Extensible Runtime Containment and Services Protocol for JavaBeans: - - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

Extensible Runtime Containment and Services Protocol for JavaBeans

1.0 Introduction.

Currently the JavaBeans specification (Version 1.0) contains neither conventions describing a hierarchy or logical structure of JavaBeans, nor conventions for those JavaBeans to rendezvous with, or obtain arbitrary services or facilities from, the execution environment within which the JavaBean was instantiated.
It is desirable to both provide a logical, traversable, hierarchy of JavaBeans, and further to provide a general mechanism whereby an object instantiating an arbitrary JavaBean can offer that JavaBean a variety of services, or interpose itself between the underlying system service and the JavaBean, in a conventional fashion.
In other component models there exists the concept of a relationship between a Component and its environment, or Container, wherein a newly instantiated Component is provided with a reference to its Container or Embedding Context.
The Container, or Embedding Context not only establishes the hierarchy or logical structure, but its also acts as a service provider that Components may interrogate in order to determine, and subsequently employ, the services provided by their Context.
This proposal defines such a protocol that supports extensible mechanisms that:

Introduce an abstraction for the environment, or context, in which a JavaBean logically functions during its lifecycle, that is a hierarchy or structure of JavaBeans.
Enable the dynamic addition of arbitrary services to a JavaBean's environment.
Provide a single service discovery mechanism through which JavaBeans may interrogate their environment in order both to ascertain the availability of particular services and to subsequently employ those services.
Provide a simple mechanism to propagate an Environment to a JavaBean.
Provide better support for JavaBeans that are also Applets.

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