@FunctionalInterface public interface MissingMemberHandlerFactory
BeansLinker
. BeansLinker links these method handles into guarded
invocations for link requests specifying GET_*
and SET_*
StandardOperation
s when it is either certain or possible that the
requested member (property, method, or element) is missing. They will be
linked both for named
and unnamed operations. The
implementer must ensure that the parameter types of the returned method
handle match the parameter types of the call site described in the link
request. The return types can differ, though, to allow
DynamicLinkerFactory.setPrelinkTransformer(jdk.dynalink.linker.GuardedInvocationTransformer)
late return type transformations}. It is allowed to return null
for a
method handle if the default behavior is sufficient.
BeansLinker
is configured without a missing member handler
factory, or the factory returns null
for a particular handler
creation invocation, the default behavior is used. The default behavior is to
return null
from
BeansLinker.getGuardedInvocation(LinkRequest, LinkerServices)
when it
can be determined at link time that the linked operation will never address
an existing member. This lets the DynamicLinker
attempt the next
linker if there is one, or ultimately fail the link request with
NoSuchDynamicMethodException
. For other cases (typically all unnamed
member operations as well as most named operations on collection elements)
BeansLinker
will produce a conditional linkage that will return
null
when invoked at runtime with a name that does not match any
member for getters and silently ignore the passed values for setters.
BeansLinker(MissingMemberHandlerFactory)
Modifier and Type | Method | Description |
---|---|---|
MethodHandle |
createMissingMemberHandler(LinkRequest linkRequest,
LinkerServices linkerServices) |
Returns a method handle suitable for implementing missing member behavior
for a particular link request.
|
MethodHandle createMissingMemberHandler(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception
linkRequest
- the current link requestlinkerServices
- the current link servicesException
- if the operation fails for any reason. Please observe
the class documentation notes for implementing exception-throwing
missing member behavior.
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