J2EE Pattern

Service Locator Pattern

Creational patterns Structural patterns Behavioral pattern J2EE patterns Abstract Factory Adapter  Chain of Responsibility MVC  Builder Bridge  Command  Business Delegate Factory method Composite  Interpreter  Composite Entity Prototype Decorator  Iterator  Data Access Object Singleton Façade Mediator  Front Controller Flyweight  Memento  Intercepting Filter Proxy  Observer  Service Locator State  Transfer Object Strategy  Template Method Visitor

Service Locator

Define Service Locator

Centralizing distributed service object lookups, providing a centralized point of control, acting as a cache that eliminates redundant lookups.

Where to use & benefits

Lookup object in JNDI, RMI, JMS, etc. Encapsulate any vendor-specific features of lookup process Simplify the lookup process Improve the performance Related patterns include Singlton combined with service locator to make sure only one lookup object exists.

Example Service Locator

Use a container as cache to hold the lookup object. One application only lookups same object once. Doing so will dramatically improve performance. Make sure the container used is thread-safe.