Constructing a WebServers with Patterns

一、Case Study  -  A High-Performance Web Server
1. Event Demutiplexing
    Reactor
       
2. Connection Establishment
    Acceptor-Connector

3. Concurrency
    Leader/Followers

4. Concurrency Coordination
    Monitor

5. Efficient Content Access
    Cache
        One Cache Only
        Cache Management
        Evictor
        Flexible Cache Management  ->  strategies

6. Reliable Synchronization
    Scoped Locking

7. Efficient Synchronization
    Strategized Locking   ->  template
    Double-Checked Locking

8. Accessing OS APIs
    Wrapper Facade

Patterns helped us realizing a highly efficient yet flexible web server:
1) Reactor defines the fundamental event handling architecture of the web server.
2) Acceptor-Connector improves availability by separating connection establishment from HTTP processing
3) Leader/Followers and Monitor Object provide a high-performance concurrency architecture.
4) Caching and an Evictor with associated eviction Strategies speed up accessing frequently used URLs.
5) Singleton ensures the uniqueness of the server's virtual file system.
6) Scoped Locking, Strategized Locking, and Double-Checked Locking ensure that the virtual file system is thread-safe without incurring locking overhead.
7) Wrapper Facade ensures portability.

二、Further Refinements
1. Abstractions
2. Layers
3. Out-of-the-Band Functionality
4. Interceptor
5. Runtime Configuration
    Component Cnofigurator