Softw Syst Model (2003) 2: 37–58 / Digital Object Identifier (DOI) 10.1007/s10270-003-0018-x

Dealing with forward and backward jumps

E-mail: {reichert,dadam}@informatik.uni-ulm.de

ADEPT project, therefore, we have developed advanced

unforeseen events. In this paper, we focus on forward and

limitations arising in this context. Our experiences with

pressure companies must face [4]. To meet this chal-

(workflow; abbr. WF) that can pass through an elec-

logic is extracted from application code. So, instead of

hensive process support as well. In many domains, like

hospitals, engineering environments, or E-Commerce,

Instead users must be able to flexibly deviate from the

standard process (e.g., by skipping WF activities or by

person. As reported by several groups, insufficient flexi-

bility and adaptability have been primary reasons why

many WfMS failed in process automation projects in the

past [17, 19, 41].

can be pre-planned and deviations for which this is not

possible. Concerning pre-planned deviations, their con-

which aims at the flexible support of enterprise-wide busi-

mented advanced concepts for the modeling, execution,

on first-hand knowledge with clinical as well as engineer-

level [41].

the increase of flexibility at buildtime and its enhance-

ment during runtime. Thereby, we focus on the support of

some respects forward and backward jumps bear resem-

CONTROL_E denotes “normal” order relations between ac-

of parallel branches, and LOOP_E loop backs. Similarly,

each node n∈Nhas a node type NT(n)∈NodeTypes

STARTLOOP,ENDLOOP,AND Split,XOR Split,AND Join,

XOR Join}). Based on these ingredients, sequences, paral-

ings (AND/XOR split,XOR join), and loops (STARTLOOP,

ENDLOOP) can be easily modeled. For this we have adopted

We have selected this block structure because it is rather

quickly understood by users, it allows the provision of

user-friendly, syntax-driven model editors, and it makes it

possible to implement efficient algorithms for control and

decessor and successor functions on WF graphs which are

needed for the following considerations.

WF instances created from the WF schema from Fig. 1.

ing the absence of deadlocks, the proper termination of

NOT_ACTIVATED. It is changed to ACTIVATED when all pre-

corresponding work items are inserted into the worklists

of authorized users (determined by role-based work as-

put parameter is mapped to exactly one data element

by a read data edge and each activity output parame-

ter is connected to a data element by a write data edge.

An example is depicted in Fig. 1. Activity “order med-

most important one ensures that all data elements read

signed to it at buildtime; otherwise the setting REGULAR

will be chosen as priority for this activity (default set-

priorities, or the display of the work items related to

these activities within different windows. Combined with

AND-split/XOR-join branchings – called AND-/XOR-

very useful: When the AND-split node of such a branch-

A simple example is given in Fig. 5. In the depicted WF

Due to the assigned priorities Bis offered as regular step

in user worklists whereas Xis treated as exceptional ac-

3.2.2 Pre-planned changes of activity priorities

Depending on the state of a WF instance it must be pos-

ecution of Xconstitutes a deviation from the preferred

this exceptional state must be preserved as long as not all

able to capture such priority changes in the WF model we

order between them. Each prioritization edge epis associ-

which has the following semantics: When the source node

As an example take an activity Ywith (static) priority

stance graph depicted in Fig. 6a, activities Cand Dare

concurrently active whereas Cis treated as normal step

cordingtothis,priorityofactivityDis changed from

EXCEPTIONAL to REGULAR such that Dcan be offered as

planned jumps can be defined at a high semantic level.