- All Known Implementing Classes:
AbstractRelinkableCallSite
,ChainedCallSite
,SimpleRelinkableCallSite
public interface RelinkableCallSite
Interface for call sites managed by a
DynamicLinker
. Users of
Dynalink must use subclasses of CallSite
that also implement this
interface as their call site implementations. There is a readily usable
SimpleRelinkableCallSite
subclass that implements monomorphic inline
caching strategy as well as ChainedCallSite
that implements a
polymorphic inline caching strategy and retains a chain of previously linked
method handles. A relinkable call site will be managed by a
DynamicLinker
object after being associated with it using its
DynamicLinker.link(RelinkableCallSite)
method.-
Method Summary
Modifier and TypeMethodDescriptionReturns the descriptor for this call site.void
initialize
(MethodHandle relinkAndInvoke) Invoked by dynamic linker to initialize the relinkable call site by setting a relink-and-invoke method handle.void
relink
(GuardedInvocation guardedInvocation, MethodHandle relinkAndInvoke) This method will be called by the dynamic linker every time the call site is relinked (but seeresetAndRelink(GuardedInvocation, MethodHandle)
for an exception).void
resetAndRelink
(GuardedInvocation guardedInvocation, MethodHandle relinkAndInvoke) This method will be called by the dynamic linker every time the call site is relinked and the linker wishes the call site to throw away any prior linkage state (that is how it differs fromrelink(GuardedInvocation, MethodHandle)
).
-
Method Details
-
initialize
Invoked by dynamic linker to initialize the relinkable call site by setting a relink-and-invoke method handle. The call site implementation is supposed to set this method handle as its target usingCallSite.setTarget(MethodHandle)
. Relink-and-invoke is the initial method handle set byDynamicLinker.link(RelinkableCallSite)
that will cause the call site to be relinked to an appropriate target on its first invocation based on its arguments, and that linked target will then be invoked (hence the name). This linking protocol effectively delays linking until the call site is invoked with actual arguments and thus ensures that linkers can make nuanced linking decisions based on those arguments and not just on the static method type of the call site.- Parameters:
relinkAndInvoke
- a relink-and-invoke method handle supplied by Dynalink.
-
getDescriptor
CallSiteDescriptor getDescriptor()Returns the descriptor for this call site.- Returns:
- the descriptor for this call site.
-
relink
This method will be called by the dynamic linker every time the call site is relinked (but seeresetAndRelink(GuardedInvocation, MethodHandle)
for an exception). It will be passed aGuardedInvocation
that the call site should incorporate into its target method handle. When this method is called, the call site is allowed to keep other non-invalidated invocations around for implementation of polymorphic inline caches and compose them with this invocation to form its final target.- Parameters:
guardedInvocation
- the guarded invocation that the call site should incorporate into its target method handle.relinkAndInvoke
- a relink-and-invoke method handle. This is a method handle matching the method type of the call site that is supplied by theDynamicLinker
as a callback. It should be used by this call site as the ultimate fallback when it can't invoke its target with the passed arguments. The fallback method is such that when it's invoked, it'll try to obtain an adequate targetGuardedInvocation
for the invocation, and subsequently invokerelink(GuardedInvocation, MethodHandle)
orresetAndRelink(GuardedInvocation, MethodHandle)
, and finally invoke the target.
-
resetAndRelink
This method will be called by the dynamic linker every time the call site is relinked and the linker wishes the call site to throw away any prior linkage state (that is how it differs fromrelink(GuardedInvocation, MethodHandle)
). It will be passed aGuardedInvocation
that the call site should use to build its new target method handle. When this method is called, the call site is discouraged from keeping any previous state, and is supposed to only link the current invocation.- Parameters:
guardedInvocation
- the guarded invocation that the call site should use to build its target method handle.relinkAndInvoke
- a relink-and-invoke method handle. This is a method handle matching the method type of the call site that is supplied by theDynamicLinker
as a callback. It should be used by this call site as the ultimate fallback when it can't invoke its target with the passed arguments. The fallback method is such that when it's invoked, it'll try to obtain an adequate targetGuardedInvocation
for the invocation, and subsequently invokerelink(GuardedInvocation, MethodHandle)
orresetAndRelink(GuardedInvocation, MethodHandle)
, and finally invoke the target.
-