CREATE BUSINESS EVENT SERVICE

Synopsis

CREATE [ OR MODIFY ] BUSINESS EVENT SERVICE module.Name
(
    ServiceName: 'service_name',
    EventNamePrefix: 'prefix'
)
{
    MESSAGE MessageName ( attr: Type [, ...] ) PUBLISH | SUBSCRIBE
        [ ENTITY module.Entity ] ;
    [ ... ]
}

Description

Creates a business event service that defines one or more messages for event-driven communication between applications.

Each message has a name, a set of typed attributes, and an operation mode (PUBLISH or SUBSCRIBE). A publishing message means this application sends events of that type. A subscribing message means this application receives and handles events of that type.

The OR MODIFY option updates the existing service in-place, preserving its UUID so that references from other documents remain valid. OR REPLACE is also accepted as a synonym.

Service Properties

The service declaration includes two required properties:

ServiceName – The logical service name used for event routing on the Mendix Business Events broker.
EventNamePrefix – A prefix prepended to message names to form the fully qualified event name. Can be empty ('').

Message Attributes

Each message defines zero or more attributes with the following supported types:

Type	Description
`String`	Text value
`Integer`	32-bit integer
`Long`	64-bit integer
`Boolean`	True/false
`DateTime`	Date and time
`Decimal`	Arbitrary-precision decimal

Entity Mapping

The optional ENTITY clause on a message links the message to a Mendix entity. For SUBSCRIBE messages, incoming events are mapped to instances of this entity. For PUBLISH messages, entity instances are serialized into outgoing events.

Parameters

module.Name: Qualified name of the business event service (Module.ServiceName).
ServiceName: 'service_name': The logical service identifier used by the Business Events broker.
EventNamePrefix: 'prefix': A prefix for event names. Use an empty string ('') for no prefix.
MESSAGE MessageName: The name of a message within the service.
attr: Type: An attribute definition within a message. Multiple attributes are comma-separated.
PUBLISH: This application publishes (sends) this message type.
SUBSCRIBE: This application subscribes to (receives) this message type.
ENTITY module.Entity: Optional entity linked to the message for data mapping.

Examples

Create a service that publishes order events:

CREATE BUSINESS EVENT SERVICE Shop.OrderEvents
(
    ServiceName: 'com.example.shop.orders',
    EventNamePrefix: 'shop'
)
{
    MESSAGE OrderCreated (OrderId: Long, CustomerName: String, Total: Decimal) PUBLISH
        ENTITY Shop.Order;
    MESSAGE OrderShipped (OrderId: Long, TrackingNumber: String) PUBLISH
        ENTITY Shop.Shipment;
};

Create a service that subscribes to external events:

CREATE BUSINESS EVENT SERVICE Inventory.StockUpdates
(
    ServiceName: 'com.example.warehouse.stock',
    EventNamePrefix: ''
)
{
    MESSAGE StockChanged (ProductId: Long, NewQuantity: Integer) SUBSCRIBE
        ENTITY Inventory.StockLevel;
};

Replace an existing service:

CREATE OR REPLACE BUSINESS EVENT SERVICE Shop.OrderEvents
(
    ServiceName: 'com.example.shop.orders',
    EventNamePrefix: 'shop'
)
{
    MESSAGE OrderCreated (OrderId: Long, CustomerName: String, Total: Decimal) PUBLISH;
    MESSAGE OrderCancelled (OrderId: Long, Reason: String) PUBLISH;
};

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