我看BPEL4People
近来比较关注BPEL4People。这是IBM和SAP提出的一个white paper，目标是给BPEL加上human workflow的功能。一共不到20页，很短很好读。
我觉得BPEL human workflow还是很必要的。在工作流的角度来看，BPEL太像一个编程语言，只是做了service composition，却没有考虑task list等问题；毕竟，多数工作流是要牵涉到人的，比如任何一个公文流转的流程。事实上大多数BPEL厂商都自行扩展了human workflow的支持。引述Bruce Silver的一段话：
The world of BPMS is divided into BPEL-lovers and BPEL-haters, and the thing that BPEL-haters seem to hate most is that even the not-yet-final 2.0 version of the OASIS standard "excludes" human tasks. How can you have a "business process" execution language that cannot accommodate human-performed activities? "Out of scope"?! Are you kidding?
不过，这份white paper迄今还没有变成一份规范；而且有些人批评说它多余，比如这篇Do We Need This Animal Called 'BPEL4People'?，这标题起的几乎有点刻薄了。Bruce Silver在他的文章中也表示BPEL4People有点“overly ambitious”，因为其中提出的5个interaction patterns的构想不太容易实现。
不管怎样，扩展BPEL使之支持human workflow的基本想法还是很好的，这一点Bruce Silver也同意。只是从具体的技术细节来看，BPEL4People可能还有一些不尽人意之处。上个月OASIS的BPEL Webinar上有人提问“BPEL4People什么时候出规范？“回答是”快了“。
6月1日的更新：
仿佛是回应我这篇blog一样
，ActiveBPEL昨天推出了ActiveBPEL for People，支持BPEL4People的大部分功能：
Key capabilities of ActiveBPEL for People include:
-- Extensions to ActiveBPEL Designer, the SOA community's leading BPELauthoring environment, that support the design, testing and deploymentof human-centric BPEL processes
-- New human interaction operations that are wrapped in Web services andinvoked as BPEL activities
-- Task Editor and Task Inbox controls that can be directly embedded intoSOA applications or used as templates for creating custom userinterfaces
-- An ActiveBPEL Task Services subsystem that creates and manages thecomplete lifecycle of human tasks
-- Alarm, escalation and notification services that allow human-centric
applications to be easily integrated with enterprise monitoring and
management infrastructures
-- An identity services infrastructure that integrates with popular enterprise directories to support roles and rights configurations - such as owners, users and administrators - of human tasks
-- Supports common workflow patterns:
-- Four eyes
-- Nomination
