Is it possible to delegate a task to another group or set of groups in jBPM6 ?

Diagnostic Steps

• Even going through the source code of jBPM6 one can see that it is also adhering to the same definition provided in the WS-HT specification, in perspective of Task delegation feature. Here is a gist of the code flow for reference.

package org.jbpm.services.task.impl.command;
...
import org.jbpm.services.task.commands.DelegateTaskCommand;
...
public class CommandBasedTaskService implements InternalTaskService, EventService<TaskLifeCycleEventListener> {

    private CommandService executor;
    private TaskEventSupport taskEventSupport;

    public CommandBasedTaskService(CommandService executor, TaskEventSupport taskEventSupport) {        
        this.executor = executor;
        this.taskEventSupport = taskEventSupport;
    }

    @Override
    public <T> T execute(Command<T> command) {
        return executor.execute(command);
    }
    ...
    public void delegate(long taskId, String userId, String targetUserId) {
        executor.execute(new DelegateTaskCommand(taskId, userId, targetUserId));
    }
        ...

This calls for org.jbpm.services.task.commands.DelegateTaskCommand class's DelegateTaskCommand(long,String,String) constructor.

package org.jbpm.services.task.commands;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;

import org.kie.internal.command.Context;

/**
*Operation.Delegate 
        : [ new OperationCommand().{ 
                status = [ Status.Ready ],
                allowed = [ Allowed.PotentialOwner, Allowed.BusinessAdministrator  ],
                addTargetUserToPotentialOwners = true,            
                newStatus = Status.Ready,
                exec = Operation.Claim
            },
            new OperationCommand().{ 
                status = [ Status.Reserved, Status.InProgress ],
                allowed = [ Allowed.Owner, Allowed.BusinessAdministrator ],
                addTargetUserToPotentialOwners = true,                         
                newStatus = Status.Ready,
                exec = Operation.Claim
            } ],
 */
@XmlRootElement(name="delegate-task-command")
@XmlAccessorType(XmlAccessType.NONE)
public class DelegateTaskCommand extends UserGroupCallbackTaskCommand<Void> {

    /**
     * 
     */
    private static final long serialVersionUID = 5656199063761548979L;

    public DelegateTaskCommand() {
    }

    public DelegateTaskCommand(long taskId, String userId, String targetEntityId) {
        this.taskId = taskId;
        this.userId = userId;
        this.targetEntityId = targetEntityId;
    }

    public Void execute(Context cntxt) {
        TaskContext context = (TaskContext) cntxt;
        doCallbackUserOperation(userId, context);
        doCallbackUserOperation(targetEntityId, context);
        doUserGroupCallbackOperation(userId, null, context);
        context.getTaskInstanceService().delegate(taskId, userId, targetEntityId);
        return null;

    }
}

Internally the execute(..) method calls the TaskInstanceServiceImpl.delegate(..) method.

public class TaskInstanceServiceImpl implements TaskInstanceService {
...
    private LifeCycleManager lifeCycleManager;
...

    public void delegate(long taskId, String userId, String targetUserId) {
        lifeCycleManager.taskOperation(Operation.Delegate, taskId, userId, targetUserId, null, null);
    }
...

Looking into the signature of LifeCycleManager.taskOperation(...) , it says that the last parameter in the taskOperation method accepts List of Groups, which in case of delegation is null.

package org.jbpm.services.task.internals.lifecycle;
import java.util.List;
import java.util.Map;

import org.kie.internal.task.api.model.Operation;
import org.kie.internal.task.exception.TaskException;

/**
 *
 */
public interface LifeCycleManager {
    public void taskOperation(final Operation operation, final long taskId, final String userId,
                              final String targetEntityId, final Map<String, Object> data,
                              List<String> groupIds) throws TaskException;
}

Hence, as it is visible the delegation operation only performs the assignment of task to a user only not for groups.