Design pattern singlestone
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The document discusses implementing a singleton pattern to restrict database connections to a single instance. It explains that the singleton pattern ensures only one instance of a class exists in memory by making the constructor private and providing a static method to access the sole instance. This allows controlling access to and instantiation of the database connection class to enforce only one connection.
Design pattern singlestone
- 3. I have a problem with my system design, I want restrict the instantiation of the database connection to one instance only I want to prevent clients to create more than one database connection. ( Restrict Instances )
- 4. Heap getDBInstance() openConnection() openConnection() openConnection() Thread Thread Thread Stack
- 5. What is singleton pattern ? • A class has only one instance in memory • Initialization only will be at first use • Provide a global point or single point to access the class • Clients cannot create a new instance directly with new keyword • This type of design pattern comes under creational patter
- 6. Singleton Pattern Implementation • Ensure that Class constructor is private to prevent create new instance directly • Define a private static attribute in class to instantiates an only instance at first time • Define static method that returns the instance of the class • Clients may only use the Accessor function to manipulate the Singleton