Marshallerpublic 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 all following code fragments:
JAXBContext jc = JAXBContext.newInstance( "com.acme.foo" );
Unmarshaller u = jc.createUnmarshaller();
Object element = u.unmarshal( new File( "foo.xml" ) );
Marshaller m = jc.createMarshaller();
Marshalling to a File:
OutputStream os = new FileOutputStream( "nosferatu.xml" );
m.marshal( element, os );
Marshalling to a SAX ContentHandler:
// assume MyContentHandler instanceof ContentHandler
m.marshal( element, 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, doc );
Marshalling to a java.io.OutputStream:
m.marshal( element, System.out );
Marshalling to a java.io.Writer:
m.marshal( element, new PrintWriter( System.out ) );
Marshalling to a javax.xml.transform.SAXResult:
// assume MyContentHandler instanceof ContentHandler
SAXResult result = new SAXResult( new MyContentHandler() );
m.marshal( element, result );
Marshalling to a javax.xml.transform.DOMResult:
DOMResult result = new DOMResult();
m.marshal( element, result );
Marshalling to a javax.xml.transform.StreamResult:
StreamResult result = new StreamResult( System.out );
m.marshal( element, result );
Marshalling to a javax.xml.stream.XMLStreamWriter:
XMLStreamWriter xmlStreamWriter =
XMLOutputFactory.newInstance().createXMLStreamWriter( ... );
m.marshal( element, xmlStreamWriter );
Marshalling to a javax.xml.stream.XMLEventWriter:
XMLEventWriter xmlEventWriter =
XMLOutputFactory.newInstance().createXMLEventWriter( ... );
m.marshal( element, xmlEventWriter );
Marshalling content tree rooted by a JAXB element
The first parameter of the overloaded
Marshaller.marshal(java.lang.Object, ...) methods must be a
JAXB element as computed by
{@link JAXBIntrospector#isElement(java.lang.Object)};
otherwise, a Marshaller.marshal method must throw a
{@link 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 {@link JAXBElement},
and pass the wrapper element as the first parameter to
a Marshaller.marshal method. For java to schema binding, it
is also possible to simply annotate the instance's class with
@{@link XmlRootElement}.
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
{@link #setProperty(String,Object) 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 default 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, {@link javax.xml.bind.helpers.DefaultValidationEventHandler} is
no longer used.
Supported Properties
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:
- {@link #marshal(Object,org.xml.sax.ContentHandler) marshal(Object,ContentHandler)} - the Marshaller won't
invoke {@link org.xml.sax.ContentHandler#startDocument()} and
{@link org.xml.sax.ContentHandler#endDocument()}.
- {@link #marshal(Object,org.w3c.dom.Node) marshal(Object,Node)} - the property has no effect on this
API.
- {@link #marshal(Object,java.io.OutputStream) marshal(Object,OutputStream)} - the Marshaller won't
generate an xml declaration.
- {@link #marshal(Object,java.io.Writer) marshal(Object,Writer)} - the Marshaller won't
generate an xml declaration.
- {@link #marshal(Object,javax.xml.transform.Result) marshal(Object,Result)} - depends on the kind of
Result object, see semantics for Node, ContentHandler, and Stream APIs
- {@link #marshal(Object,javax.xml.stream.XMLEventWriter) marshal(Object,XMLEventWriter)} - the
Marshaller will not generate {@link javax.xml.stream.events.XMLEvent#START_DOCUMENT} and
{@link javax.xml.stream.events.XMLEvent#END_DOCUMENT} events.
- {@link #marshal(Object,javax.xml.stream.XMLStreamWriter) marshal(Object,XMLStreamWriter)} - the
Marshaller will not generate {@link javax.xml.stream.events.XMLEvent#START_DOCUMENT} and
{@link javax.xml.stream.events.XMLEvent#END_DOCUMENT} events.
Marshal Event Callbacks
"The {@link 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:
// Invoked by Marshaller after it has created an instance of this object.
boolean beforeMarshal(Marshaller);
// Invoked by Marshaller after it has marshalled all properties of this object.
void afterMmarshal(Marshaller);
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.
The external listener callback mechanism enables the registration of a {@link Listener}
instance with a {@link Marshaller#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 {@link Listener#beforeMarshal(Object)} and {@link Listener#afterMarshal(Object)}.
An event callback method throwing an exception terminates the current marshal process.
|
| Fields Summary |
|---|
| public static final String | JAXB_ENCODINGThe name of the property used to specify the output encoding in
the marshalled XML data. | | public static final String | JAXB_FORMATTED_OUTPUTThe name of the property used to specify whether or not the marshalled
XML data is formatted with linefeeds and indentation. | | public static final String | JAXB_SCHEMA_LOCATIONThe name of the property used to specify the xsi:schemaLocation
attribute value to place in the marshalled XML output. | | public static final String | JAXB_NO_NAMESPACE_SCHEMA_LOCATIONThe name of the property used to specify the
xsi:noNamespaceSchemaLocation attribute value to place in the marshalled
XML output. | | public static final String | JAXB_FRAGMENTThe name of the property used to specify whether or not the marshaller
will generate document level events (ie calling startDocument or endDocument). |
| Methods Summary |
|---|
| public A | getAdapter(java.lang.Class type)Gets the adapter associated with the specified type.
This is the reverse operation of the {@link #setAdapter} method.
| | public javax.xml.bind.attachment.AttachmentMarshaller | getAttachmentMarshaller()
| | public javax.xml.bind.ValidationEventHandler | getEventHandler()Return the current event handler or the default event handler if one
hasn't been set.
| | public javax.xml.bind.Marshaller$Listener | getListener()Return {@link Listener} registered with this {@link Marshaller}.
| | public org.w3c.dom.Node | getNode(java.lang.Object contentTree)Get a DOM tree view of the content tree(Optional).
If the returned DOM tree is updated, these changes are also
visible in the content tree.
Use {@link #marshal(Object, org.w3c.dom.Node)} to force
a deep copy of the content tree to a DOM representation.
| | public java.lang.Object | getProperty(java.lang.String name)Get the particular property in the underlying implementation of
Marshaller. This method can only be used to get one of
the standard JAXB defined properties above or a provider specific
property. Attempting to get an undefined property will result in
a PropertyException being thrown. See
Supported Properties.
| | public javax.xml.validation.Schema | getSchema()Get the JAXP 1.3 {@link javax.xml.validation.Schema Schema} object
being used to perform marshal-time validation. If there is no
Schema set on the marshaller, then this method will return null
indicating that marshal-time validation will not be performed.
| | public void | marshal(java.lang.Object jaxbElement, javax.xml.transform.Result result)Marshal the content tree rooted at jaxbElement into the specified
javax.xml.transform.Result.
All JAXB Providers must at least support
{@link javax.xml.transform.dom.DOMResult},
{@link javax.xml.transform.sax.SAXResult}, and
{@link javax.xml.transform.stream.StreamResult}. It can
support other derived classes of Result as well.
| | public void | marshal(java.lang.Object jaxbElement, java.io.OutputStream os)Marshal the content tree rooted at jaxbElement into an output stream.
| | public void | marshal(java.lang.Object jaxbElement, java.io.File output)Marshal the content tree rooted at jaxbElement into a file.
| | public void | marshal(java.lang.Object jaxbElement, java.io.Writer writer)Marshal the content tree rooted at jaxbElement into a Writer.
| | public void | marshal(java.lang.Object jaxbElement, org.xml.sax.ContentHandler handler)Marshal the content tree rooted at jaxbElement into SAX2 events.
| | public void | marshal(java.lang.Object jaxbElement, org.w3c.dom.Node node)Marshal the content tree rooted at jaxbElement into a DOM tree.
| | public void | marshal(java.lang.Object jaxbElement, javax.xml.stream.XMLStreamWriter writer)Marshal the content tree rooted at jaxbElement into a
{@link javax.xml.stream.XMLStreamWriter}.
| | public void | marshal(java.lang.Object jaxbElement, javax.xml.stream.XMLEventWriter writer)Marshal the content tree rooted at jaxbElement into a
{@link javax.xml.stream.XMLEventWriter}.
| | public void | setAdapter(javax.xml.bind.annotation.adapters.XmlAdapter adapter)Associates a configured instance of {@link XmlAdapter} with this marshaller.
This is a convenience method that invokes setAdapter(adapter.getClass(),adapter);.
| | public void | setAdapter(java.lang.Class type, A adapter)Associates a configured instance of {@link XmlAdapter} with this marshaller.
Every marshaller internally maintains a
{@link java.util.Map}<{@link Class},{@link XmlAdapter}>,
which it uses for marshalling classes whose fields/methods are annotated
with {@link javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter}.
This method allows applications to use a configured instance of {@link XmlAdapter}.
When an instance of an adapter is not given, a marshaller will create
one by invoking its default constructor.
| | public void | setAttachmentMarshaller(javax.xml.bind.attachment.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.
| | public void | setEventHandler(javax.xml.bind.ValidationEventHandler handler)Allow an application to register a validation event handler.
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.
| | public void | setListener(javax.xml.bind.Marshaller$Listener listener)
Register marshal event callback {@link Listener} with this {@link 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.
| | public void | setProperty(java.lang.String name, java.lang.Object value)Set the particular property in the underlying implementation of
Marshaller. This method can only be used to set one of
the standard JAXB defined properties above or a provider specific
property. Attempting to set an undefined property will result in
a PropertyException being thrown. See
Supported Properties.
| | public void | setSchema(javax.xml.validation.Schema schema)Specify the JAXP 1.3 {@link javax.xml.validation.Schema Schema}
object that should be used to validate subsequent marshal operations
against. Passing null into this method will disable validation.
This method allows the caller to validate the marshalled XML as it's marshalled.
Initially this property is set to null.
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