Doing Enterprise Business with Processes & RulesSrinath Perera, Ph.D.

Senior Software Architect WSO2 Inc.

Next 45 Minutes● Leave you with the Big picture

– Why Rules and Business Processes? – For both: What? How does it work?

What can I do with it? When to and not to use it?

– Rules and Business Processes in real world

What is the Secret of Success for Organiza-

tions?How to survive fierce competi-

tion?War and Business are two primary com-

petitions we know in history!Many parallels between war and Business

Art of War is thought in Business school

Value of Knowledge

If you know your enemies and know yourself, you will not be imperiled in a hundred battles -- Sun Tzu

Business at the Speed of Thought

● In Internet scale, we can not do business manually!

● We delegate to Computer● Computer is accurate, fast,

(unfortunately or rather fortu-nately) can not think

● It is crucial to – embed your knowledge

into computer sys-tems

– know what to decide yourself.

But Nothing is Forever

● Any advantage that you hold will disappear over time ● You competition will

– Buy, Steal, Invent, Figure it out, Evolve, or Copy

Everything that has been created is subject

to decay and death. Everything is transitory.

Natural selection

In the struggle for sur-vival, the fittest win out at the expense of their

rivals because they suc-ceed in adapting them-selves best to their en-

vironment. --Charles Darwin

OODA Loop (Boyd Cycle)

● Loop is Observe, Orient, Decide, and Act

● But sooner or later everyone will follow OODA Loop

● Boyd said one win by getting inside others OODA loop

● Which means you have to change fast.

Adaptation

An organization's abil-ity to learn, and trans-late that learning into action rapidly, is the ultimate competitive advantage. --Jack Welch

Agile Organizations● Even organizations are susceptible to theory

of Evolution● Organizations have to change fast. ● In the digital age this means agile organiza-

tions which can adept (who can best adept their systems) has the best chance.

Point Is● Knowledge (how we should act) is the greatest

assert of an organization ● Agile organizations who can understand and

best adopt themselves (knowledge) has best chance of survival

● In the digital age

To change fast, you have to be able to to quickly change knowledge embed-

ded within your systems!

Business Logic● In a Organization, we call this

Knowledge Business Logic ● It is how you do things, your under-

standing, process, formula, al-gorithm, recipe, methodology, query (minus implementation de-tails)

● It the decisions we take –Should we give him a evalu-

ation account ? –Should we make a partner-

ship with X?–Should we give him Free

Shipping?–What is the best Prize?–Should I raise my Bid?

Business Logic Separation● Business logic changes much faster than rest

of the system ● If your code and logic are mesh together, it is a

nightmare to change them.

We need to sep-arate the Business

logic from code

Typical Architecture● Mash all together architecture ● 3 tire architecture● Even with 3 tier architecture still logic is buried in the code

within services ● Good luck in locating and changing them.

What do we need?● Separated Business logic ● Store and manage (edit, share, delete) them in a one

place and through one User Interface.● If possible in easy to understandable form ● Edit them Visually when possible.

Let's discuss two ways to implement this separ-

ation: Rules and Business

Process

Business Rules

What are Rules?You must always drive from the left (or was it right?)

You should not Eat Chocolates (Then

pass me a ice cream please!)

What are Rules? (Contd.)● It is a knowledge representation. (usually partial

knowledge) ● Four types

1)Derivation or Deduction Rules – Each rule express if some statements are true, another statement must be true. Called logical implication. E.g. Prolog

2)Transformation Rules- transform between knowledge bases, e.g. theorem proving

3)Integrity Constraints – verification rules 4)Reaction or Event-Condition-Action (ECA) Rules

– includes an actions in addition to inference. e.g. Drools

How do Rules work?● Data represented as Facts ● Knowledge represented as Rules● A Rule engine evaluates Facts against Rules, and optionally

carry out specified actions. (e.g Drools, JESS)

Two types of Rules Engines: ● Forward Chaining – starts with

facts/data and trigger actions or output conclusions (Drools)

● Backward chaining – starts with goals and search how to satisfy them (e.g. Prolog)

Why Rules?● Externalize the business logic (which are too dy-

namic) from comparatively static code base● Simplify complicated requirements with declarative

logic, raising the level of abstraction of the system● Intuitive and readable than code, easily under-

stood by business people/ non technical users● Create complex interactions which can have

powerful results, even from simple facts and rules.● Different approach to the problem, some problems

are much easier using rules.● Fast and scalable when there is a data set that

changes little by little

When to use Rules?● To separate code and business lo-

gic● When the logic changes often ● When Domain experts are none

technical. ● When all else failed! (When there is

no satisfactory traditional program-ming approach to solve the prob-lem! Rules are good in solving prob-lems that are not fully understood).

When NOT to use Rules?● It is slower than usual code most of the time, so unless there

are obvious benefits ● Complexity of logic is hard to tackle, and one mistake could

change the results drastically and in unexpected ways (e.g. recursive rules)

● More effort for testing and debugging is required, so if results are hard to be verified, it should not be used.

Rules in SOA

● As a Service (e.g. BRS), As a Mediator (E.g. WSO2 ESB)● Stored in a registry and referred, so they can be edited and

found in one place, versioned, reverted back, tested separ-ately

Rules in Action?● Decision tables – in a bidding system, map the bidding rules

to a Decision table implemented with a Excel file. Business analysts can change the Excel file and change Business logic of the system.

● A Domain Specific Language that interfaces with rules are used to describe when free shipping offers should be given to the user. Business analysts change the DSL scripts stored in the registry, and Business logic of the system changes.

● Rules are used to route documents between several de-partments to increase the processing efficiency. When a new pattern is observed, it can be easily added.

● Rules are used to detect error conditions in a complex de-ployment and it is easy to add new error conditions by adding new rules.

Business Processes

What is Processes?

Baking A Cake?

Conduct a Orchestra

Production Line

What are Processes?● Process captures a set of activities designed to

achieve a specific goal. ● It is a formula, or algorithm, recipe etc. ● Unlike rules, activities in a process are very well con-

nected with each other (a clear flow). ● Examples

– Adding a new employee: Sign the contract, create an account, assign to a team, give permissions, assign a seat, order hadrware etc.

– Release a Product: Design, develop, test, market, ..

Sample Business Processes● Nodes (services) are connected via dataflows (dependencies)

or control flows (If, then, while).

How do Business Processes Work?● Business process is described using a Workflow language

(e.g. BPEL, BPMN, Python, Java Script)● Just like a java script runtime executes java scripts, a workflow

engine executes the workflow description. – e.g. Apache ODE, WSO2 BPS, MS Workflow Founda-

tion, Dryad by MSR etc.

● It is a programming language:● Support messaging, asyn-

chronous invocations etc. as first class

● Real difference lies in the level of abstraction. Curiosity is good,

unless you are a cat

Why Processes?● Abstract out the business logic ● A different level of abstraction to

manage the logic

● Special features– Can be visualized, analyzed, and verified – Execution can be monitored – Execution can be hibernated and resumed – Failed workflows can be recovered– Can visually composed – Workfows can be manipulated at runtime

When to use Processes?● To abstract out the Business Logic ● When there are many reusable com-

ponents (services) that can be com-posed together (Mathlab like environ-ments)

● Easy way to evolve the logic (edit)● For long running processes where

monitoring, recovery, hibernation are expected.

● When we want to track how business process evolution took place (through provenance)

When NOT to use Processes?● Workflows are often slower than normal code● Add dependency to new tools (workflow engine), complex to

setup and harder to debug. ● When logic is too complex (consider implementing complex

parts as services)● Do not use unless there are clear benefits

Business Process Execution Language (BPEL)

● A programming abstraction that allows developers to compose multiple synchronous and asynchronous Web services into an end-to-end business flow

● Constructs:– Messaging: invoke, receive, reply, assign, – Structured: sequence, flow, if, while, repeatUntil– Exception handling: fault Handlers (throw catch) – Event processing: onMessage, onAlarm

● Human Task extensions: Let workflows interact with humans

● BPMN (Business Process Modeling Notation) – a visual notation for workflows.

Processes in Action● A Service composition Environment: Expose

a set of tools as services and use workflows to create an environment where users can compose (mash) them to create interesting processes.

– E.g. Science toolkit ● Governance workflows: Workflows to capture

processes associated with services in a registry dev->test->production environment

● Modeling Internal process of an organiza-tion as Workflows

● Long running business processes: (ability to hibernate, recover, and monitor executions)

– e.g. Long running scientific worklflows.

Rules vs. Processes

●

●

Processes are for well under-stood problems where sequence of actions get us

into expected state. (e.g. Cook-

ing)

Rules are for partially under-stood (AI like heuristic driven)

problems. e.g. Chess

Conclusion● Knowledge (Business Logic) is the greatest

assert to a organizations ● Organizations that can adept themselves to

change have the best chance of survival ● Separating the Business logic from the code

enables Business logic to evolve and man-aged separately

● Business Rules and Business processes are two ways to extract out business logic.

● We discussed them and their applications with-in Enterprise Architecture.

Questions?