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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 in all following code fragments:
JAXBContext jc = JAXBContext.newInstance( "com.acme.foo" ); Unmarshaller u = jc.createUnmarshaller(); FooObject obj = (FooObject)u.unmarshal( new File( "foo.xml" ) ); Marshaller m = jc.createMarshaller();
Marshalling to a File:
OutputStream os = new FileOutputStream( "nosferatu.xml" ); m.marshal( obj, os );
Marshalling to a SAX ContentHandler:
// assume MyContentHandler instanceof ContentHandler m.marshal( 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( obj, doc );
Marshalling to a java.io.OutputStream:
m.marshal( obj, System.out );
Marshalling to a java.io.Writer:
m.marshal( obj, new PrintWriter( System.out ) );
Marshalling to a javax.xml.transform.SAXResult:
// assume MyContentHandler instanceof ContentHandler SAXResult result = new SAXResult( new MyContentHandler() ); m.marshal( obj, result );
Marshalling to a javax.xml.transform.DOMResult:
DOMResult result = new DOMResult(); m.marshal( obj, result );
Marshalling to a javax.xml.transform.StreamResult:
StreamResult result = new StreamResult( System.out ); m.marshal( obj, result );
Marshalling java.lang.Object Objects
Although each of the marshal methods accepts a java.lang.Object as
its first parameter, JAXB Providers are not required to be able to marshal
any arbitrary java.lang.Object. If the JAXBContext
object that was used to create this Marshaller does not have enough
information to know how to marshal the object parameter (or any objects
reachable from it), then the marshal operation will throw a
MarshalException
. Even though JAXB Providers are not
required to be able to marshal arbitrary java.lang.Object objects,
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 ouput
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.
Although there is no way to enable validation during the marshal operation, it is possible that certain types of validation events will be detected during the operation. These 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 the default event handler which will terminate the marshal operation after encountering the first error or fatal error.
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.
JAXBContext
,
Validator
,
Unmarshaller
Field Summary | |
static java.lang.String |
JAXB_ENCODING
The name of the property used to specify the output encoding in the marshalled XML data. |
static java.lang.String |
JAXB_FORMATTED_OUTPUT
The name of the property used to specify whether or not the marshalled XML data is formated with linefeeds and indentation. |
static java.lang.String |
JAXB_NO_NAMESPACE_SCHEMA_LOCATION
The name of the property used to specify the the xsi:noNamespaceSchemaLocation attribute value to place in the marshalled XML output. |
static java.lang.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 | |
ValidationEventHandler |
getEventHandler()
Return the current event handler or the default event handler if one hasn't been set. |
Node |
getNode(java.lang.Object contentTree)
Get a DOM tree view of the content tree(Optional). |
java.lang.Object |
getProperty(java.lang.String name)
Get the particular property in the underlying implementation of Marshaller. |
void |
marshal(java.lang.Object obj,
ContentHandler handler)
Marshal the content tree rooted at obj into SAX2 events. |
void |
marshal(java.lang.Object obj,
Node node)
Marshal the content tree rooted at obj into a DOM tree. |
void |
marshal(java.lang.Object obj,
java.io.OutputStream os)
Marshal the content tree rooted at obj into an output stream. |
void |
marshal(java.lang.Object obj,
Result result)
Marshal the content tree rooted at obj into the specified javax.xml.transform.Result. |
void |
marshal(java.lang.Object obj,
java.io.Writer writer)
Marshal the content tree rooted at obj into a Writer. |
void |
setEventHandler(ValidationEventHandler handler)
Allow an application to register a validation event handler. |
void |
setProperty(java.lang.String name,
java.lang.Object value)
Set the particular property in the underlying implementation of Marshaller. |
Field Detail |
public static final java.lang.String JAXB_ENCODING
public static final java.lang.String JAXB_FORMATTED_OUTPUT
public static final java.lang.String JAXB_SCHEMA_LOCATION
public static final java.lang.String JAXB_NO_NAMESPACE_SCHEMA_LOCATION
Method Detail |
public void marshal(java.lang.Object 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.
obj
- The content tree to be marshalled.result
- XML will be sent to this Result
JAXBException
- If any unexpected problem occurs during the marshalling.
MarshalException
- If the ValidationEventHandler
returns false from its handleEvent method or the
Marshaller is unable to marshal obj (or any
object reachable from obj). See
Marshalling objects.
java.lang.IllegalArgumentException
- If any of the method parameters are nullpublic void marshal(java.lang.Object obj, java.io.OutputStream os) throws JAXBException
obj
- The content tree to be marshalled.os
- XML will be added to this stream.
JAXBException
- If any unexpected problem occurs during the marshalling.
MarshalException
- If the ValidationEventHandler
returns false from its handleEvent method or the
Marshaller is unable to marshal obj (or any
object reachable from obj). See
Marshalling objects.
java.lang.IllegalArgumentException
- If any of the method parameters are nullpublic void marshal(java.lang.Object obj, java.io.Writer writer) throws JAXBException
obj
- The content tree to be marshalled.writer
- XML will be sent to this writer.
JAXBException
- If any unexpected problem occurs during the marshalling.
MarshalException
- If the ValidationEventHandler
returns false from its handleEvent method or the
Marshaller is unable to marshal obj (or any
object reachable from obj). See
Marshalling objects.
java.lang.IllegalArgumentException
- If any of the method parameters are nullpublic void marshal(java.lang.Object obj, ContentHandler handler) throws JAXBException
obj
- The content tree to be marshalled.handler
- XML will be sent to this handler as SAX2 events.
JAXBException
- If any unexpected problem occurs during the marshalling.
MarshalException
- If the ValidationEventHandler
returns false from its handleEvent method or the
Marshaller is unable to marshal obj (or any
object reachable from obj). See
Marshalling objects.
java.lang.IllegalArgumentException
- If any of the method parameters are nullpublic void marshal(java.lang.Object obj, Node node) throws JAXBException
obj
- The content tree to be marshalled.node
- DOM nodes will be added as children of this node.
This parameter must be a Node that accepts children
(Document
,
DocumentFragment
, or
Element
)
JAXBException
- If any unexpected problem occurs during the marshalling.
MarshalException
- If the ValidationEventHandler
returns false from its handleEvent method or the
Marshaller is unable to marshal obj (or any
object reachable from obj). See
Marshalling objects.
java.lang.IllegalArgumentException
- If any of the method parameters are nullpublic Node getNode(java.lang.Object contentTree) throws JAXBException
marshal(Object, org.w3c.dom.Node)
to force
a deep copy of the content tree to a DOM representation.
contentTree
- - JAXB Java representation of XML content
java.lang.UnsupportedOperationException
- If the JAXB provider implementation does not support a
DOM view of the content tree
java.lang.IllegalArgumentException
- If any of the method parameters are null
JAXBException
- If any unexpected problem occurspublic void setProperty(java.lang.String name, java.lang.Object value) throws PropertyException
name
- the name of the property to be set. This value can either
be specified using one of the constant fields or a user
supplied string.value
- the value of the property to be set
PropertyException
- when there is an error processing the given
property or value
java.lang.IllegalArgumentException
- If the name parameter is nullpublic java.lang.Object getProperty(java.lang.String name) throws PropertyException
name
- the name of the property to retrieve
PropertyException
- when there is an error retrieving the given property or value
property name
java.lang.IllegalArgumentException
- If the name parameter is nullpublic 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 vefault event handler.
handler
- the validation event handler
JAXBException
- if an error was encountered while setting the
event handlerpublic ValidationEventHandler getEventHandler() throws JAXBException
JAXBException
- if an error was encountered while getting the
current event handler
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