Elementary Middleware Communication Patterns for a Successful SOA Implementation Any complex communication scenario can be efficiently built from a small number of atomic patterns Atomic SOA Patterns

SOA Application Layer Model (non-OSI) Canonical Content representation Content HTML, XML, JSON, ASCII Envelope HTTP, FTP, WebDAV, Steganographie Transport TCP, UDP, IPX Delivery IP Data Linkage Ethernet, Token-Ring Network WLAN, Cable, Sound, File-System Physical

Canonical Data Transport von Neumann Paradigm of Computing: Communication as canonical 3-step process  Input  Process  Output von 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. János von Neumann zu Margitta: Mastermind of modern Computer Architecture

Example: How to copy a file The quick & dirty approach Procedure CopyFile Read the input file Convert encoding Save the file The quick & dirty approach Procedure 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 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

Data Transport in Envelopes

Interaction Transport/Data-Layer

Atomic Patterns

Sender

Peer-to-Peer SR Message directly from Sender to Receiver source sink SR M

Peer-to-Peer with conversion SR Message converted either by Sender or Receiver sourcesink SR CC M mm sourcesink SR CC M mm

Message-Broker (Middleware) Message converted in a message-oriented middleware broker sourcesink SR CC M mm MoM

Message-Queue Buffer message in queue until receiver is ready sourcesink SR CC M mm MoM Q 

Message-Rerouting Redirect message based on rules e.g. Load balancing, quarantine sourcesink SR CC M mm MoM sink 2 R Rule

Message Fan-out Replicate messages based on rules e.g. mass source Sink 1 S R CC M MoM sink 2 R Rule mm sink 3 R