Resource Lifecycle Manager

The Resource Lifecycle Manager pattern decouples the management of the lifecycle of resources from their use by introducing a separate Resource Lifecycle Manager, whose sole responsibility is to manage and maintain the resources of an application. Note: This pattern appeared in a heavily reworked and updated version in the book Pattern-Oriented Software Architecture — Patterns for Resource Management published by Wiley [POSA3]. Example Building distributed systems is challenging. Making distributed systems robust and scalable is even more challenging. The most important aspect of making distributed systems robust and scalable is how resources are managed. Resources in distributed systems can be of many different types, such as network connections, threads, synchronization primitives, servants etc. Network connections represent communication channels between client applications and distributed application services. Managing them efficiently requires the ability to determine when to establish connections and when to release them. Threads are especially important in distributed systems since they provide asynchronous behavior between different parts of an application, for example decoupling UI interaction from typical client functionality and service provisioning. However, managing threads effectively can be quite challenging since it involves close monitoring of their execution and the ability to determine when to create new threads or destroy no longer needed threads. Similarly, synchronization primitives such as locks and tokens are typically needed to synchronize the asynchronous parts of an application and to allow for their internal coordination and interaction. However, when and how these