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MESSAGE ORIENTED MESSAGE ORIENTED MODEL (MOM)MODEL (MOM)
Slide 2
Message-Oriented Model (MOM)Message-Oriented Model (MOM)
Slide 3
Elements of the MOMElements of the MOM
• Correlation• Intermediary• Message• Message envelope• Message exchange pattern• Message header
• Correlation• Intermediary• Message• Message envelope• Message exchange pattern• Message header
Slide 4
Elements of MOM (Cont’d)Elements of MOM (Cont’d)
• Message description language
• Message identifier
• Message path
• Message recipient
• Message sender
• Message description language
• Message identifier
• Message path
• Message recipient
• Message sender
Slide 5
Elements of MOM (Cont’d)Elements of MOM (Cont’d)
• Message transport
• Reliable messaging
• Message transport
• Reliable messaging
Slide 6
CorrelationCorrelation
• A means of associating a message with a context
– The message received is the one expected by this message recipient
Usually accomplished with a message identifier
• A means of associating a message with a context
– The message received is the one expected by this message recipient
Usually accomplished with a message identifier
Slide 7
IntermediaryIntermediary
• An agent that is both a message recipient and a message sender
• May have partial access to the message it processes
• Forwards the message along the message path
• An agent that is both a message recipient and a message sender
• May have partial access to the message it processes
• Forwards the message along the message path
Slide 8
MessageMessage
• A unit of data sent from one agent to another
• May be part of a message exchange pattern
• Described by a message description language
• A unit of data sent from one agent to another
• May be part of a message exchange pattern
• Described by a message description language
Slide 9
Message (Cont’d)Message (Cont’d)
• Has a message sender
• Has a message identifier
• May have a message content
• Has zero or more message headers
• May have a message envelope
• Has a message sender
• Has a message identifier
• May have a message content
• Has zero or more message headers
• May have a message envelope
Slide 10
Message EnvelopeMessage Envelope
• Is meta-data associated with a message
• Contains address information about intended recipients
• Contains the body of the message
• Is meta-data associated with a message
• Contains address information about intended recipients
• Contains the body of the message
Slide 11
Message Exchange Pattern (MEP)Message Exchange Pattern (MEP)
• A template describing a generic pattern for the exchange of messages between agents
• A feature of the architecture• Should have a unique identifier• Is the life cycle of a message exchange
• A template describing a generic pattern for the exchange of messages between agents
• A feature of the architecture• Should have a unique identifier• Is the life cycle of a message exchange
Slide 12
MEP (Cont’d)MEP (Cont’d)
• Describes the temporal and causal relationships, if any, of multiple messages exchanged in conformance with the pattern
• Describes the normal and abnormal termination of any message exchange conforming to the pattern
• Realizes the message correlation• Describes a service invocation• Must be mapped to a protocol
• Describes the temporal and causal relationships, if any, of multiple messages exchanged in conformance with the pattern
• Describes the normal and abnormal termination of any message exchange conforming to the pattern
• Realizes the message correlation• Describes a service invocation• Must be mapped to a protocol
Slide 13
Message HeaderMessage Header
• Is part of a message• May contain routing information• May contain message security info• May contain message orchestration
information• May contain message transaction context
• Is part of a message• May contain routing information• May contain message security info• May contain message orchestration
information• May contain message transaction context
Slide 14
Message OrchestrationMessage Orchestration
• Encapsulates and executes business process logic
• Can integrate with other applications to retrieve additional data
• Can invoke broker component• Can use application logic• Can reject data that fails validation
• Encapsulates and executes business process logic
• Can integrate with other applications to retrieve additional data
• Can invoke broker component• Can use application logic• Can reject data that fails validation
Slide 15
Message Description LanguageMessage Description Language
• Describes the structure of the message
– Types of the elements– How recipients and senders are identified– Which headers are associated with the
message
• Describes the structure of the message
– Types of the elements– How recipients and senders are identified– Which headers are associated with the
message
Slide 16
Message IdentifierMessage Identifier
• A field that uniquely identifies a message• Allows messages to be correlated within an
extended transaction• Supports message reliability• Supports message management and
accountability of services
• A field that uniquely identifies a message• Allows messages to be correlated within an
extended transaction• Supports message reliability• Supports message management and
accountability of services
Slide 17
Message PathMessage Path
• Is a sequence of agents
• Contains zero or more intermediaries
• Has a unique originator and recipient
• Message may be processed by a number of interdediaries
• Is a sequence of agents
• Contains zero or more intermediaries
• Has a unique originator and recipient
• Message may be processed by a number of interdediaries
Slide 18
Message RecipientMessage Recipient
• A agent that receives a message
• May be an intermediary
• Has an agent identifier
• Agent identifier is not used for broadcast messages
• A agent that receives a message
• May be an intermediary
• Has an agent identifier
• Agent identifier is not used for broadcast messages
Slide 19
Message SenderMessage Sender
• The agent that transmits a message• Sender may be an intermediary• May be identified by its agent identifier
in the message envelope• Identifier not present in anonymous
interactions
• The agent that transmits a message• Sender may be an intermediary• May be identified by its agent identifier
in the message envelope• Identifier not present in anonymous
interactions
Slide 20
Message TransportMessage Transport
• A mechanism that may be used by agents to deliver a message
• Examples:– HTTP over TCP– SOAP transport– Message-oriented middleware
• A mechanism that may be used by agents to deliver a message
• Examples:– HTTP over TCP– SOAP transport– Message-oriented middleware
Slide 21
Message Transport (Cont’d)Message Transport (Cont’d)
• Responsibilities:– Timeliness of transport– Privacy– Reliability
• Responsibilities:– Timeliness of transport– Privacy– Reliability
Slide 22
Reliable MessagingReliable Messaging
• A key infrastructure-level component of reliability
• Realized by a combination of message acknowledgement and correlation
• A key infrastructure-level component of reliability
• Realized by a combination of message acknowledgement and correlation