jBPM retrigger last WorkItem command

gistfile1.java

package com.mycompany.sample.jbpm.command;

import org.drools.core.command.impl.GenericCommand;
import org.drools.core.command.impl.KnowledgeCommandContext;
import org.drools.core.process.instance.WorkItem;
import org.jbpm.workflow.instance.node.WorkItemNodeInstance;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.process.NodeInstance;
import org.kie.api.runtime.process.WorkflowProcessInstance;
import org.kie.internal.command.Context;
import com.mycompany.sample.jbpm.dto.AppSession;

import java.util.Collection;
import java.util.NoSuchElementException;

public class ReTriggerWorkItemCommand implements GenericCommand<WorkItem> {

    private final Long processInstanceId;

    public ReTriggerWorkItemCommand(Long processInstanceId) {
        this.processInstanceId = processInstanceId;
    }

    public ReTriggerWorkItemCommand(AppSession appSession) {
        if (appSession == null) {
            throw new IllegalArgumentException("AppSession can not be null");
        }
        this.processInstanceId = appSession.getProcessInstanceId();
    }

    @Override
    public WorkItem execute(Context context) {
        WorkItem workItem = null;
        KieSession ksession = ((KnowledgeCommandContext) context).getKieSession();
        WorkflowProcessInstance pi = (WorkflowProcessInstance) ksession.getProcessInstance(processInstanceId);
        if (pi != null) {
            Collection<NodeInstance> nodes = pi.getNodeInstances();

            try {
                NodeInstance nodeInstance = nodes.iterator().next();
                WorkItemNodeInstance workItemNodeInstance = (WorkItemNodeInstance) nodeInstance;
                workItem = workItemNodeInstance.getWorkItem();

                switch(workItem.getState()) {
                    case WorkItem.COMPLETED:
                        workItemNodeInstance.workItemCompleted(workItem);
                        break;
                    case WorkItem.ABORTED:
                        workItemNodeInstance.workItemAborted(workItem);
                        break;
                    default:
                        workItemNodeInstance.retrigger(true);
                }
            } catch (NoSuchElementException nsee) {
                /**
                 * this is about retrieving the currently active
                 * node. if it fails the process is probably
                 * isn't working but the execution status
                 * remained active for some reason. This makes
                 * the client to check for the currently active
                 * node constantly.
                 */
            }
        }
        return workItem;
    }
}