JAXB2 jaxb-api.jar jaxb-xjc.jar jaxb-impl.jar activation.jar

-- Ordering of properties/fields -- Synopsis This sample demonstrates the use of annotations @XmlAccessorOrder and @XmlType.propOrder to dictate the order in which XML content is marshalled/unmarshaled by a Java type. -- Details Java to Schema maps a JavaBean's properties and fields to an XML Schema type. The class elements are mapped to either an XML Schema complex type or an XML Schema simple type. The default element order for a generated schema type is currently unspecified, because Java reflection does not impose a return order. Lack of reliable element ordering impacts application portability. Two annotations for defining schema element ordering are provided for applications that wish to remain portable across JAXB Providers, @XmlAccessorOrder and @XmlType.propOrder. -- @XmlAccessorOrder @XmlAccessorOrder annotation imposes one of two element ordering algorithms, XmlAccessOrder.UNDEFINED or XmlAccessOrder.ALPHABETICAL. XmlAccessOrder.UNDEFINED is the default setting. The order is dependent on the system's reflection implementation. XmlAccessOrder.ALPHABETICAL orders the elements in lexicographic order as determined by java.lang.String.CompareTo(String anotherString). @XmlAccessorOrder can be defined for annotation type ElementType.PACKAGE or on a class object. When @XmlAccessorOrder is defined on a package, the scope of the formatting rule is active for every class in the package. When defined on a class the rule is active on the contents of that class. There can be multiple @XmlAccessorOrder annotations within a package. The order of precedence is the inner most (class) annotation takes precedence over the outter annotation. For example if @XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL) is defined on a package and @XmlAccessorOrder(XmlAccessOrder.UNDEFINED) is defined on a class in that package the contents of the generated schema type for the class would be in an unspecified order and the contents of the generated schema type for evey other class in the package would be alphabetical order. -- @XmlType.propOrder @XmlType can be defined for a class. The annotation element propOrder() in @XmlType allows the specification of the content order in the generated schema type. When @XmlType.propOrder is used on a class to specify content order, all public properties and public fields in the class must be specified in the parameter list. Any public property or field not desired in the parameter list must be annotated with @XmlAttribute or @XmlTransient. The default content order for @XmlType.propOrder is {} or {""}; not active. In such cases the active @XmlAccessorOrder annotation takes precedence. When class content order is specified by @XmlType.propOrder, it takes precedence over any active @XmlAccessorOrder annotation on the class or package. If @XmlAccessorOrder and @XmlType.propOrder(A, B, ...) annotations are specified on a class, the propOrder always takes precedence no matter the order of the annontation statements. For example in CODE A below the @XmlAccessorOrder annotation preceeds @XmlType.propOrder and in CODE B @XmlType.propOrder preceeds @XmlAccessorOrder. In both scenarios propOrder takes precedence and the identical schema content is generated. CODE A: @XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL) @XmlType(propOrder={"name", "city"}) public class USAddress { : public String getCity() {return city;} public void setCity(String city) {this.city = city;} public String getName() {return name;} public void setName(String name) {this.name = name;} : } CODE B: @XmlType(propOrder={"name", "city"}) @XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL) public class USAddress { : public String getCity() {return city;} public void setCity(String city) {this.city = city;} public String getName() {return name;} public void setName(String name) {this.name = name;} : } SCHEMA GENERATE <xs:complexType name="usAddress"> <xs:sequence> <xs:element name="name" type="xs:string" minOccurs="0"/> <xs:element name="city" type="xs:string" minOccurs="0"/> </xs:sequence> </xs:complexType> -- Code example The purchase order code example demonstrates the affects of schema content ordering using @XmlAccessorOrder annotation at the package and class level, and @XmlType.propOrder on a class. Class package-info.java defines @XmlAccessorOrder to be ALPHABETICAL for the package. The public fields shipTo and billTo in class PurchaseOrderType will be affected in the generated schema content order by this rule. Class USAddress defines @XmlType.propOrder on the class. This demonstates user defined property order superseding ALPHABETICAL order in the generated schema. The generated schema file can be found in directory schemas.