String outputDataCollection = getPropertyValueAsString(PROPERTY_MULTIINSTANCE_OUTPUT_COLLECTION, elementNode);
String outputDataItem = getPropertyValueAsString(PROPERTY_MULTIINSTANCE_OUTPUT_ITEM, elementNode);
String completeExpression = getPropertyValueAsString(PROPERTY_MULTIINSTANCE_CONDITION, elementNode);
//输出变量
DataOutput dataOutput = Bpmn2Factory.eINSTANCE.createDataOutput();
Expression dataOutputExpression = FixFlowFactory.eINSTANCE.createExpression();
dataOutputExpression.setName(outputDataItem);
dataOutputExpression.setValue(outputDataItem);
BpmnModelUtil.addExtensionElement(dataOutput, FixFlowPackage.Literals.RESOURCE_FILTER__EXPRESSION, dataOutputExpression);
newLoopCharacteristics.setOutputDataItem(dataOutput);