Publish Event Mediator

The Publish Event mediator constructs events and publishes them to different systems such as BAM and CEP.

The Publish Event mediator is a content-aware mediator.

Syntax

<publishEvent [eventSink="string"] [streamName="string"] [streamVersion="string">
    <attributes>
        <meta>
            <attribute name="string" (value="literal" | expression="[XPath|json-eval(JSON Path)]") [type=string|integer|boolean|double|float|long]/>*
        </meta>
        <correlation>
            <attribute name="string" (value="literal" | expression="[XPath|json-eval(JSON Path)]") [type=string|integer|boolean|double|float|long]/>*
        </correlation>
        <payload>
            <attribute name="string" (value="literal" | expression="[XPath|json-eval(JSON Path)]") [type=string|integer|boolean|double|float|long]/>*
        </payload>
        <arbitrary>
            <attribute name="string" (value="literal" | expression="[XPath|json-eval(JSON Path)]") [type=string|integer|boolean|double|float|long]/>*
        </arbitrary>
    </attributes>
</publishEvent>

UI Configuration

Parameters that can be configured for the Publish Event mediator are as follows.

Parameter Name	Description
Stream Name	The name of the stream to be used for sending data.
Stream Version	The version of the stream to be used for sending data.
EventSink	The name of the event sink to which the events should be published.

You can add the following four types of attributes to a Publish Event mediator configuration.

Meta Attributes: The list of attributes which are included in the Meta section of the event.
Correlated Attributes: The list of attributes that are included in the Correlated section of the event.
Payload Attributes: The list of attributes that are included in the Payload section of the event.
Arbitrary Attributes: The list of attributes that are included in the Arbitrary section of the event.

The parameters that are available to configure an individual attribute are as follows.

Parameter Name	Description
Attribute Name	The name of the attribute.
Attribute Value	This parameter specifies whether the value of the attribute should be a static value or an expression. Value: Select this if the attribute value should be a static value, and enter the relevant value in the Value/Expression parameter. Expression: Select this if the attribute value should be evaluated via an XPath expression, and enter the relevant expression in the Value/Expression parameter.
Value/Expression	The value of the attribute. You can enter a static value, or an expression to evaluate the value depending on the selection made in the Attribute Value parameter.
Type	The data type of the attribute.
Action	Click Delete in the relevant row to delete an attribute.

Example

In this configuration, the Publish Event mediator uses four attributes to extract information from the ESB. This information is published in an event sink in WSO2 BAM named bam_event_sink.

<publishEvent>
  <eventSink>bam_event_sink</eventSink>
  <streamName>stream_88</streamName>
  <streamVersion>1.1.2</streamVersion>
  <attributes>
     <meta>
        <attribute name="http_method"
                   type="STRING"
                   defaultValue=""
                   expression="get-property('axis2', 'HTTP_METHOD')"/>
        <attribute name="destination"
                   type="STRING"
                   defaultValue=""
                   expression="get-property('To')"/>
     </meta>
     <correlation>
        <attribute name="date"
                   type="STRING"
                   defaultValue=""
                   expression="get-property('SYSTEM_DATE')"/>
     </correlation>
     <payload>
        <attribute xmlns:m0="http://services.samples"
                   name="symbol"
                   type="STRING"
                   defaultValue=""
                   expression="$body/m0:getQuote/m0:request/m0:symbol"/>
     </payload>
  </attributes>
</publishEvent>