Sequence declaration reference

Sequencing is declared in a YAML descriptor, by default loaded from classpath:/messaging/jeap-sequential-inbox.yml (override with jeap.messaging.sequential-inbox.config-location). The file has two top-level keys: an optional subTypeResolvers map and a list of sequences.

Sequence

Attribute	Cardinality	Description	Example
name	Required	Name of the sequence (used in logs, the REST API and the sequence instance rows)	OrderSequence
retentionPeriod	Required	How long a sequence instance is retained, as a Duration; drives expiry and housekeeping	24h
messages	Required	The list of SequencedMessageType entries that belong to the sequence

SequencedMessageType

Attribute	Cardinality	Description	Example
type	Required	The jEAP message type name (the Avro message simple class name)	JmeOrderCreatedEvent
subType	Optional	Subtype for fine-grained sequencing of a generic message type. Resolved by a SubTypeResolver; must be a value of the resolver's Java Enum	STOCK_AVAILABLE
topic	Optional	Topic to consume the message from, if different from the default	my-topic
clusterName	Optional	Kafka cluster of the topic, if different from the default cluster	aws
contextIdExtractor	Required	Fully-qualified class name implementing ContextIdExtractor; returns the contextId grouping messages into one instance (null = not sequenceable)	ch.admin.bit.example.OrderIdExtractor
messageFilter	Optional	Fully-qualified class name implementing MessageFilter; shouldSequence returning false means the message bypasses the inbox and is handled immediately	ch.admin.bit.example.OrderCreatedEventFilter
releaseCondition	Optional	The predecessor(s) that must be processed before this message is released. No condition means the message can be released as soon as it arrives

Release conditions

A release condition references predecessors by their qualified name (type, or type.subType when a subtype is used). Conditions can be nested with and and or.

# single predecessor
releaseCondition:
  predecessor: JmeOrderCreatedEvent

# all of several predecessors
releaseCondition:
  and:
    - predecessor: JmeOrderValidatedEvent.STOCK_AVAILABLE
    - predecessor: JmeOrderValidatedEvent.CUSTOMER_CREDIT_CHECKED
    - predecessor: JmeOrderPreparedEvent

# any one of several predecessors
releaseCondition:
  or:
    - predecessor: JmeOrderShippedEvent
    - predecessor: JmeOrderOtherEvent

subTypeResolvers

When one Avro message type represents several business events, map it to a SubTypeResolver so the inbox can distinguish the subtypes. The resolver returns an Enum; every enum value must be declared as a subType in the sequence, and every subType must be a valid enum value.

subTypeResolvers:
  JmeOrderValidatedEvent: ch.admin.bit.example.OrderValidatedEventSubTypeResolver

Full example

subTypeResolvers:
  JmeOrderValidatedEvent: ch.admin.bit.example.OrderValidatedEventSubTypeResolver

sequences:
  - name: OrderSequence
    retentionPeriod: 24h
    messages:
      - type: JmeOrderCreatedEvent
        contextIdExtractor: ch.admin.bit.example.OrderIdExtractor
        messageFilter: ch.admin.bit.example.OrderCreatedEventFilter

      - type: JmeOrderValidatedEvent
        subType: STOCK_AVAILABLE
        contextIdExtractor: ch.admin.bit.example.OrderIdExtractor
        releaseCondition:
          predecessor: JmeOrderCreatedEvent

      - type: JmeOrderValidatedEvent
        subType: CUSTOMER_CREDIT_CHECKED
        contextIdExtractor: ch.admin.bit.example.OrderIdExtractor
        releaseCondition:
          predecessor: JmeOrderCreatedEvent

      - type: JmeOrderShippedEvent
        contextIdExtractor: ch.admin.bit.example.OrderIdExtractor
        releaseCondition:
          and:
            - predecessor: JmeOrderValidatedEvent.STOCK_AVAILABLE
            - predecessor: JmeOrderValidatedEvent.CUSTOMER_CREDIT_CHECKED

Related

• Getting started
• How sequencing works
• Configuration reference
• jeap-messaging-sequential-inbox