Flyweight

Use sharing to support large numbers of fine-grained objects efficiently.

Applicability

• 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

Consequences

• Reduces the number of instances
• Most of the state must be extrinsic