Cress (Communication Representation Employing Systematic Specification)

See the download page about obtaining this under licence

The current version of Cress is 4.6, dated 27th October 2010.

Overview
Tools
Required Environment
Licence

Overview

Cress is an acronym for Communication Representation Employing Systematic Specification. This page is an extract of the full manual. See the Cress home page for an overview of Cress and some references. Cress allows graphical description of (communications) services, translates them into formal languages for rigorous analysi, and translates them into implementation languages for deployment. It supports:

diagrams for the following kinds of services, though the approach is extensible for other domains:

DS (Device Services, i.e. BPEL/WSDL with OSGi)
GS (Grid Services, i.e. BPEL/WSDL)
IN (Intelligent Network)
IVR (Interactive Voice Response, i.e. VoiceXML)
SIP (Session Initiation Protocol, i.e. Internet Telephony)
VoIP (Voice over Internet Protocol, i.e. Internet Telephony with SIP/CPL)
WS (Web Services, i.e. BPEL/WSDL)

parsing of service diagrams prepared with one of the following editors, though the approach is extensible for other graphical editors:

Chive
Diagram!
yEd

checking of service diagrams for syntactic and static semantic correctness
translation of service diagrams into the following target languages, though the approach is extensible for other languages:

BPEL/WSDL
CPL
Lotos
SDL
VoiceXML

miscellaneous utilities

From the user point of view, Cress simplifies service creation to the point of drawing diagrams, clicking buttons and issuing simple commands.

From the developer point of view, Cress is a complex but comprehensive toolset. It is roughly equivalent to six compilers rolled into one, as it supports three diagram editors, six target languages, and five application domains. A relevant quote for Cress might be:

Ὓδραν τέμνεις
("You are cutting into a Hydra", Plato, Republic 426)

Tools

The following main tools are provided in the Cress toolset:

Tool	Purpose
`cadp_annotate`	annotate Lotos for use by CADP
`cress_bpel`	translate Cress diagrams to BPEL
`cress_check`	check Cress diagrams
`cress_cpl`	translate Cress diagrams to CPL
`cress_create`	create BPEL service archives
`cress_deploy`	deploy BPEL service archives
`cress_expand`	expand macros in Cress diagrams
`cress_lola`	clean up Lola (Lotos) simulation traces
`cress_lotos`	translate Cress diagrams to Lotos
`cress_realise`	specify/implement/deploy Cress diagrams
`cress_sdl`	translate Cress diagrams to SDL
`cress_sdt`	turn a Lola (Lotos) test process into an MSC/PR file for Tau SDT (SDL)
`cress_test`	run JUnit tests on BPEL services
`cress_tidy`	delete temporary Lola (Lotos) and Tau SDT (SDL) files
`cress_validate`	validate Cress diagrams
`cress_verify`	verify Cress diagrams
`cress_vxml`	translate Cress diagrams to VoiceXML
`sdt_in` `sdt_sip` `sdt_vxml`	these are Tau Analyzer filters for IN, SIP and VoiceXML; set them as a filter in the Tau SDT Analyzer dialogue

These in turn rely on various Perl modules:

Module	Purpose
`cress_bpel.pm`	Cress diagram to BPEL/WSDL translator; variants apply for each vocabulary
`cress_common.pm`	Cress common definitions
`cress_cpl.pm`	Cress diagram to CPL translator;
`cress_lexer.pm`	Cress lexical analyser (diagram analyser)
`cress_lotos.pm`	Cress diagram to Lotos translator; variant code applies for each vocabulary
`cress_parser.pm`	Cress diagram parser (syntax analyser)
`cress_sdl.pm`	Cress diagram to SDL translator; variant code applies for each vocabulary
`cress_vxml.pm`	Cress diagram to VoiceXML translator
`cress_vocab.pm`	Cress vocabularies

The relationship among the main scripts is as follows:

Required Environment

General

To run these tools requires a Unix-like environment and Perl 5. The tools have been run on Unix (Fedora Core 4, NextStep 3.3/OpenStep 4.2, Solaris 7/8) and Windows (XP, under CygWin 1.5/1.7).

Diagram Editor

The best alternative is to make use of the Chive graphical editor created for Cress. This is Java-based and should run on many platforms. Virtually all Cress diagrams have been provided in Chive XML format.

If Java is supported on your platform, you can use yEd instead. Download this from yWorks. Diagrams need to be saved in GML format for Cress to use them. yEd will read .gml format as well as its own .ygf format.

If you are able to run NextStep/OpenStep, you can edit and create Cress diagrams. You may be able to download Diagram! and a licence key from the Web, though the author has local copies. The file cress.dpalette2 is a palette for this diagram editor.

Diagrams can be checked individually or in groups by running cress_check.

BPEL

To deploy and run generated Web Services, you will need Apache Tomcat (e.g. version 5.5.12 onwards) and ActiveBPEL (e.g. version 5.0.2). To test web or grid services requires JUnit 4.0 or later and MySQL 5.0 or later. To deploy and run generated Grid Services, you will also need Globus WS Core (e.g. version 4.2).

Beware of some version incompatibilities in these external tools:

ActiveBPEL versions 3.N onwards require a JVM version 1.5.

CPL

To deploy and run generated CPL, you will need a CPL-capable SIP server such as SER (SIP Express Router) or Vocal.

Lotos

To analyse and execute the generated specifications, you will need Lola/Topo (e.g. version 3.6 onwards). The author has a version of Lola/Topo compiled for CygWin on Windows and Debian Linux. You might also wish to use CADP (e.g. version 7.1 onwards). Cress descriptions can be verified with Clove (Cress Language-Oriented Verification Environment) and can be validated with Mustard (Multiple-Use Scenario Testing and Refusal Description).

SDL

To analyse and execute the generated specifications, you will need Telelogic Tau SDL Suite or SDL/MSC (e.g. version 4.6 onwards).

VoiceXML

To deploy and run Cress IVR services, you will need V-Builder and associated packages from Nuance Corporation (e.g. version 1.2 onwards). This is a substantial and complex set of downloads that needs registration and approval by Nuance. At least Nuance V-Builder, Nuance Vocalizer and a Nuance language pack will be needed.

Licence

This is not open-source software. The authors (Kenneth J. Turner and others, University of Stirling) retain copyright in it. Nonetheless, the authors will normally approve its use by others subject to the following conditions:

The software will be provided for use only within an organisation that accepts this licence. The software may not be distributed outside this organisation.
The software may be used only for purposes of an investigative and non-commercial nature. The software may be used freely for these purposes. Diagrams and code supplied by the author are the property of the author. However, anything additional created by the user (including generated code) is the property of the user.
The software is provided without any warranty or guarantee as to its reliability or fitness for purpose. No responsibility is accepted by the author for direct or indirect consequences of using the software.
Enhancements and corrections to the Cress diagrams and code supplied must be made freely available to the author.

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