Which user can accept which workflow task depends on several conditions. First of all there is an access rights system in place where groups are granted certain rights (that is read, write, accept, complete, cancel) on a task. In addition, for publication workflows there exist performer policies that determine which users have the required access rights on the workflow's contents. For more details on these fundamental mechanisms, see the Workflow Manual.

The special case of assignees is covered because it also requires a Studio client configuration. If a task is an assignment task, the user of the predecessor task can specify assignees for the task. Assignees can be multiple users and groups. Only assigned users or members of assigned groups can then carry out the task. Currently, assignees are only supported for publication workflows out of the box.

The following example shows how the Approve and Publish tasks of the Studio-Two-Step-Publication process definition are defined as assignment tasks.

<Workflow>
  <Process name="..." startTask="...">
    <!-- ... -->

    <UserTask name="Approve"
              description="studio-three-step-publication-approve-task"
              successor="PublishOrCompose" reexecutable="true">
      <Performers policyClass="com.coremedia.cap.workflow.plugin.AssignableResourcePermissionsPerformersPolicy"
                  assignedUsersVariable="assignedUsers_Approve"
                  assignedGroupsVariable="assignedGroups_Approve"
                  rights="approve, publish"/>
      <Rights>
        <Grant group="administratoren" rights="read, accept, cancel, delegate, reject"/>
        <Grant group="approver-role" rights="read, accept, cancel, delegate, reject"/>
      </Rights>
      <Assignment>
        <Reads variable="assignedUsers_Approve"/>
        <Reads variable="assignedGroups_Approve"/>
        <Writes variable="assignedUsers_Publish"/>
        <Writes variable="assignedGroups_Publish"/>
        <!-- ... -->
      </Assignment>
      <!-- ... -->
    </UserTask>

    <UserTask name="Approve"
              description="studio-three-step-publication-approve-task"
              successor="ApproveOrDoPublish" reexecutable="true">
      <Performers policyClass="com.coremedia.cap.workflow.plugin.AssignableResourcePermissionsPerformersPolicy"
                  assignedUsersVariable="assignedUsers_Publish"
                  assignedGroupsVariable="assignedGroups_Publish"
                  rights="publish"/>
      <Rights>
        <Grant group="administratoren" rights="read, accept, cancel, delegate, reject"/>
        <Grant group="publisher-role" rights="read, accept, cancel, delegate, reject"/>
      </Rights>
      <Assignment>
        <Reads variable="assignedUsers_Publish"/>
        <Reads variable="assignedGroups_Publish"/>
        <!-- ... -->
      </Assignment>
      <!-- ... -->
    </UserTask>
  </Process>
</Workflow>

In order to make a task an assignment task, the AssignableResourcePermissionsPerformersPolicy has to be set as the performers policy of the task. In addition, this policy needs to be configured with the two parameters assignedUsersVariable and assignedGroupsVariable. The values for both parameters need to be process variables and they need to follow the exact naming pattern of assignedUsers_{$taskName} and assignedGroups_{$taskName}. In the example, one can also see that the Approve task reads the assignedUsers_Approve and assignedGroups_Approve variables and writes the assignedUsers_Publish and assignedGroups_Publish variables.

For the Studio client, configuring a workflow step as an assignment task is very easy as shown in Example 9.118, “Workflow steps configuration for the built-in 2-step publication workflow ”: In the WorkflowTransition definition for the Compose task, the WorkflowStep definition for Approve has the parameter isAssignmentTask set.

To conclude, the WorkflowTransition#isAssignmentTask configurations for the Studio client must match the AssignableResourcePermissionsPerformersPolicy configurations of the process definition on the workflow server.