public interface Marshaller
The Marshaller class is responsible for governing the process of serializing Java content trees back into XML data. It provides the basic marshalling methods:
Assume the following setup code
for
in
all following code fragments:
JAXBContext jc = JAXBContext.newInstance( "com.acme.foo" ); Unmarshaller u = jc.createUnmarshaller(); Object elementFooObject obj= u.unmarshal((FooObject)u.unmarshal(new File( "foo.xml" ) ); Marshaller m = jc.createMarshaller();
Marshalling to a File:
OutputStream os = new FileOutputStream( "nosferatu.xml" ); m.marshal( element,obj,os );
Marshalling to a SAX ContentHandler:
// assume MyContentHandler instanceof ContentHandler m.marshal( element,obj,new MyContentHandler() );
Marshalling to a DOM Node:
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); dbf.setNamespaceAware(true); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.newDocument(); m.marshal( element,obj,doc );
Marshalling to a java.io.OutputStream:
m.marshal( element,obj,System.out );
Marshalling to a java.io.Writer:
m.marshal( element,obj,new PrintWriter( System.out ) );
Marshalling to a javax.xml.transform.SAXResult:
// assume MyContentHandler instanceof ContentHandler SAXResult result = new SAXResult( new MyContentHandler() ); m.marshal( element,obj,result );
Marshalling to a javax.xml.transform.DOMResult:
DOMResult result = new DOMResult(); m.marshal( element,obj,result );
Marshalling to a javax.xml.transform.StreamResult:
StreamResult result = new StreamResult( System.out ); m.marshal( element,obj,result );
Marshalling to a javax.xml.stream.XMLStreamWriter:
XMLStreamWriter xmlStreamWriter = XMLOutputFactory.newInstance().createXMLStreamWriter( ... ); m.marshal( element,obj,xmlStreamWriter );
Marshalling to a javax.xml.stream.XMLEventWriter:
XMLEventWriter xmlEventWriter = XMLOutputFactory.newInstance().createXMLEventWriter( ... ); m.marshal( element,obj,xmlEventWriter );
Marshalling content tree rooted by a JAXB element
Marshalling
java.lang.Object
Objects
The first parameter of the overloadedAlthough each of the marshal methods accepts aMarshaller.marshal(java.lang.Object, ...)java.lang.Objectmethods must be a JAXB element as computed by JAXBIntrospector.isElement(java.lang.Object) ; otherwise, aas its first parameter, JAXB Providers are not required to be able to marshalanyarbitraryMarshaller.marshaljava.lang.Objectmethod must throw a MarshalException . There exist two mechanisms to enable marshalling an instance that is not a JAXB element. One method is to wrap the instance as a value of a JAXBElement , and pass the wrapper element as the first parameter to aIf theMarshaller.marshalJAXBContextmethod. For java to schema binding, it is also possible to simply annotate the instance's class with @ XmlRootElementobject that was used to create thisMarshallerdoes not have enough information to know how to marshal the object parameter (or any objects reachable from it), then the marshal operation will throw aMarshalException.Even though JAXB Providers are not required to be able to marshal arbitraryjava.lang.Objectobjects, some providers may allow it.
Encoding
By default, the Marshaller will use UTF-8 encoding when generating XML data to a java.io.OutputStream , or a java.io.Writer . Use the setProperty API to change the output encoding used during these marshal operations. Client applications are expected to supply a valid character encoding name as defined in the W3C XML 1.0 Recommendation and supported by your Java Platform .
Validation and Well-Formedness
Client applications are not required to validate the Java content tree prior to calling any of the marshal API's. Furthermore, there is no requirement that the Java content tree be valid with respect to its original schema in order to marshal it back into XML data. Different JAXB Providers will support marshalling invalid Java content trees at varying levels, however all JAXB Providers must be able to marshal a valid content tree back to XML data. A JAXB Provider must throw a MarshalException when it is unable to complete the marshal operation due to invalid content. Some JAXB Providers will fully allow marshalling invalid content, others will fail on the first validation error.
Even when schema validation is not explictly enabled for the marshal operation, it is possible that certain types of validation events will be detected during the operation. Validation events will be reported to the registered event handler. If the client application has not registered an event handler prior to invoking one of the marshal API's, then events will be delivered to a
thedefault event handler which will terminate the marshal operation after encountering the first error or fatal error. Note that for JAXB 2.0 and later versions, DefaultValidationEventHandler is no longer used.
All JAXB Providers are required to support the following set of properties. Some providers may support additional properties.
- jaxb.encoding - value must be a java.lang.String
- The output encoding to use when marshalling the XML data. The Marshaller will use "UTF-8" by default if this property is not specified.
- jaxb.formatted.output - value must be a java.lang.Boolean
- This property controls whether or not the Marshaller will format the resulting XML data with line breaks and indentation. A true value for this property indicates human readable indented xml data, while a false value indicates unformatted xml data. The Marshaller will default to false (unformatted) if this property is not specified.
- jaxb.schemaLocation - value must be a java.lang.String
- This property allows the client application to specify an xsi:schemaLocation attribute in the generated XML data. The format of the schemaLocation attribute value is discussed in an easy to understand, non-normative form in Section 5.6 of the W3C XML Schema Part 0: Primer and specified in Section 2.6 of the W3C XML Schema Part 1: Structures .
- jaxb.noNamespaceSchemaLocation - value must be a java.lang.String
- This property allows the client application to specify an xsi:noNamespaceSchemaLocation attribute in the generated XML data. The format of the schemaLocation attribute value is discussed in an easy to understand, non-normative form in Section 5.6 of the W3C XML Schema Part 0: Primer and specified in Section 2.6 of the W3C XML Schema Part 1: Structures .
- jaxb.fragment - value must be a java.lang.Boolean
- This property determines whether or not document level events will be generated by the Marshaller. If the property is not specified, the default is false . This property has different implications depending on which marshal api you are using - when this property is set to true:
- marshal(Object,ContentHandler) - the Marshaller won't invoke ContentHandler.startDocument() and ContentHandler.endDocument() .
- marshal(Object,Node) - the property has no effect on this API.
- marshal(Object,OutputStream) - the Marshaller won't generate an xml declaration.
- marshal(Object,Writer) - the Marshaller won't generate an xml declaration.
- marshal(Object,Result) - depends on the kind of Result object, see semantics for Node, ContentHandler, and Stream APIs
- marshal(Object,XMLEventWriter) - the Marshaller will not generate XMLStreamConstants.START_DOCUMENT and XMLStreamConstants.END_DOCUMENT events.
- marshal(Object,XMLStreamWriter) - the Marshaller will not generate XMLStreamConstants.START_DOCUMENT and XMLStreamConstants.END_DOCUMENT events.
"The Marshaller provides two styles of callback mechanisms that allow application specific processing during key points in the unmarshalling process. In 'class defined' event callbacks, application specific code placed in JAXB mapped classes is triggered during marshalling. 'External listeners' allow for centralized processing of marshal events in one callback method rather than by type event callbacks.Class defined event callback methods allow any JAXB mapped class to specify its own specific callback methods by defining methods with the following method signatures:
The class defined event callback methods should be used when the callback method requires access to non-public methods and/or fields of the class.// Invoked by Marshaller after it has created an instance of this object. boolean beforeMarshal(Marshaller, Object parent); // Invoked by Marshaller after it has marshalled all properties of this object. void afterMmarshal(Marshaller, Object parent);The external listener callback mechanism enables the registration of a Marshaller.Listener instance with a setListener(Listener) . The external listener receives all callback events, allowing for more centralized processing than per class defined callback methods.
The 'class defined' and external listener event callback methods are independent of each other, both can be called for one event. The invocation ordering when both listener callback methods exist is defined in Marshaller.Listener.beforeMarshal(Object) and Marshaller.Listener.afterMarshal(Object) .
An event callback method throwing an exception terminates the current marshal process.
Nested Class Summary | |
---|---|
static class |
Marshaller.Listener
Register an instance of an implementation of this class with a Marshaller to externally listen for marshal events. |
Field Summary | |
---|---|
static String |
JAXB_ENCODING
The name of the property used to specify the output encoding in the marshalled XML data. |
static String |
JAXB_FORMATTED_OUTPUT
The name of the property used to specify whether or not the marshalled XML data is formatted with linefeeds and indentation. |
static String |
JAXB_FRAGMENT
The name of the property used to specify whether or not the marshaller will generate document level events (ie calling startDocument or endDocument). |
static String |
JAXB_NO_NAMESPACE_SCHEMA_LOCATION
The name of the property used to specify the xsi:noNamespaceSchemaLocation attribute value to place in the marshalled XML output. |
static String |
JAXB_SCHEMA_LOCATION
The name of the property used to specify the xsi:schemaLocation attribute value to place in the marshalled XML output. |
Method Summary | ||
---|---|---|
|
getAdapter
(
Class
<A> type) Gets the adapter associated with the specified type. |
|
AttachmentMarshaller |
getAttachmentMarshaller
() |
|
ValidationEventHandler |
getEventHandler
() Return the current event handler or the default event handler if one hasn't been set. |
|
Marshaller.Listener |
getListener
() Return Marshaller.Listener registered with this Marshaller . |
|
Node |
getNode
(
Object
contentTree) Get a DOM tree view of the content tree(Optional). |
|
Object |
getProperty
(
String
name) Get the particular property in the underlying implementation of Marshaller . |
|
Schema |
getSchema
() Get the JAXP 1.3 Schema object being used to perform marshal-time validation. |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
void |
marshal
(
Object
jaxbElement,
Marshal the content tree rooted at jaxbElement |
|
|
setAdapter
(
Class
<A> type, A adapter) Associates a configured instance of XmlAdapter with this marshaller. |
|
void |
setAdapter
(
XmlAdapter
adapter) Associates a configured instance of XmlAdapter with this marshaller. |
|
void |
setAttachmentMarshaller
(
AttachmentMarshaller
am) Associate a context that enables binary data within an XML document to be transmitted as XML-binary optimized attachment. |
|
void |
setEventHandler
(
ValidationEventHandler
handler) Allow an application to register a validation event handler. |
|
void |
setListener
(
Marshaller.Listener
listener) Register marshal event callback Marshaller.Listener with this Marshaller . |
|
void |
setProperty
(
String
name,
Object
value) Set the particular property in the underlying implementation of Marshaller . |
|
void |
setSchema
(
Schema
schema) Specify the JAXP 1.3 Schema object that should be used to validate subsequent marshal operations against. |
Field Detail |
---|
static final String JAXB_ENCODING
static final String JAXB_FORMATTED_OUTPUT
static final String JAXB_SCHEMA_LOCATION
static final String JAXB_NO_NAMESPACE_SCHEMA_LOCATION
static final String JAXB_FRAGMENT
Method Detail |
---|
void marshal(Object jaxbElement,obj,Result result) throws JAXBException
All JAXB Providers must at least support DOMResult , SAXResult , and StreamResult . It can support other derived classes of Result as well.
void marshal(Object jaxbElement,obj,OutputStream os) throws JAXBException
void marshal(Object jaxbElement,obj,Writer writer) throws JAXBException
void marshal(Object jaxbElement,obj,ContentHandler handler) throws JAXBException
void marshal(Object jaxbElement,obj,Node node) throws JAXBException
void marshal(Object jaxbElement,obj,XMLStreamWriter writer) throws JAXBException
void marshal(Object jaxbElement,obj,XMLEventWriter writer) throws JAXBException
Node getNode(Object contentTree) throws JAXBException
void setProperty(String name, Object value) throws PropertyException
Object getProperty(String name) throws PropertyException
void setEventHandler(ValidationEventHandler handler) throws JAXBException
The validation event handler will be called by the JAXB Provider if any validation errors are encountered during calls to any of the marshal API's. If the client application does not register a validation event handler before invoking one of the marshal methods, then validation events will be handled by the default event handler which will terminate the marshal operation after the first error or fatal error is encountered.
Calling this method with a null parameter will cause the Marshaller to revert back to the default default event handler.
ValidationEventHandler getEventHandler() throws JAXBException
void setAdapter(XmlAdapter adapter)
This is a convenience method that invokes setAdapter(adapter.getClass(),adapter);.
<A extends XmlAdapter> void setAdapter(Class<A> type, A adapter)
Every marshaller internally maintains a Map < Class , XmlAdapter >, which it uses for marshalling classes whose fields/methods are annotated with XmlJavaTypeAdapter .
This method allows applications to use a configured instance of XmlAdapter . When an instance of an adapter is not given, a marshaller will create one by invoking its default constructor.
<A extends XmlAdapter> A getAdapter(Class<A> type)
void setAttachmentMarshaller(AttachmentMarshaller am)
Associate a context that enables binary data within an XML document to be transmitted as XML-binary optimized attachment. The attachment is referenced from the XML document content model by content-id URIs(cid) references stored within the xml document.
AttachmentMarshaller getAttachmentMarshaller()
void setSchema(Schema schema)
This method allows the caller to validate the marshalled XML as it's marshalled.
Initially this property is set to null .
Schema getSchema()
void setListener(Marshaller.Listener listener)
Register marshal event callback Marshaller.Listener with this Marshaller .
There is only one Listener per Marshaller. Setting a Listener replaces the previous set Listener. One can unregister current Listener by setting listener to null .
Marshaller.Listener getListener()
Return Marshaller.Listener registered with this Marshaller .