public abstract class IDResolver extends Object
THIS INTERFACE IS SUBJECT TO CHANGE WITHOUT NOTICE.
This 'interface' can be implemented by applications and specified to
Unmarshaller.setProperty(String, Object) to ovierride the ID/IDREF
processing of the JAXB RI like this:
This component runs inside the JAXB RI unmarshaller. Therefore, it needs to coordinate with the JAXB RI unmarshaller when it comes to reporting errors. This makes sure that applications see consistent error handling behaviors.
startDocument(ValidationEventHandler) method is invoked,
the unmarshaller passes in a
ValidationEventHandler that can be used
by this component to report any errors encountered during the ID/IDREF processing.
When an error is detected, the error should be first reported to this
ValidationEventHandler. If the error is fatal or the event handler
decided to abort, the implementation should throw a
This signals the unmarshaller to abort the processing.
|Constructor and Description|
|Modifier and Type||Method and Description|
Binds the given object to the specified ID.
Called after the unmarshalling completes.
Obtains the object to be pointed by the IDREF value.
Called when the unmarshalling starts.
public void startDocument(ValidationEventHandler eventHandler) throws SAXException
Unmarshaller may be used multiple times
to unmarshal documents, one
IDResolver may be used multiple times, too.
eventHandler- Any errors found during the unmarshalling should be reported to this object.
public void endDocument() throws SAXException
This is a good opporunity to reset any internal state of this object, so that it doesn't keep references to other objects unnecessarily.
public abstract void bind(String id, Object obj) throws SAXException
While a document is being unmarshalled, every time an ID value is found, this method is invoked to remember the association between ID and objects. This association is supposed to be used later to resolve IDREFs.
This method is invoked right away as soon as a new ID value is found.
id- The ID value found in the document being unmarshalled. Always non-null.
obj- The object being unmarshalled which is going to own the ID. Always non-null.
public abstract Callable<?> resolve(String id, Class targetType) throws SAXException
While a document is being unmarshalled, every time an IDREF value is found, this method is invoked immediately to obtain the object that the IDREF is pointing to.
This method returns a
Callable to support forward-references.
When this method returns with a non-null return value,
the JAXB RI unmarshaller invokes the
Callable.call() method immediately.
If the implementation can find the target object (in which case
it was a backward reference), then a non-null object shall be returned,
and it is used as the target object.
When a forward-reference happens, the
should return null. In this case the JAXB RI unmarshaller invokes
call method again after all the documents are fully unmarshalled.
call method still returns null, then the JAXB RI unmarshaller
treats it as an error.
Callable object returned from this method may not throw
any exception other than a
SAXException (which means a fatal error.)
id- The IDREF value found in the document being unmarshalled. Always non-null.
targetType- The expected type to which ID resolves to. JAXB infers this information from the signature of the fields that has
XmlIDREF. When a property is a collection, this parameter will be the type of the individual item in the collection.
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