StructureDefinition structure = null;
try {
// it is a class
Class< ? > classStructure = ReflectUtil.loadClass(itemDefinitionElement.getStructureRef());
structure = new ClassStructureDefinition(classStructure);
} catch (ActivitiException e) {
// it is a reference to a different structure
structure = this.structures.get(itemDefinitionElement.getStructureRef());
}