- All Known Subinterfaces:
- TypeBasedGuardingDynamicLinker
- All Known Implementing Classes:
- BeansLinker,- CompositeGuardingDynamicLinker,- CompositeTypeBasedGuardingDynamicLinker
public interface GuardingDynamicLinker
The base interface for language-specific dynamic linkers. Such linkers
 always have to produce method handles with guards, as the validity of the
 method handle for calls at a call site inevitably depends on some condition
 (at the very least, it depends on the receiver belonging to the language
 runtime of the linker). Language runtime implementors will normally implement
 the linking logic for their own language as one or more
 
GuardingDynamicLinker classes. They will typically set them as
 prioritized linkers
 in the DynamicLinkerFactory they configure for themselves, and maybe also
 set some as fallback
 linkers to handle language-specific "property not found" etc. conditions.
 
 Consider implementing TypeBasedGuardingDynamicLinker interface
 instead of this interface for those linkers that are based on the Java class
 of the objects. If you need to implement language-specific type conversions,
 have your GuardingDynamicLinker also implement the
 GuardingTypeConverterFactory interface.
 
 Languages can export linkers to other language runtimes for
 automatic discovery
 using a GuardingDynamicLinkerExporter.
- 
Method SummaryModifier and TypeMethodDescriptiongetGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) Creates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.
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Method Details- 
getGuardedInvocationGuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception Creates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.- Parameters:
- linkRequest- the object describing the request for linking a particular invocation
- linkerServices- linker services
- Returns:
- a guarded invocation with a method handle suitable for the
 arguments, as well as a guard condition that if fails should trigger
 relinking. Must return null if it can't resolve the invocation. If the
 returned invocation is unconditional (which is actually quite rare), the
 guard in the return value can be null. The invocation can also have any
 number of switch points for asynchronous invalidation of the linkage, as
 well as a Throwablesubclass that describes an expected exception condition that also triggers relinking (often it is faster to rely on an infrequent but expectedClassCastExceptionthan on an always evaluatedinstanceofguard). While the linker must produce an invocation with parameter types matching those in the call site descriptor of the link request, it should not try to match the return type expected at the call site except when it can do it with only the conversions that lose neither precision nor magnitude, seeLinkerServices.asTypeLosslessReturn(MethodHandle, MethodType)for further explanation.
- Throws:
- Exception- if the operation fails for whatever reason
 
 
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