BPEL continued

More on BPEL

flow

set of invocations without the explicit sequencing but with dataflow constraints

why don’t we want to build conditional logic into the components 1

reduces reuse, complicates coding

why don’t we want to build conditional logic into the components 2

might not be true for all uses of the component

notes on links

a link can have an associate traversal condition

why is it important to separate the process logic from the individual partner logic

partners may not know why we can’t proceed and this may be sensitive information that they shouldn’t know

event of failure

need to undo previous work by specifying a handler that runs to undo work in a particular scope

pros of bpel 1

business focused and xml structured

pros of bpel 2

portable

pros of bpel 3

leverages web standards

pros of bpel 4

lets us script components together

cons of bpel 1

not a great computation model

cons of bpel 2

uncomfortable constructions

cons of bpel 3

hard to check correctness

cons of bpel 4

can’t reasonably expect programmers to write decent sized processes without significant tools