public String updateVariable() {
if (this.variableName != null) {
JbpmContext jbpmContext = JbpmContext.getCurrentJbpmContext();
GraphSession graphSession = jbpmContext.getGraphSession();
ProcessInstance processInstance = graphSession.loadProcessInstance(this.id);
if (this.variableValue != null) {
processInstance.getContextInstance().setVariable(this.variableName, this.variableValue);
} else {
processInstance.getContextInstance().deleteVariable(this.variableName);
}