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Chapter 10
The Resource Service

Michael Adams

10.1 Introduction

A workflow comprises three main perspectives: control-flow, data, and resources.
The resource perspective is particularly important because, for the most part, work-
flow tasks are designed to be performed by people, and so a workflow environment
should support efficient and flexible ways to associate work with the people who
have the required skills and authorizations to carry it out. Thus, the resource per-
spective is primarily responsible for modeling an organizational structure, and the
people who populate it, in a computational form, so that a person may be coupled
with tasks and data emanating from the control-flow and data perspectives.
While control-flow and data-flow are necessarily tightly coupled within a work-
flow enactment engine, in the YAWL environment the resource perspective is
supported by a discrete Custom Service called the Resource Service, in line with
YAWL’s Service Oriented Architecture. Consequently, the Engine is oblivious to the
assignment of resources to tasks (i.e., it is said to be agnostic with regards to resourc-
ing). The YAWL Resource Service provides full support for 37 of the 43 identified
resource patterns (the remaining six being particular to the case-handling paradigm)
and so may be considered the preeminent implementer of workflow resource pattern
support.

10.2 Functional Overview

The YAWL Resource Service is the largest and most complex Custom Service
implemented for the YAWL environment and consists of several distinct compo-
nents. This section gives a broad functional overview of the service, followed by
more detailed discussion of the various components in later sections.

M. Adams
Queensland University of Technology, Brisbane, Australia
e-mail: mj.adams@qut.edu.au

A.H.M. ter Hofstede et al. (eds.), Modern Business Process Automation, 261
DOI 10.1007/978-3-642-03121-2 10, c Springer-Verlag Berlin Heidelberg 2010