Placeholder may be used in some fields of tasks. They are especially useful for email tasks, where you can generate the content of email according to context variables.

Note: In most cases, you can avoid this by using email templates (See E-mail task for details)

These fields are preprocessed by Apache Velocity templating engine. See the Velocity project URL for syntax description http://velocity.apache.org/.

There are several context variables, which you can use in placeholders and even for creating loops and conditions.

Some of them may be empty depending on the type of the event. For example, if a task is processed because of a graph event, then run and sandbox variables contain related data, otherwise they are empty.

#if (${tracking})
<table border="1" cellpadding="2" cellspacing="0">
#foreach ($phase in $tracking.trackingPhases)
<tr><td>phase: ${phase.phaseNum}</td>
    <td>${phase.executionTime} ms</td>
    <td></td><td></td><td></td></tr>
   #foreach ($node in $phase.trackingNodes)
      <tr><td>${node.nodeName}</td>
          <td>${node.result}</td>
          <td></td><td></td><td></td></tr>
      #foreach ($port in $node.trackingPorts)
         <tr><td></td><td></td>
             <td>${port.type}:${port.index}</td>
             <td>${port.totalBytes} B</td>
             <td>${port.totalRows} rows</td></tr>
      #end
   #end
#end
</table>
#end
}