Workflow: Implementing a Document Review Process
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

:Author: Sebastian Bergmann
:Revision: $Revision$
:Date: $Date$
:Status: Draft

.. contents:: Table of Contents


Introduction
============

Business enterprises need to reduce the cost of doing business and continually
develop new services and products. Enterprise Content Management helps with
storing business-critical content (customer data, documents, etc.) in a central
repository and in a unified way. Workflow Management provides the methodologies
and software that help with organizing the processes that operate on this
content inside an organization.

The relationship between Enterprise Content Management and Workflow
Management is analogous to that of attributes (data) and methods (operations on
the data) that are encapsulated in a class in object-oriented programming.

The Workflow component provides a virtual machine that executes workflows
represented through object graphs. These object graphs can be created
programmatically through the software component's Workflow Definition API.
Alternatively, a workflow definition can be loaded from an XML file. Object
graph and XML file are two different but equal representations of a workflow
definition that uses a backend language built on the workflow patterns.


Use Case: Document Review Process
=================================

A common use case for a workflow is modelling how documents are created, edited,
and reviewed. A common approach to this is a five-level approval:

- An author creates or edits a document.
- An editor performs an initial review of the document. The editor can either
  send the document back to its author or approve it.
- Another editor reviews the document for political correctness. The editor can
  either send the document back to the previous reviewer or approve it.
- Another editor reviews the document for sales arguments. The editor can
  either send the document back to the previous reviewer or approve it.
- Another editor performs a grammar check on the document. The editor can either
  send the document back to the previous reviewer or approve it.
- Another editor performs a final review of the document. The editor can either
  send the document back to the previous reviewer or publish it.

The figure below illustrates this document review process.

.. figure:: img/approval_process.png


Modelling the Document Review Process with ezcWorkflow
------------------------------------------------------

.. include:: src/approval_process.xml
   :literal:

.. figure:: img/approval_process_workflow.png


Implementing the Document Review Process with ezcWorkflow
---------------------------------------------------------

Before we can implement the document review process using the Workflow component
we need to create the required tables in our database.

.. include:: src/schema.sql
   :literal:

The following example shows the PHP code that is required to

- Set up the eZ Components autoload mechanism.
- Set up the XML-based workflow definition storage and load the workflow
  definition from an XML file.
- Set up a database connection as well as the database-based workflow definition
  storage and save the workflow definition to a database.
- Set up the database-based workflow executer and start the execution of the.
  workflow.

.. include:: src/approval_process.php
   :literal:


Conclusion
==========

...


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