The pattern language presented in the book consists of 65 patterns structured into 9 categories, which largely follow the flow of a message from one system to the next through channels, routing, and transformations. The book includes an icon-based pattern language, sometimes nicknamed "GregorGrams" after one of the authors. Excerpts from the book (short pattern descriptions) are available on the supporting website (see External links).
Integration styles and types
The book distinguishes four top-level alternatives for integration:
Tightly Coupled Interaction vs. Loosely Coupled Interaction
Messaging
Message Channel
Message
Pipes and Filters
Message Router
Message Translator
Message Endpoint
Message Channel
Point-to-Point Channel
Publish-Subscribe Channel
Datatype Channel
Invalid Message Channel
Dead Letter Channel
Guaranteed Delivery
Channel Adapter
Messaging Bridge
Message Bus
Message Construction
Command Message
Document Message
Event Message
Request-Reply
Return Address
Correlation Identifier
Message Sequence
Message Expiration
Format Indicator
Message Router
Content-Based Router
Message Filter
Dynamic Router
Recipient List
Splitter
Aggregator
Resequencer
Composed Message Processor
Scatter-Gather
Routing Slip
Process Manager
Message Broker
Message Transformation
Envelope Wrapper
Content Enricher
Content Filter
Claim Check
Normalizer
Canonical Data Model
Message Endpoint
Messaging Gateway
Messaging Mapper
Transactional Client
Polling Consumer
Event-Driven Consumer
Competing Consumers
Message Dispatcher
Selective Consumer
Durable Subscriber
Idempotent Receiver
Service Activator
System Management
Control Bus
Detour
Wire Tap
Message History
Message Store
Smart Proxy
Test Message
Channel Purger
The pattern language continues to be relevant as of today, for instance in cloud application development and integration, and in the internet of things. In 2015, the two book authors reunited—for the first time since the publication of the book—for a retrospective and interview in IEEE Software.[1]
