文章作者:Tyan 博客:noahsnail.com
服务提供者框架英文为Service Provider Framework,主要是指:多个服务提供者实现一个服务,系统为客户端提供多个实现,并把他们从多个实现中解耦出来。服务提供者的改变对它们的客户端是透明的,这样提供了更好的可扩展性。例如,JDBC,JMS等就是用了服务提供者框架。
服务提供者框架主要有四个组件:
Service Interface:
// Service interface
public interface Service {
... // Service-specific methods go here
}
Provider Registration API 和 Service Access API:
// Noninstantiable class for service registration and access
public class Services {
private Services() { } // Prevents instantiation (Item 4)
// Maps service names to services
private static final Map<String, Provider> providers =
new ConcurrentHashMap<String, Provider>();
public static final String DEFAULT_PROVIDER_NAME = "<def>";
// Provider registration API
public static void registerDefaultProvider(Provider p) {
registerProvider(DEFAULT_PROVIDER_NAME, p);
}
public static void registerProvider(String name, Provider p){
providers.put(name, p);
}
// Service access API
public static Service newInstance() {
return newInstance(DEFAULT_PROVIDER_NAME);
}
public static Service newInstance(String name) {
Provider p = providers.get(name);
if (p == null)
throw new IllegalArgumentException(
"No provider registered with name: " + name);
return p.newService();
}
}
Service Provider Interface:
// Service provider interface
public interface Provider {
Service newService();
}
参考资料:
1、http://blog.csdn.net/zl3450341/article/details/7227197
2、http://liwenshui322.iteye.com/blog/1267202
3、Effective Java 2.0