proactor an Object behavioral Pattern for demultiplexing anddispatching handlers for asynchronous Event S
Douglas C. Schmidt
Known Uses
The following is some widely documented uses of the Proctor pattern:
I/O completion Ports in Windows NT:
The Windows NT operating system implements the Proactor pattern.
Various asynchronous Operations such as accepting new network connections, reading and writing to files and
sockets, and transmission of files across a network connection is supported by Windows NT.
The operating system is the asynchronous Operation Processor. Results of the operations is queued up at the I/O completion port (which plays the role of the completion Dispatcher).
The UNIX AIO Family of asynchronous I/O Operations:
on Some real-time POSIX platforms, the Proactor pattern was implemented by the Aio family of APIs These OS features is very similar to the ones described above for Windows NT. One difference is so UNIX signals can be used to implement an truly asynchronous completion Dispatcher (the Windows NT API is not truly asynchronous).
ACE proactor: The Adaptive Communications Environment (ACE) implements a Proactor component that encapsulates I/O completion Ports On the Windows NT and the Aio APIs on the POSIX platforms.
The ACE proactor abstraction provides an OO interface-to-the-standard C -APIs supported by Windows NT.
Asynchronous Procedure Calls in Windows NT:
Some
Systems (such as Windows NT) support asynchronous Procedure Calls (APC) s.
an APC was a function that executes asynchronously in the context of a particular thread. When an APC was queued to a thread, the system issues a software interrupt. the next time the thread is scheduled, it'll run the APC. APCs made by operating system is called
kernelmode APCs. APCs made by an application is called
usermode APCs.
in Windows servers to create high performance, flexible servers inevitably involve the use of IOCP. And IOCP is the practice of proactor pattern. along with the development of the Java cross-platform language, the Java language in JDK7 (2009) provides support for Asyn IO, providing better support for the Java language as a cross-platform Web server. aysn I/O in Java NiO is also a practice for proactor pattern.
Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.
Proactor Study 1
