org.activiti.engine.impl.bpmn.data
接口 
FieldBaseStructureDefinition
StructureDefinition
StructureInstance
 
AbstractDataAssociation
Assignment
ClassStructureDefinition
Data
DataRef
FieldBaseStructureInstance
IOSpecification
ItemDefinition
ItemInstance
PrimitiveStructureDefinition
PrimitiveStructureInstance
SimpleDataInputAssociation
SimpleStructureDefinition
TransformationDataOutputAssociation
枚举 
ItemKind