A Workflow Engine for PHP 5

Slide 1: ezcWorkflow A Workflow Engine for PHP 5 Sebastian Bergmann http://sebastian-bergmann.de/

Slide 2: Who I Am • Sebastian Bergmann • Computer Scientist • Involved in the PHP Project since 2000 • Author, Consultant, Coach, Trainer • Developer for eZ Systems AS Sebastian Bergmann: A Workflow Engine for PHP 5 2

Slide 3: Who are you? • Your experience with PHP 5? ● OOP? ● eZ Components? ● Workflow? ● Sebastian Bergmann: A Workflow Engine for PHP 5 3

Slide 4: 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. Sebastian Bergmann: A Workflow Engine for PHP 5 4

Slide 5: What is Workflow Management? “The automation of a business process, in ● whole or parts, where documents, information or tasks are passed from one participant to another to be processed, according to a set of procedural rules” [RA01] Sebastian Bergmann: A Workflow Engine for PHP 5 5

Slide 6: What is Workflow Management? “Technology supporting the reengineering of ● business and information processes. It involves: (1) defining workflows, i.e., describing those aspects of a process that are relevant to controlling and coordinating the execution of its tasks [...], and (2) providing for fast (re)design and (re)implementation of the processes as business needs and information systems change” [DG95] Sebastian Bergmann: A Workflow Engine for PHP 5 6

Slide 7: Motivation The Workflow of eZ Publish 3 Sebastian Bergmann: A Workflow Engine for PHP 5 7

Slide 8: Activity-Based Workflow Mgmt. Who must do what when and how? Sebastian Bergmann: A Workflow Engine for PHP 5 8

Slide 9: Activity-Based Workflow Mgmt. Who must do what when and how? • Directed Graph – Nodes represent activity steps – Edges between nodes represent the flow • Control Flow • Data Flow – Nodes can have service objects attached to them Sebastian Bergmann: A Workflow Engine for PHP 5 9

Slide 10: Workflow Patterns • W.M.P. van der Aalst, A.H.M. ter Hofstede, B. Kiepuszewski, and A.P. Barros. Workflow Patterns. • Requirements for Workflow Languages • Vocabulary to compare Workflow Languages Sebastian Bergmann: A Workflow Engine for PHP 5 10

Slide 11: Workflow Patterns • Basic Control Flow Patterns – Sequence, Parallel Split (AND-Split), Synchronization (AND-Join), Exclusive Choice (XOR-Split), Simple Merge (XOR-Join) • Advanded Branching and Synchronization – Multi-Choice (OR-Split), Synchronizing Merge (OR-Join), Multi-Merge, Discriminator • Structure – Arbitrary Cycles, Cancel Case, Implicit Termination Sebastian Bergmann: A Workflow Engine for PHP 5 11

Slide 12: Graph-Oriented Programming • Implementation technique for graph-based execution languages • Strategy for implementing graph execution on top of an object-oriented programming language • Original implementation: JBoss jBPM Sebastian Bergmann: A Workflow Engine for PHP 5 12

Slide 13: Graph-Oriented Programming • Provides the means to structure software around graphs • Adds wait states to object-oriented programming language – Ability to suspend and resume executions Sebastian Bergmann: A Workflow Engine for PHP 5 13

Slide 14: Graph-Oriented Programming Sebastian Bergmann: A Workflow Engine for PHP 5 14

Slide 17: Workflow Virtual Machine • Sérgio Miguel Fernandes, João Cachopo, and António Rito Silva. Supporting Evolution in Workflow Design Languages. • Isolate the core of the Workflow Management System from the Workflow Description Language – No standard Workflow Description Language – Workflow Description Languages change • Compile frontend Workflow Description Language(s) to backend representation Sebastian Bergmann: A Workflow Engine for PHP 5 17

Slide 18: Micro-Workflow Architecture • Dragos A. Manolescu. An Extensible Workflow Architecture with Objects and Patterns. • Object-Oriented – Original implementation in Smalltalk • Component-Oriented – Separation of concerns – Components are exchangeable Sebastian Bergmann: A Workflow Engine for PHP 5 18

Slide 19: Micro-Workflow Architecture • Components – Core • Execution • Process • Synchronization • Persistence • Worklist • Manual Intervention • History • Monitoring • Federated Workflow Sebastian Bergmann: A Workflow Engine for PHP 5 19

Slide 20: ezcWorkflow • Reusable workflow engine component • Part of the eZ Components – Version 1.0 released on July 2nd 2007 • Developed as part of my Diploma Thesis Sebastian Bergmann: A Workflow Engine for PHP 5 20

Slide 21: Interlude: eZ Components • Provide a solid platform for PHP application development • Clean and simple API • Excellent documentation • Keep backward compatibility for longer periods of time • Stable and few regressions • Clean IP, Open Source friendly Sebastian Bergmann: A Workflow Engine for PHP 5 21

Slide 22: Interlude: eZ Components • pear channel-discover components.ez.no • pear install ezc/ezcomponents <?php require 'ezc/Base/base.php'; function __autoload( $className ) { ezcBase::autoload( $className ); } Sebastian Bergmann: A Workflow Engine for PHP 5 22

Slide 23: ezcWorkflow • Pragmatic approach to describe workflows through objects that encapsulate the workflow patterns • A workflow definition is an object graph than can be – programmatically created using the Workflow Definition API or – loaded from an XML file – and executed via the Workflow Execution API Sebastian Bergmann: A Workflow Engine for PHP 5 23

Slide 24: ezcWorkflow GUI XML Mail / SOAP / ... Wf Definition API Wf Execution API Workflow Core Data Storage Sebastian Bergmann: A Workflow Engine for PHP 5 24

Slide 25: ezcWorkflow • Workflow Definition API – Exposes functionality to create, modify, and delete workflow definitions • Workflow Execution API – Exposes functionality to start, suspend, resume, and stop workflow execution – Exposes functionality to monitor workflow execution Sebastian Bergmann: A Workflow Engine for PHP 5 25

Slide 26: ezcWorkflow Example: Defining a workflow programmatically $workflow = new ezcWorkflow( 'Test' ); $input = new ezcWorkflowNodeInput( array( 'choice' => new ezcWorkflowConditionIsBool ) ); $workflow->startNode->addOutNode( $input ); Sebastian Bergmann: A Workflow Engine for PHP 5 26

Slide 27: ezcWorkflow Example: Defining a workflow programmatically $branch = new ezcWorkflowNodeExclusiveChoice; $branch->addInNode( $input ); $branch->addConditionalOutNode( new ezcWorkflowConditionVariable( 'choice', new ezcWorkflowConditionIsTrue ), new ezcWorkflowNodeAction( 'PrintTrue' ) ); // ... Sebastian Bergmann: A Workflow Engine for PHP 5 27

Slide 28: ezcWorkflow Example: Defining a workflow programmatically $merge = new ezcWorkflowNodeSimpleMerge; $merge->addInNode( $true ) ->addInNode( $false ) ->addOutNode( $workflow->endNode ); Sebastian Bergmann: A Workflow Engine for PHP 5 28

Slide 29: ezcWorkflow Example: Saving a workflow definition to XML $merge = new ezcWorkflowNodeSimpleMerge; $merge->addInNode( $true ) ->addInNode( $false ) ->addOutNode( $workflow->endNode ); $storage = new ezcWorkflowDefinitionStorageXml( '/path/to/xml/files' ); $storage->save( $workflow ); Sebastian Bergmann: A Workflow Engine for PHP 5 29

Slide 30: ezcWorkflow Example: Saving a workflow definition to XML <?xml version="1.0" encoding="UTF-8"?> <workflow name="Test" version="1"> <node id="1" type="Start"> <outNode id="2"/> </node> <node id="2" type="Input"> <variable name="choice"> <condition type="IsBool"/> </variable> <outNode id="3"/> </node> <node id="3" type="ExclusiveChoice"> <condition type="Variable" name="choice"> <condition type="IsTrue"/> <outNode id="4"/> </condition> <condition type="Variable" name="choice"> <condition type="IsFalse"/> <outNode id="5"/> </condition> </node> <node id="4" type="Action" serviceObjectClass="PrintTrue"> <outNode id="6"/> </node> <node id="5" type="Action" serviceObjectClass="PrintFalse"> <outNode id="6"/> </node> <node id="6" type="SimpleMerge"> <outNode id="7"/> </node> <node id="7" type="End"/> </workflow> Sebastian Bergmann: A Workflow Engine for PHP 5 30

Slide 31: ezcWorkflow Example: Saving a workflow definition to a database $merge = new ezcWorkflowNodeSimpleMerge; $merge->addInNode( $true ) ->addInNode( $false ) ->addOutNode( $workflow->endNode ); $storage = new ezcWorkflowDatabaseDefinitionStorage( ezcDbFactory::create( $dsn ) ); $storage->save( $workflow ); Sebastian Bergmann: A Workflow Engine for PHP 5 31

Slide 32: ezcWorkflow Example: Executing a workflow $execution = new ezcWorkflowDatabaseExecution( $db ); $execution->setWorkflow( $workflow ); $executionId = $execution->start(); // ... $execution->resume( $executionId, array( 'choice' => true ) ); Sebastian Bergmann: A Workflow Engine for PHP 5 32

Slide 33: ezcWorkflow Example: Testing a workflow $execution = new ezcWorkflowTestExecution; $execution->setWorkflow( $workflow ); $execution->setInputVariable( 'choice', true ); $execution->start(); Sebastian Bergmann: A Workflow Engine for PHP 5 33

Slide 34: ezcWorkflow Early Adopters • OXID eSales GmbH has adopted ezcWorkflow – Thomas Nunninger (of OXID eSales GmbH) has developed a persistence backend for Zend_Db • Dave Heath has developed a persistence backend for Doctrine – He is also working on an AJAXy workflow editor Sebastian Bergmann: A Workflow Engine for PHP 5 34

Slide 35: The End • Thank you for your interest! • These slides will be available shortly on http://sebastian-bergmann.de/talks/ Sebastian Bergmann: A Workflow Engine for PHP 5 35

Slide 36: License • This presentation material is published under the Creative Commons Attribution- NonCommercial-NoDerivs 3.0 Unported license. • You are free: – to Share – to copy, distribute and transmit the work. • Under the following conditions: – Attribution. You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). – Noncommercial. You may not use this work for commercial purposes. – No Derivative Works. You may not alter, transform, or build upon this work. • For any reuse or distribution, you must make clear to others the license terms of this work. The best way to do this is with a link to this web page. • Any of the above conditions can be waived if you get permission from the copyright holder. • Nothing in this license impairs or restricts the author's moral rights. Sebastian Bergmann: Qualitätssicherung in PHP-Projekten 36

Slideshare.net (beta)