com.sun.xml.bind.api

Class ClassResolver

java.lang.Object

com.sun.xml.bind.api.ClassResolver

public abstract class ClassResolver
extends Object

Dynamically locates classes to represent elements discovered during the unmarshalling.

THIS INTERFACE IS SUBJECT TO CHANGE WITHOUT NOTICE.

Background

JAXBContext.newInstance(Class...) requires that application informs JAXB about all the classes that it may see in the instance document. While this allows JAXB to take time to optimize the unmarshalling, it is sometimes inconvenient for applications.

This is where ClassResolver comes to resucue.

A ClassResolver instance can be specified on Unmarshaller via Unmarshaller.setProperty(String, Object) as follows:

 unmarshaller.setProperty( ClassResolver.class.getName(), new MyClassResolverImpl() );
 

When an Unmarshaller encounters (i) an unknown root element or (ii) unknown elements where unmarshaller is trying to unmarshal into XmlAnyElement with lax=true, unmarshaller calls resolveElementName(String, String) method to see if the application may be able to supply a class that corresponds to that class.

When a Class is returned, a new JAXBContext is created with all the classes known to it so far, plus a new class returned. This operation may fail (for example because of some conflicting annotations.) This failure is handled just like Exceptions thrown from resolveElementName(String, String).

Since:

2.1

Author:

Kohsuke Kawaguchi

Constructor Summary

Constructors

Constructor and Description
ClassResolver()

Method Summary

Modifier and Type	Method and Description
abstract Class<?>	resolveElementName(String nsUri, String localName) JAXB calls this method when it sees an unknown element.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ClassResolver

public ClassResolver()

Method Detail

resolveElementName

@Nullable
public abstract Class<?> resolveElementName(@NotNull
                                                      String nsUri,
                                                      @NotNull
                                                      String localName)
                                               throws Exception

JAXB calls this method when it sees an unknown element.

See the class javadoc for details.

Parameters:

nsUri - Namespace URI of the unknown element. Can be empty but never null.

localName - Local name of the unknown element. Never be empty nor null.

Returns:

If a non-null class is returned, it will be used to unmarshal this element. If null is returned, the resolution is assumed to be failed, and the unmarshaller will behave as if there was no ClassResolver to begin with (that is, to report it to ValidationEventHandler, then move on.)

Throws:

Exception - Throwing any RuntimeException causes the unmarshaller to stop immediately. The exception will be propagated up the call stack. Throwing any other checked Exception results in the error reproted to ValidationEventHandler (just like any other error during the unmarshalling.)