Delegates: Difference between revisions

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@@ Line 297: / Line 297: @@
 =={{header|Python}}==
+<python>class Delegator:
-<pre>
+   def __init__(self):
-class Delegator:
-    def __init__(self):
+      self.delegate = None
-        self.delegate = None
+   def operation(self):
-    def operation(self):
+       if hasattr(self.delegate, 'thing'):
-         if hasattr(self.delegate, 'thing'):
+          return self.delegate.thing()
+       return 'default implementation'
-             return self.delegate.thing()
-         return 'default implementation'
 class Delegate:
-    def thing(self):
+   def thing(self):
-        return 'delegate implementation'
+      return 'delegate implementation'
 if __name__ == '__main__':
-    # No delegate
+   # No delegate
-    a = Delegator()
+   a = Delegator()
-    assert a.operation() == 'default implementation'
+   assert a.operation() == 'default implementation'
-    # With a delegate that does not implement "thing"
+   # With a delegate that does not implement "thing"
-    a.delegate = 'A delegate may be any object'
+   a.delegate = 'A delegate may be any object'
-    assert a.operation() == 'default implementation'
+   assert a.operation() == 'default implementation'
-    # With delegate that implements "thing"
+   # With delegate that implements "thing"
-    a.delegate = Delegate()
+   a.delegate = Delegate()
-    assert a.operation() == 'delegate implementation'
+   assert a.operation() == 'delegate implementation'</python>
-</pre>