Doernenburg_EnterpriseIntegration

8/3/2019 Doernenburg_EnterpriseIntegration

1/34


2/34

EMEA

2

Enterprise Integration

Erik Doernenburg

ThoughtWorks, Inc.

[email protected]


3/34

EMEA

Copyright ThoughtWorks, Inc. 20053

Agenda

Challenges in enterprise application development

Design patterns

Enterprise Integration patterns

Interop technologies

Conclusion & Resources


4/34

EMEA


The challenge

Enterprises depend on a growing number of IT systems

The systems must provide an integrated solution for theenterprise

The systems must interoperate with each other

Architectural trends and waves of technologies

Changing business needs and requirements


5/34

EMEA


Existing Systems

New System

Finance Operator Application

Workflow items are stored on Tibco RV/CM queue

Tibco Integration Manager organises workflow

handles imports from document recognition

handles interaction with existing ERP systems

Reference data imported using linked servers

fax/telex

email

mail document

recognition

app web

ERP ref. data


6/34

EMEA


New application

Existing

Portfolio Management Tool

Front-end uses Office 2003code-behind technology

communicates with server using

WebSphere MQ queues

Message format defined withXSD schema

Application uses existing services accesses analytics library with

COM bridge

accesses stored deals throughdeal manager service

accesses service bus through

messaging abstraction library

analytics

library

Existing

deal

manager

Existing

messaging

library

technology

adaptor

Excelfront-end

application

logic


7/34

EMEA

7

Design Patterns


8/34

EMEA


Why design patterns?

Code reuse remains difficult

but

Knowledge reuse can be very valuable

Patterns encapsulate knowledge of successful designs


9/34

EMEA


Using technology successfully

Syntax

Basic language mechanism

A necessity but not a guarantee

Constructs

Classes, Interfaces, Inheritance, Polymorphism, etc. Helpful but not sufficient for good design

Principles

Separation of concerns, Dependency Injection, etc.

Steer us towards a better solution

Patterns

Model-View-Controller, Observer, Decorator

Concrete design guidance


10/34

EMEA


Patterns

Mind sized chunk of information (Ward Cunningham)

Shows a good solution to a common problem within a

specific context

Observed from actual experience

Has a distinct name

Not copy-paste

ThoughtWorks collaborates with Microsoft to document

design patterns for the .NET platform


11/34

EMEA


Enterprise Integration Patterns

Gregor Hohpe defined a visual pattern language describing

message-based enterprise integration solutions

Pattern language comprises 65 patterns in 6 categories

Application

A

Application

B

MessageChannel

Router TranslatorEndpoint Endpoint

MonitoringMessaging

Endpoints

MessagingChannels

MessageConstruction

Message

Routing MessageTransformation

System

Management


12/34

EMEA


Pattern: Request-Response

Service Consumer and Provider (similar to RPC)

Channels are unidirectional

Two asynchronous point-to-point channels

Separate request and response messages

Request Channel

Response

Request

Reply Channel

ProviderConsumer


13/34

EMEA


Multiple consumers

Each consumer has its own reply queue

But how does the provider send the response?

Could send to all consumers (very inefficient)

Hard code (violates principle of context-free service)

Responses

Requests

?

Requests

Request Channel

Reply Channel 1

Reply Channel 2

ProviderConsumer 1

Consumer 2


14/34

EMEA


Pattern: Return Address

Consumer specifies Return Address (the reply channel)

in the request message

Service provider sends response message to specified

channel

Responses

Reply

Channel 1 ReplyChannel 2

Request Channel

Reply Channel 1

Reply Channel 2

ProviderConsumer 1

Consumer 2


15/34

EMEA


Load-balanced service providers

Request message can be handled by multiple providers

Point-to-pointchannel supports competing services

Only one service receives each request message

But what if the response messages are out of order?

Request Channel

Reply Channel

Provider 1

Provider 2

Consumer


16/34

EMEA


Pattern: Correlation Identifier

Consumer assigns a unique identifier to each message

Identifier can be an arbitrary ID, a GUID, a business key

Provider copies the ID to the response message

Consumer can match request and response

Message

Identifier 1

2

1 2

1212

1 2

12

Correlation

Identifier

Request Channel

Reply Channel

Provider 1

Provider 2

Consumer


17/34

EMEA


Multiple specialised providers

Each provider can only handle a specific type of message

Route the request to the "appropriate" provider. But how?

Do not want to burden sender with decision

Letting providers "pick out" messages requires

coordination

Order

Entry

Widget Inv.

?

Order Messages

Gadget Inv.


18/34

EMEA


Pattern: Content-Based Router

Insert a content-based router

Routers forward incoming messages to different channels

Message content not changed

Mostly stateless, but can be stateful, e.g. de-duper

Order

Entry

Widget Inv.Order Messages

Gadget Inv.

ContentBased

Router


19/34


20/34

EMEA


Pattern: Splitter & Router

Use a splitter to break out the composite message into a

series of individual messages

Then use a router to route the individual messages as before

Note that two patterns are composed

Widget Inv.

Gadget Inv.

Order

Entry

RouterSplitter

Order

MessageOrder

Items

Order

Item 1

Order

Item 2


21/34

EMEA


Producing a single response

How to combine the results of individual but related

messages?

Messages can be out-of-order, delayed

Multiple conversations can be intermixed

Widget Inv.

Gadget Inv.

Billing

Order

Item 1 Response 1

Order

Item 2Response 2

Confirmed

Order

?


22/34


23/34

EMEA


Communicating with multiple parties

How to send a message to a dynamic set of recipients?

And return a single response message?

Request

For Quote

Vendor A

Vendor B

Quotes

AggregatorBest

Quote

Vendor C?


24/34

EMEA


Pattern: Scatter-Gather

Send message to a pub-sub channel

Interested recipients subscribe to a "topic"

Aggregator collects individual response messages

may not wait for all quotes, only returns one quote

Request

For Quote

Vendor A

Vendor B

Quotes

AggregatorBest

Quote

Vendor C

Pub-Subchannel


25/34

EMEA


Complex composition

Receive an order message

Use splitter to create one message per item

Send to scatter/gather which returns "best quote" message

Aggregate to create quoted order message

Quote request

for each item

Vendor A

Vendor B

Quotes

AggregatorBest Quote

for each item

Vendor C

Aggregator

Splitter

Pub-Subchannel


26/34

EMEA

29

Interop technologies


27/34

EMEA Copyright ThoughtWorks, Inc. 200530

Resource based

RPC style / distributed objects

Message based / document-oriented

Major interop technologies

DB files

RMI-IIOP

(CORBA)

MOM

in-process

bridge

WS-*

WSRemoting

(DCOM)

WS


28/34


Interop technology characteristics

point-to-point

transient messages

durable message

server lifetime-

management

bridgeRemoting

(DCOM)

RMI-IIOP

(CORBA)WSMOMDB/files

routable

WS-*

clustering

in-proc.NETserver

J2EEserver

platformneutral

WSMOM WS-*


29/34


30/34


Why Web Services?

Web services provide all benefits of messaging solution

loose-coupling

service oriented

reliable communication

Why web services?

composable protocol

vendor neutral

suitable for access through Internet


31/34


Web Services development

Web Services are expected to become the default Messaging

solution in the future

WS-* standards are evolving rapidly, most important

WS-Security

WS-Policy

WS-Addressing

WS-I defines profiles, sample applications and testing tools

Profiles are guidelines for using WS specifications

Use Basic profile 1.1 to build interoperable solutions

Further research on WS is being carried out


32/34


Conclusion

Enterprise systems are becoming more complex

We have patterns to help us with the design

We have technologies to implement our designs

Building for interoperability and integration is key


33/34


34/34

Please complete your session

feedback form

THANK YOU

Documents

Doernenburg_EnterpriseIntegration