Object Pool

What is Object Pool design pattern?

• Object pool pattern is a software creational design pattern which is used in situations where the cost of initializing a class instance is very high.
• Basically, an Object pool is a container which contains some amount of objects. So, when an object is taken from the pool, it is not available in the pool until it is put back.
• Objects in the pool have a lifecycle:
  1. Creation
  2. Validation
  3. Destroy

UML Diagram

Participants

• Client
  This is the class that uses an object of the PooledObject type.

• ReuseablePool
  The PooledObject class is the type that is expensive or slow to instantiate, or that has limited availability, so is to be held in the object pool.

• ObjectPool
  The Pool class is the most important class in the object pool design pattern. ObjectPool maintains a list of available objects and a collection of objects that have already been requested from the pool.

Advantages

• It offers a significant performance boost.
• It manages the connections and provides a way to reuse and share them.
• Object pool pattern is used when the rate of initializing an instance of the class is high.

When to use Object Pool design pattern

• When we have a work to allocates or deallocates many objects
• Also, when we know that we have a limited number of objects that will be in memory at the same time.

References

• https://sourcemaking.com/design_patterns/object_pool