end
   end
-end
 
-# expected results:
-golden_ratio(2)  # => 1.62
-golden_ratio(5)  # => 1.61803
-golden_ratio(8)  # => 1.61803399
+  def test_observable
+    t = Thermometer.new 68
+    tc = ThermometerControl.new t
+    td = ThermometerDisplay.new t
+    tc.click_up
+    assert_equal 69, td.render
+    tc.click_down
+    assert_equal 68, td.render
+    t2 = Thermometer.new 5
+    tc2 = ThermometerControl.new t2
+    td2 = ThermometerDisplay.new t2
+    tc2.click_up
+    assert_equal 6, td2.render
+    tc2.clicp_down
+    assert_equal 5, td2.render
+  end
+
+end