Another BPEL remarks
The link is at
http://www.ebpml.org/bpel4ws.htm
Some arguments are quoted here. Words in blue are my own explanation.
1. WSDL foundation for a process definition is not the most natural. In the peer-to-peer interaction scenario, it is rarely that two arbitrary APIs designed in complete isolation could operate in harmony. WSDL originally provides with RPC APIs; but now it is more messaging oriented.
2. Web services model is not general enough to represent any arbitrary data exchange, especially between business partners. BPEL needs to define extra activities to exchange data between business partners.
3. Control Flow
No reference to a process composition and the notion of subprocess. A process instance is created in the activities that receive messages such as receive and pick activities. Instances communicate with each other by global variables.
4.Message Flow
Lack of timeout on an invoke activity.
Receive, reply and invoke activities need a "partner" attribute. This leads a process to be only able to talk with the outside world. A BPEL process can not describe the message exchange between any two internal components. For example, one part of a process may need to call other part. Why a process may consist of two or more components?
5. Data Flow
No transformation on the data. Why not simply allow a
element to do it? BPEL depends on XPATH to manipulate XML data. XLST could be used to accomplish transformation.
6. Transaction Flow
Using UNDO
To be continued...
http://www.ebpml.org/bpel4ws.htm
Some arguments are quoted here. Words in blue are my own explanation.
1. WSDL foundation for a process definition is not the most natural. In the peer-to-peer interaction scenario, it is rarely that two arbitrary APIs designed in complete isolation could operate in harmony. WSDL originally provides with RPC APIs; but now it is more messaging oriented.
2. Web services model is not general enough to represent any arbitrary data exchange, especially between business partners. BPEL needs to define extra activities to exchange data between business partners.
3. Control Flow
No reference to a process composition and the notion of subprocess. A process instance is created in the activities that receive messages such as receive and pick activities. Instances communicate with each other by global variables.
4.Message Flow
Lack of timeout on an invoke activity.
Receive, reply and invoke activities need a "partner" attribute. This leads a process to be only able to talk with the outside world. A BPEL process can not describe the message exchange between any two internal components. For example, one part of a process may need to call other part. Why a process may consist of two or more components?
5. Data Flow
No transformation on the data. Why not simply allow a
element to do it? BPEL depends on XPATH to manipulate XML data. XLST could be used to accomplish transformation.
6. Transaction Flow
Using UNDO
To be continued...
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