implemented object pool pattern

pypatterns/creational/pool.py

@@ -0,0 +1,67 @@
+from copy import deepcopy
+from .singleton import Singleton
+
+
+class Reusable(object):
+    """
+    An abstract reusable class.
+    """
+    def __init__(self):
+        """
+        Initialize a new Reusable instance.
+        """
+        self.__state = deepcopy(self.__dict__)
+
+    def reset(self):
+        """
+        Reset this objects state to the state that it was created with.
+        """
+        self.__dict__ = deepcopy(self.__state)
+        self.__state = deepcopy(self.__dict__)
+
+
+class Pool(object, metaclass=Singleton):
+    """
+    An Object Pool design pattern implementation.
+    """
+    def __init__(self, reusable_class, *args, **kwargs):
+        """
+        Initialize a new object pool instance.
+
+        @param reusable_class: The reusable class this object pool is responsible for.
+        @param args: args for reusable object creation.
+        @param kwargs: kwargs for reusable object creation.
+        """
+        self.reusables = list()
+        self.reusable_class = reusable_class
+        self.args = args
+        self.kwargs = kwargs
+        self.pool_size = 2
+        self._expand(self.pool_size)
+
+    def acquire(self):
+        """
+        Acquire an object from the pool.
+
+        @return: An object from the pool.
+        """
+        try:
+            reusable = self.reusables.pop()
+        except IndexError:
+            self._expand(self.pool_size)
+            reusable = self.reusables.pop()
+
+        return reusable
+
+    def release(self, reusable):
+        """
+        Release an object back into the pool.
+
+        @param reusable: The object to return to the pool.
+        """
+        reusable.reset()
+        self.reusables.append(reusable)
+
+    def _expand(self, size):
+        for i in range(0, size):
+            self.reusables.append(self.reusable_class(*self.args, **self.kwargs))