jBPM Overview & Alfresco Workflows

JBPM Overview & Alfresco
Workflows
@author: Francesco Valente
@email: francesco83.valente@gmail.com
@franco_valente

./Road map
1. Introduction
Business Process Management
Domain Specific Languages
Graph Oriented Programming
2. jBPM
Overview
Workflows
Process Definition
3. jBPM-jPDL Suite
Installing the jBPM engine
Installing the jBPM Designer
4. jBPM In Action!
Review & Approve workflow
Step-by-Step jBoss jBPM WF
API usage
A Real jBPM use case: Alfresco WF
Step-by-Step Alfresco Advanced Workflow

./Introduction | BPM
Goals of BPM systems?

The main goal of BPM systems is to facilitate the automation of
business processes.
Two main roles can be distinguished:
The business analyst : studies and describes the business
process and specifies the software requirements
The developer : creates executable software

In small teams, these two roles can of course be fullfilled by one
person.

./Introduction | BPM
The business analyst and the developer NEED to communicate in a common
language with the help of the graphical view of the process.

./Introduction |DSL

Each process language
can be considered a
Domain Specific Language (DSL)

./Introduction |DSL

Each language has a certain grammar
That grammar can be expressed as a domain model. (In case
of java this is Class, Method, Field, Constructor,... In jPDL this
is Node, Transition, Action...)
Developers think in those grammars when authoring artifacts
for a specific language. The IDE is build around the grammar
of a language.

E.g. a jPDL process has a graphical editor and a XML source
view editor.

./Introduction |DSL

Internal DSLs are particular ways of using a host language to
give the host language the feel of a particular language. This
approach has recently been popularized by the Ruby
community. Internal DSLs are also referred to as embedded
DSLs or FluentInterfaces
External DSLs have their own custom syntax and you write a
full parser to process them. Many XML configurations have
ended up as external DSLs, although XML's syntax is badly
suited to this purpose.

(www.martinfowler.com)

./Introduction |GOP


Is the foundation for all domain specific languages
that are based on executing a graph.

Is a very simple technique that describes how graphs
can be defined and executed on a plain OOP language

./Introduction |GOP


Two main features:

support for wait states

graphical rappresentation

./Introduction |GOP

Support for wait states

With an imperative language there's no wait instruction
Blocking threads is not a solution: threads are not
persistable
To achive persistance we need a database interaction.
RAM based programs are not sufficients.

./Introduction |GOP

Graphical rappresentation

The communication between a business analyst and the
developer is improved using the graph based diagram of
the business process as the common language.

./jBPM Overview

JBoss JBPM

JBoss JBPM is the open source WFMS (WorkFlow Management
System) suited by JBoss.
JBPM processes are created using a proprietary language of
process definition called jPDL.
State Management with jBPM is based on a graph with nodes
and transitions that make up the definition of a process
(Process Definition).

./jBPM |Workflows
A workflow therefore, consists of a set of activities related to each other
through different types of relationships.
Example: BPMN notation of a process of monitoring the availability of an
agricultural product in stock.

./jPDL |Process Definition
Example: jPDL notation of an approve & reject process of documents.

The graph of the states provides the structure of the process.
The interaction with the process occurs, at "low-level", through the
use of specially designed API.
The actions are business logic (classes that implement the
interface org.jbpm.graph.def.ActionHandler) that can be
performed after special events such as entry in a node, the output
from one node and the transition between states.
The process definitions are contained within the XML file that can
be constructed by hand or by using the graphical tool JBoss jBPM
Graphical Process Designer (GPD) distributed as an Eclipse
plugin.

The definition of a process represent what needs to happen
within the system during a business process and can be
composed of a set of sub-processes.
It is formalized in terms of:
State (node) : A state within a process specifies a
dependency on external actors. At runtime this means
that the workflow engine must wait until an outside actor
notification that the execution has been completed.

Action : An action is the application logic that must be
performed by the workflow engine after the occurrence of
a specific event. Flows of concurrent execution are
modeled with forks and joins, while the exclusive
execution flows are modeled with merge and decision
points.
Transitions : are about moving the process from one
state to another through the application of a
predetermined action.
Process Context : the context of the process managed by
workflow.

./jBPM-jPDL Suite
Architecture

./Installing jBPM-jPDL suite

Step 1/3 - Install Java (easy)

Required java 5.0 or above (I used java 6)
Set properly the environment variable JAVA_HOME


Step 2/3 - Install the jBPM engine and the JBoss
application server
We need exactly the jbpm-jpdl-suite-3.2.3.zip file from this
url
NOTE: Recent versions (recently has been released Version 4 of jBPM) are not
well documented and introduce substantial changes in libraries. Moreover, most
of the resources available on the network relies on this version.

...

The suite is a download that contains all the jBPM components
bundled in one easy download. The download includes the following
folders:
config, configuration files for a standard java environment
db, SQL scripts for DB creation and compatibility information
designer, the eclipse plugin to author jPDL processes and
installation scripts (this is not part of the plain jpdl download ).

...
doc, userguide and javadocs
examples
lib, libraries on which jbpm depends
server, a preconfigured jboss that contains jbpm inside the
console web application (this is not part of the plain jpdl
download)
src, the jbpm and identity component java sources

...

Let's make sure the installation is working correctly:
Go into the server directory and lunch ./start.sh

Open the url http://localhost:8080/jbpm-console/

...
The workflow application bundled with jBPM


Step 3/3 - Install the JBoss jBPM designer
We need Eclipse 3.3.x
NOTE: for the installation of Eclipse jBPM Designer, consult the guide on the
official site of JBoss.

...

./jBPM Workflow |In action!

We'll cover 3 examples:

Review & Approve Workflow

API usage

A real jBPM use case: Alfresco Workflows

./Review & Approve Workflow

Review & Approve (the Hello World)

A simple workflow for approval and rejection of documents.
Consider the case of a news organization that write articles for a
magazine. There are "editors" who write articles and submit
them to review to a group of "approvers" who decide to approve
or deny a particular article.

Process Graphical Design

Process Definition Properties

Two swimlanes :
editors
approvers

Start State Properties

Start State Properties

Process Variables declaration:
Data inizio
Descrizione
(... si potrebbero aggiungere altre variabili
come ad esempio il corpo dell'articolo)

Transition Properties

Transition "submit" start -> review
It's possible to bind it an Action to perform...

processdefinition.xml


The prototype user interface

Before you deploy the process on the JBoss server should
create the so-called "task forms", or graphical user interfaces
pertaining to different tasks, whereby each user can complete
tasks assigned to him.


Generate the task forms

We need to generate one of these task forms for every task
node in our process.

The task forms use XHTML JavaServer Faces tags.


JSF ???

Fortunately we have the jBPM Designer ...

For each task you can automatically generate the form!

submitReviewTask.xhtml

Deploying the process

Investigate the web console
First we create two groups: editors and approvers . Then we add two users
respectively: editor1 and approver1

Investigate the web console

./jBPM API Usage
Hello World Test

./jBPM API Usage
Process Variables Test

./jBPM API Usage
Custom Action Example

./Alfresco Workflows

Alfresco supports two different types of workflow:

Simple Workflow: content-oriented.

Advanced Workflow: task-oriented.

Simple Workflow

Simple Workflow allows you to implement a type of workflow in
which the change of status of the document entails moving the
document from one folder to another folder of an organization
space.

Each state is represented by a folder through which "walk" the
documents and move from one state to the next.

For more details on Simple Workflow consult the official Alfresco
wiki.

Simple Workflow

Limitazioni:

It's impossible to create a workflow definition multi-state;
Confined to one or two output transitions (the only ones
allowed are approve , reject );
It's impossible to define "parallel" workflows;
There is no concept of task or assignment ;

Advanced Workflow

The Advanced Workflow is task-oriented: a task is created, to
which are attached documents, and should be assigned to a
particular user. Each user can track the list of tasks assigned to
him or instantiated from him. It's possible to change the status of a
task, or reassign it to another user, or delete it.

A real use case
In our system we have two workgroups: editors and approvers. And we
have two separated and simmetric spaces or folders into Alfresco, under
the main space called "QBR intranet" : "restricted "and "public" .
Editors have write privileges only on the restricted space.
John, member of the editors group, create his own article and upload it
into any place under the "restricted" folder, then he submit the doc for
approval to every approvers in pooled task mode. If the document will be
approved (by one of the approvers that has taken the ownership of the
revision), the system automatically will copy it from its "restricted" location
into the simmetric "public" location, replicating the tree structure of
subfolders if the case.

A real use case

Components

Components
Process definition
Task Model: provides a description of any human-based tasks within
the process.

The task description is used to guide the dialogue between the user
and the interface in the display and management of the task. Within the
Task Model is used the Alfresco Data Dictionary for a description of the
object types to store, view or modify.
Each task description consists of:
Name e Title
Properties e Associations

Components
Web client configuration: Specifies the presentation of the Task inside
the Alfresco Web Client. The configuration allows you to:
Control which task properties are displayed
Control which task properties are read-only or required
Check how task properties are displayed in the UI.
Resource Bundle (optional): The resource bundle provides all the
human-readable messages that appear in the UI for workflow
management (eg titles of task, the names of properties, etc. ..), thus
facilitating also the location of the UI.

./Creating an Advanced Workflow
Step 1: Create the Process Definition

Two way for creating the process definition document:

1. “By hand” creating a jPDL xml document
2. Using the jBPM Process Designer

Step 1: Create the Process Definition

...processdefinition.xml

Swimlane
Swimlanes are used to declare the roles within the workflow, ie who should do
what.
A special swimlane is called 'initiator' with which the actor in the workflow is the
one that started the workflow.

Pooled Task
A task become a 'pooled task' when it is assigned to a group of people, but only
one of them can take the ownership. Once he has taken ownership, the person
can perform the task, completes it, or he can put it back again in the pool to be
available to other people group.


Alfresco provide all the power of Javascript to
express the business logic within a workflow

Step 2: Deploying into Alfresco

...from the Designer

Through the Process Designer, you can deploy the process on the Alfresco
server:
1. Make sure the Alfresco server is runnin
2. On the Deployment tab enter:
1. Server Name = name of the machine where you installed Alfresco
2. Server Port = port number assigned to Alfresco (default: 8080)
3. Server Deployer = /alfresco/jbpm/deployprocess
3. Press Test Connection ... to test the connection.
4. Finally, Deploy Process Archive.

Step 2: Deploying into Alfresco

...from the Alfresco workflow-console

1. Hand-copy the files related to the process within
/alfresco/extension/workflows/{nome_processo}/

2. Start Alfresco and go in the workflow-console URL
http://localhost:8080/alfresco/faces/jsp/admin/workflow-console.jsp

3. Deploy the new workflow by typing:
deploy alfresco/extension/workflows/{nome_processo}/processdefinition.xml

4. Restart Alfresco

...

Step 3:The Task Model

A Task Model is simply a type of Content Model as supported by the
Data Dictionary. To create a Task Model:

1. Create a new Content Model for the definition of the process.
2. Create a 'type' for each task.
3. Within each 'type' describe Properties and Associations required
for that task.

... reviewPublishModel.xml

A Workflow Package is used to hold the content that's routed through the
workflow. Content within the package may be viewed, edited, or removed.
Some Action Groups available for Workflow Packages:
read_package_item_actions allow viewing of package items
edit_package_item_actions above + allow modification (edit, checkout, ...) of
package items edit_and_remove_package_item_actions above + allow
removal of package items remove_package_item_actions allow removal (but
not modification) of package items

Alfresco provides a pre-registered Content Model for the description of
common attributes to all tasks, which are:
Start Date
Due Date
Completion Date
Priority
Status
Workflow Package
Context
…....

These info are defined in the 'bpm:businessprocessmodel' Model, within
the file alfresco/model/bpmModel.xml . In this model the two most important
type definitions are: 'bpm:workflowTask' and 'bpm:startTask'. All the
custom workflow task definitions must inherit from one of these two onces.
The start-task in the Task Model must inherit from 'bpm:startTask'. Usually in
the Start-task we select participants who have a role within the workflow:
bpm:assignee select a single person.
bpm:assignees select one or more persons.
bpm:groupAssignee select a single group
bpm:groupAssignees select one or more groups.

Step 3: Update the Web client configuration
The configuration allows you to:
Control which Tasks properties are displayed
Control which Tasks properties are read-only or required
Control how Tasks properties are displayed into the UI.

The file interested is the web-client-config-custom.xml :

...web-client-config-custom.xml

Step 4: Create the resource bundle
The resource bundle provides all the human-readable messages that appear in the UI for
workflow management (eg titles of task, the names of properties, etc. ..), thus facilitating
also the location of the UI.

Step 5: Deploy the Task Model and the resource bundle

The Task Model is just a Content Model, so may be deployed like any other Content Model.

./References
jBPM
jBoss jBPMWebsite
http://www.jboss.org/jbossjbpm/

jPDL Guide
http://docs.jboss.com/jbpm/v3.2/userguide/html_single/

jbpm-jpdl-3.2.3.zip
http://bit.ly/j357v

Javadoc API
http://docs.jboss.org/jbpm/v3/javadoc/index.html

[PACKT-BOOK] - "Business Process Management with jBoss jBPM" - Matt
Cumberlidge

./References
Alfresco
Website
http://www.alfresco.com/

Alfresco Wiki
http://wiki.alfresco.com

WorkflowAdministration
http://wiki.alfresco.com/wiki/WorkflowAdministration

Javascript API
http://wiki.alfresco.com/wiki/Workflow_JavaScript_API

[PACKT-BOOK] - "Alfresco Developer Guide" - Jeff Potts

Others
Wikipedia

Mokabyte
http://bit.ly/4D8ZKz

Copyright (C) 2009 - QBR engineering

http://www.qbreng.it

released under
CreativeCommons 3.0 by-nc-sa

NOTE:Some images and contents are property of
the respective copyright
holders and are used for purely
educational purposes.

jBPM Overview & Alfresco Workflows

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