Map Event Formatter

Map event formatter converts the events coming from Siddhi to Map events according to the output mapping configurations. Here, each output event is considered as a map object. 

Y ou can configure through the management console as explained below or by manually adding an XML file as explained in step 5.

1. Start the CEP, log in to its management console, select Event Formatters and click Add Event Formatter .
2. Enter details in the form that appears and click the Add Event Formatter button at the end of the form. For example,
   The fields in the above configuration are as follows:
   
   
   • Event Formatter Name : Property to uniquely identify an event formatter configuration
   • Event Stream (marked as 1 in the screenshot) : Select an event stream (stream name with version) to listen for events.
   • Stream Attributes : Based on the event stream selected earlier, this shows what the attributes available in the stream are. This field is only for reference.
   • Output Event Adaptor Name (marked as 2 in the screenshot) : Select the event adaptor used to publish events from the CEP. This drop-down list shows the output event adaptors already created.
   • Output Mapping Type (marked as 3 the screenshot) : Select map mapping type. This drop-down list is populated based on the event adaptor selected earlier. It lists only the mapping types supported by a particular event adaptor. Some event adaptors support multiple types of mappings.
     

     Map Mapping

     Map event is simply a map object, a <key,value> pair. Name is used as a key in the event and the actual value is used as value attribute.

     • Name : The attribute name to which the event data is mapped when creating the output Map Event
     • Value Of : The attribute/property name from which the data element is mapped
   • Stream Name/Version : Since you selected a JMS type event adaptor here, you need a destination to send events to, from the CEP.
3. After an event formatter is successfully created, you can change its configuration and redeploy it. To do this, click the Edit link associated with it.
4. An XML based editor opens allowing you to edit the event builder configuration from the UI itself, without having to edit the file in the file system. Do your modifications and click Update.

5. Alternatively, you can specify an event formatter configuration using an XML file and save it in <PRODUCT_HOME>/repository/deployment/server/eventformatters directory, which is the event formatter deployment directory. Since hot deployment is enabled, you can simply add/remove files to deploy/undeploy from the server.
   
   Create the XML file with the following Map mapping event formatter configurations. Event formatter implementation must start with <eventformatter> root element as in the example below.

   <eventFormatter name="StatisticsFormatter" xmlns="http://wso2.org/carbon/eventformatter">
     <from streamName="statisticsStream" version="1.0.0"/>
     <mapping type="map">
       <property>
         <from name="ipAddress"/>
         <to name="ipAddress"/>
       </property>
       <property>
         <from name="user"/>
         <to name="username"/>
       </property>
     </mapping>
     <to eventAdaptorName="jmsTransportAdaptor" eventAdaptorType="jms">
       <property name="transport.jms.Destination">statisticInfo</property>
     </to>
   </eventFormatter>