Enterprise Integration Patterns
This page describes the various Camel supports most of the Enterprise Integration Patterns which are implemented by Camel.
Message Routing
from the excellent book by Gregor Hohpe and Bobby Woolf.
If you are new to Camel you might want to try the Getting Started in the User Guide before attempting to implement these patterns.
The EIP icons library is available as a Visio stencil file adapted to render the icons with the Camel color : sand. Download it here for your presentation, functional and technical analysis documents. The original EIP stencil is also available in OpenOffice 3.x Draw (thanks to Marco Garbelini) , Microsoft Visio, or Omnigraffle.
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Messaging Systems Image Added
| Message Channel | How does one application communicate with another using messaging? |  Image Added
| Message | How can two applications connected by a message channel exchange a piece of information? |  Image Added
| Pipes and Filters | How can we perform complex processing on a message while maintaining independence and flexibility? |  Image Added
| Message Router | How can you decouple individual processing steps so that messages can be passed to different filters depending on a set of conditions? |  Image Added
| Message Translator | How can systems using different data formats communicate with each other using messaging? |  Image Added
| Message Endpoint | How does an application connect to a messaging channel to send and receive messages? |
Messaging Channels Image Added
| Point to Point Channel | How can the caller be sure that exactly one receiver will receive the document or perform the call? |  Image Added
| Publish Subscribe Channel | How can the sender broadcast an event to all interested receivers? |  Image Added
| Dead Letter Channel | What will the messaging system do with a message it cannot deliver? |  Image Added
| Guaranteed Delivery | How can the sender make sure that a message will be delivered, even if the messaging system fails? |  Image Added
| Message Bus | What is an architecture that enables separate applications to work together, but in a de-coupled fashion such that applications can be easily added or removed without affecting the others? |
Message Construction Image Added
| Event Message | How can messaging be used to transmit events from one application to another? |  Image Added
| Request Reply | When an application sends a message, how can it get a response from the receiver? |  Image Added
| Correlation Identifier | How does a requestor that has received a reply know which request this is the reply for? |  Image Added
| Return Address | How does a replier know where to send the reply? |
Message RoutingImage Added |
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| Content Based Router | How do we handle a situation where the implementation of a single logical function (e.g., inventory check) is spread across multiple physical systems? |
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Message Filter | How can a component avoid receiving uninteresting messages? |  Image Added
| Dynamic Router | How can you avoid the dependency of the router on all possible destinations while maintaining its efficiency? |  Image Added
| Recipient List | How do we route a message to a list of (static or dynamically) specified recipients? |  Image Added
| Splitter | How can we process a message if it contains multiple elements, each of which may have to be processed in a different way? |  Image Added
| Aggregator | How do we combine the results of individual, but related messages so that they can be processed as a whole? |  Image Added
| Resequencer | How can we get a stream of related but out-of-sequence messages back into the correct order? |  Image Added
| Composed Message Processor | How can you maintain the overall message flow when processing a message consisting of multiple elements, each of which may require different processing? |  Image Added
| Scatter-Gather | How do you maintain the overall message flow when a message needs to be sent to multiple recipients, each of which may send a reply? |  Image Added
| Routing Slip | How do we route a message consecutively through a series of processing steps when the sequence of steps is not known at design-time and may vary for each message? | Image Added | Throttler | How can I throttle messages to ensure that a specific endpoint does not get overloaded, or we don't exceed an agreed SLA with some external service? | Image Added | Sampling | How can I sample one message out of many in a given period to avoid downstream route does not get overloaded? | Image Added | Delayer | How can I delay the sending of a message? | Image Added | Load Balancer | How can I balance load across a number of endpoints? | | | Hystrix | To use Hystrix Circuit Breaker when calling an external service. | | | Service Call | To call a remote service in a distributed system where the service is looked up from a service registry of some sorts. | Image Added | Multicast | How can I route a message to a number of endpoints at the same time? | Image Added | Loop | How can I repeat processing a message in a loop? |
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| Content Enricher | How do we communicate with another system if the message originator does not have all the required data items available? |  Image Added
| Content Filter | How do you simplify dealing with a large message, when you are interested only in a few data items? |  Image Added
| Claim Check | How can we reduce the data volume of message sent across the system without sacrificing information content? |  Image Added
| Normalizer | How do you process messages that are semantically equivalent, but arrive in a different format? | Image Added | Sort | How can I sort the body of a message? | | | Script |
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System Management
How do I execute a script which may not change the message? | Image Added | Validate | How can I validate a message? |
Messaging EndpointsImage Added | Messaging Mapper | How do you move data between domain objects and the messaging infrastructure while keeping the two independent of each other? |  Image Added
| Event Driven Consumer | How can an application automatically consume messages as they become available? |  Image Added
| Polling Consumer | How can an application consume a message when the application is ready? |  Image Added
| Competing Consumers | How can a messaging client process multiple messages concurrently? |  Image Added
| Message Dispatcher | How can multiple consumers on a single channel coordinate their message processing? |  Image Added
| Selective Consumer | How can a message consumer select which messages it wishes to receive? |  Image Added
| Durable Subscriber | How can a subscriber avoid missing messages while it's not listening for them? | Image Added | Idempotent Consumer | How can a message receiver deal with duplicate messages? |  Image Added
| Transactional Client | How can a client control its transactions with the messaging system? |  Image Added
| Messaging Gateway | How do you encapsulate access to the messaging system from the rest of the application? |  Image Added
| Service Activator | How can an application design a service to be invoked both via various messaging technologies and via non-messaging techniques? |
System Management Image Added
| ControlBus | How can we effectively administer a messaging system that is distributed across multiple platforms and a wide geographic area? |  Image Added
| Detour | How can you route a message through intermediate steps to perform validation, testing or debugging functions? |  Image Added
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| Wire Tap | How do you inspect messages that travel on a point-to-point channel? | Image Added | Message History | How can we effectively analyze and debug the flow of messages in a loosely coupled system? | Image Added | Log | How can I log processing a message? |
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