Enterprise Integration Patterns Flashcards
Message Channel
How does one application communicate with another using messaging?
How can two applications connected by a message channel exchange a piece of information?
Message
How can we perform complex processing on a message while maintaining independence and flexibility?
Pipes and Filters
How can you decouple individual processing steps so that messages can be passed to different filters depending on a set of conditions?
Message Router
How can systems using different data formats communicate with each other using messaging?
Message Translator
How does an application connect to a messaging channel to send and receive messages?
Message Endpoint
How can the caller be sure that exactly one receiver will receive the document or perform the call?
Point-to-Point Channel
How can the sender broadcast an event to all interested receivers?
Publish-Subscribe Channel
How can the application send a data item such that the receiver will know how to process it?
Datatype Channel
How can a messaging receiver gracefully handle receiving a message that makes no sense?
Invalid Message Channel
What will the messaging system do with a message it cannot deliver?
Dead Letter Channel
How can the sender make sure that a message will be delivered even if the messaging system fails?
Guaranteed Delivery
How can you connect an application to the messaging system so that it can send and receive messages?
Channel Adapter
How can multiple messaging systems be connected so that messages available on one are also available on the others?
Messaging Bridge
What is an architecture that enables separate applications to work together but in a decoupled fashion such that applications can be easily added or removed without affecting the others?
Message Bus
How can messaging be used to invoke a procedure in another application?
Command Message
How can messaging be used to transfer data between applications?
Document Message
How can messaging be used to transmit events from one application to another?
Event Message
When an application sends a message how can it get a response from the receiver?
Request-Reply
How does a replier know where to send the reply?
Return Address
How does a requestor that has received a reply know which request this is the reply for?
Correlation Identifier
How can messaging transmit an arbitrarily large amount of data?
Message Sequence
How can a sender indicate when a message should be considered stale and thus shouldn’t be processed?
Message Expiration
How can a message’s data format be designed to allow for possible future changes?
The format indicator enables the sender to tell the receiver the format of the message. This way, a receiver expecting several possible formats knows which one a message is using and therefore how to interpret the message’s contents.
There are three main alternatives for implementing a format indicator:
Version Number – A number or string that that uniquely identifies the format. Both the sender and receiver must agree on which format is designated by a particular indicator.
Foreign Key – A unique ID—such as a filename, a database row key, a home primary key, or an Internet URL—that specifies a format document. The sender and receiver must agree on the mapping of keys to documents, and the format of the schema document.
Format Document – A schema that describes the data format. The schema document does not have to be retrieved via a foreign key or inferred from a version number, it is embedded in the message. The sender and the receiver must agree on the format of the schema.