CREATE BUSINESS EVENT SERVICE

Synopsis

CREATE [ OR REPLACE ] 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 REPLACE option drops any existing service with the same name before creating the new one.

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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