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flyweight/README.md

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+## Flyweight
+
+Use sharing to support large numbers of fine-grained objects efficiently. 
+
+### When to use
+
+* when all of the following are true
+ * an application uses a large number of objects
+ * storage costs are high because of the sheer quantity of objects
+ * most object state can be made extrinsic
+ * many groups of objects may be replaced by relatively few shared objects once extrinsic state is removed
+ * the application doesn't depend on object identity