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Elementary Middleware Communication Patterns for a

Successful SOA ImplementationAny complex communication scenario can be efficiently built from a

small number of atomic patterns

Atomic SOA Patterns

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SOA Application Layer Model (non-OSI)• Canonical Content representationContent• HTML, XML, JSON, ASCIIEnvelope• HTTP, FTP, WebDAV, SteganographieTransport• TCP, UDP, IPXDelivery• IPData Linkage• Ethernet, Token-RingNetwork• WLAN, Cable, Sound, File-SystemPhysical

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Canonical Data Transportvon Neumann Paradigm of Computing:Communication as canonical 3-step process Input Process Output

Data exchange within a layer happens always via a Canonical Format.Data exchange between layers is only done through defined gateways. Input Process Output

János von Neumann zu Margitta:Mastermind of modern Computer Architecture

Receive Process Send

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Example: How to copy a file

The quick & dirty approachProcedure CopyFile

• Read the input file• Convert encoding• Save the file

The atomic approach• Procedure readFile

• Read the input file• Procedure convertEncoding

• Convert encoding• Procedure saveFile

• Save the file• Procedure CopyFile

• Call inputFile• Call convertEncoding• Call saveFile

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Physical Format

Transport protocol

HTTP, FTP, FileSys

Transport Envelope

Protocol specific

HTML, JSON, Text

Canonical FormatInternal container format

Data Transport in Envelopes

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Interaction Transport/Data-Layer

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Atomic Patterns

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Sender

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Peer-to-Peer

Message directly from Sender to Receiver

source sink

S RM

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Peer-to-Peer with conversion

Message converted eitherby Sender or Receiver

source sink

S RCM m

source sink

S RCM m

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Message-Broker (Middleware)

Message converted in a message-oriented middleware

broker

source sink

S RC

M m

MoM

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Message-Queue

Buffer message in queue until receiver is ready

source sink

S RC

M mMoM

Q

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Message-Rerouting

Redirect message based on rulese.g. Load balancing, quarantine

source sink

S RC

M

m

MoM

sink 2

RRule

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Message Fan-out

Replicate messages based on rules

e.g. mass email

source Sink 1

S RC

MMoM

sink 2

R

Rule

m

sink 3

R