=Paper=
{{Paper
|id=Vol-1418/paper25
|storemode=property
|title=The bflow* Hive - Adding Functionality to Eclipse-based Modelling Tools
|pdfUrl=https://ceur-ws.org/Vol-1418/paper25.pdf
|volume=Vol-1418
|dblpUrl=https://dblp.org/rec/conf/bpm/0001SH15
}}
==The bflow* Hive - Adding Functionality to Eclipse-based Modelling Tools==
https://ceur-ws.org/Vol-1418/paper25.pdf
The bflow* Hive – Adding Functionality to
Eclipse-based Modelling Tools
Ralf Laue1 , Arian Storch2 , and Felix Höß3
1
University of Applied Sciences of Zwickau, Department of Information Science
Dr.-Friedrichs-Ring 2a, 08056 Zwickau, Germany
ralf.laue@fh-zwickau.de
2
it factum GmbH
Hainstr. 6, 04109 Leipzig
arian.storch@it-factum.de
3
University of Hamburg, Chair of Information Systems, Germany
Felix.Hoess@studium.uni-hamburg.de
Abstract. The bflow* Hive is a collection of Eclipse plug-ins that can
be integrated into various Eclipse-based modeling tools. It adds several
features that are useful in particular for model analysis and model ex-
change. Most of these features put the principle of end user-programming
into practice: Modeling tool users can add their own add-ons at runtime
without having to re-compile the original modeling tool. We hope that
this will be useful in particular for researchers. They can extend a model-
ing tool with own model analysis features without having to touch the
sources of the modeling tool.
1 Introduction
The bflow* Toolbox [1] is an Eclipse-based open-source tool for graphical business
process modeling using the Event-Driven Process Chains notation. From the
beginning, it was the aim of its developers to make the tool open for contributions.
While this is quite normal for an open-source product, we tried to go one step
further. We provided interfaces to third-party tools such that those tools can be
integrated into our modeling tool without having to become familiar with our
source code or with Eclipse programming. A survey by Hannebauer et al. [2]
showed that a major part of the barrier to contribute to open-source software is
the effort invested until the first build. By lowering this barrier, we hope that
more contributors can be encouraged to add their own extensions to our modeling
tool.
While in the first years, our work concentrated on our own tool, we soon
realized that this idea could be useful for other graphical modeling tools as well.
Therefore we refactored our code which resulted in Eclipse plug-ins that can
Copyright c 2015 for this paper by its authors. Copying permitted for private and
academic purposes
be used with other modelling tools based on Eclipse using EMF and GMF or
Graphiti. As a result, modellers and researchers can add their own extensions to
those tools.
2 Features
2.1 Export / Import
We provide two ways for adding a transformation into or from an external file
format: either by using XSLT or by using a transformation language which is based
on the template language Apache Velocity. A new export/import can be added
by creating a transformation script file, another file defining the transformation
metadata (for instance, name or description) and placing both into a subdirectory
of the modelling tool’s workspace.
2.2 User-Defined Attributes and Icons
For model analysis purposes, it is often desirable to add custom-defined attributes
to model elements (for example information about cost and duration to an activity
or a probability to a control-flow edge). Unfortunately, this is not always supported
by the original modelling tool. We created a new Eclipse view called “Attribute
View” which allows to add arbitrary attributes to model elements. An attribute
can be a numerical or textual value or an URL. In the latter case, the resource
located by the URL can be opened from the Attribute View. This makes it
possible to attach files or web sites with additional information to any node or
vertex in the model. Additionally, a “Filter View” allows to show only those
model elements whose attributes have a certain value (for example all activities
where the attribute “cost” is larger than a given value).
It is possible to define that the shapes of the diagram should be decorated
with icons when the value of a user-defined attribute is within a given range.
For this purpose, the icon graphics and a map from attribute values to icons
to be shown has to be added to a subfolder of the modeling tool. Using this
mechanism, we were able to include the EPC model variant for Risk-aware
Event-Driven Process Chains [3] into the bflow* Toolbox without the need to
change the metamodel. Fig. 1(a) shows the Attribute View integrated into the
BPMN2 Modeler (www.eclipse.org/bpmn2-modeler/); Fig. shows 1(b) an event
in the bflow* Toolbox with a decorating “Risk” icon.
2.3 Model Validation
For improving the model quality, it can be desirable to give the modeller feedback
about possible modelling problems or detected anti-patterns at modelling time.1
For this purpose, we provide a mechanism to define checking rules in three
1
The reader who is interested in this, might alternatively consider to use the EMF
Refactor project, see www.eclipse.org/emf-refactor [4]
(a) User-Defined Attributes added to the BPMN2 (b) Shape with
Modeler Icon
Fig. 1. Adding Attributes and Icons
languages: the Epsilon Validation language (EVL), openArchitectureWare Check
and Prolog. For rules expressed in EVL, it is also possible to define so-called
“Quick-Fixes”, i.e. model transformations that correct a problem.
The bflow* Hive provides the functionality for adding user-defined validation
rules, for selecting the rules that should be applied, for the internationalisation
of problem messages and for changing the problem messages according to the
users’ preferences. Fig. 2 shows how validation rules have been integrated into
openOME, a tool for goal-oriented requirements modelling.
2.4 Add-ons
The framework allows to define “add-ons”. An add-on can be described as a
sequence of steps which defines how to...
1. Extract the model data and translate it into the input format that is required
by an external program.
Fig. 2. Validation in openOME
2. Call the external program or a chain of such programs with specified param-
eters.
3. Read the result data of the program(s).
4. Show the result by changing one or more views in the modeling tool.
For each of those steps, our framework already provides out-of-the-box com-
ponents which just need to be invoked in the right order and with the right
parameters.
Fig. 3 shows possible executions of an add-on. As illustrated, the components
are combined using a pipes-and-filters architecture.
Fig. 3. Components of an Add-on
The called program(s) deliver the result by writing either into a file or to the
standard output stream of the process. To update a view of the model within the
modeling tool, the rightmost component in Fig. 3 a) requires an input in form of
predefined commands. If the external program does not provide the output in
the required format, we have to call another program as an adapter. For showing
the results of the external program(s), it is possible to use components that can
do the following actions:
– Printing information into the Eclipse Console View
– Adding information about an error, warning or information Eclipse’s Problems
View
– Changing the label or the graphical attributes (e.g. size, color, font-style) of
model elements
– Changing the user-defined attributes of model elements (in addition, this can
result in decorating a model element with icons) (as shown in Fig. 1(b))
– Showing a generated HTML page
With the help of the add-on mechanism, extensions in great variety have been
developed. There are add-ons for model-checking, quality-of-service calculation for
business processes, business process simulation [5], risk management, simulation
of projects expressed as IDEF-0-like diagrams [6], checking the conformance of
element labels to grammatical style rules and for finding modeling anti-patterns
[7]. Thanks to the add-on framework in the bflow* Hive, it was possible to add
all this functionality without having to change the sources of the modeling tool.
3 How to Obtain
The bflow* Hive is already integrated into our own EPC modelling tool bflow*
Toolbox (http://bflow.org), into UPROM [8] (a modeler that allows functional
software size estimation) and into the requirements modeling tool openOME
(http://sourceforge.net/projects/openome/).
The source code can be obtained from https://github.com/bflowtoolbox/app
where all plug-ins named org.bflow.toolbox.hive.* are part of the tool-independent
bflow* Hive. With the help of these plug-ins, modeling tool developers can include
the functionality described in this article into their own Eclipse-based modeling
tool. The easiest way for a user to profit from the features provided by the bflow*
Hive in the modelling language of his or her choice is to download the most recent
version of the bflow* Toolbox from the web site mentioned above and to use
Eclipse’s update mechanism for adding support for other modelling languages.
We are looking forward to reports from people who made use of the bflow* Hive
into their tools, developed file exports, imports or add-ons using our mechanism
or improved the source-code of the bflow* Hive.
Any questions related to our plug-ins are welcome to bflow@bflow.org.
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