Class CompositeTypeBasedGuardingDynamicLinker
java.lang.Object
jdk.dynalink.linker.support.CompositeTypeBasedGuardingDynamicLinker
- All Implemented Interfaces:
GuardingDynamicLinker
,TypeBasedGuardingDynamicLinker
public class CompositeTypeBasedGuardingDynamicLinker
extends Object
implements TypeBasedGuardingDynamicLinker
A composite type-based guarding dynamic linker. When a receiver of a not yet
seen class is encountered, all linkers are queried sequentially on their
TypeBasedGuardingDynamicLinker.canLinkType(Class)
method. The linkers
returning true are then bound to the class, and next time a receiver of same
type is encountered, the linking is delegated to those linkers only, speeding
up dispatch.- Since:
- 9
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Constructor Summary
ConstructorDescriptionCompositeTypeBasedGuardingDynamicLinker
(Iterable<? extends TypeBasedGuardingDynamicLinker> linkers) Creates a new composite type-based linker. -
Method Summary
Modifier and TypeMethodDescriptionboolean
canLinkType
(Class<?> type) Returns true if at least one of the composite linkers returns true fromTypeBasedGuardingDynamicLinker.canLinkType(Class)
for the type.getGuardedInvocation
(LinkRequest linkRequest, LinkerServices linkerServices) Creates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.static List
<GuardingDynamicLinker> optimize
(Iterable<? extends GuardingDynamicLinker> linkers) Optimizes a list of type-based linkers.
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Constructor Details
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CompositeTypeBasedGuardingDynamicLinker
public CompositeTypeBasedGuardingDynamicLinker(Iterable<? extends TypeBasedGuardingDynamicLinker> linkers) Creates a new composite type-based linker.- Parameters:
linkers
- the component linkers- Throws:
NullPointerException
- iflinkers
or any of its elements are null.
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Method Details
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canLinkType
Returns true if at least one of the composite linkers returns true fromTypeBasedGuardingDynamicLinker.canLinkType(Class)
for the type.- Specified by:
canLinkType
in interfaceTypeBasedGuardingDynamicLinker
- Parameters:
type
- the type to link- Returns:
- true true if at least one of the composite linkers returns true
from
TypeBasedGuardingDynamicLinker.canLinkType(Class)
, false otherwise.
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getGuardedInvocation
public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception Description copied from interface:GuardingDynamicLinker
Creates a guarded invocation appropriate for a particular invocation with the specified arguments at a call site.- Specified by:
getGuardedInvocation
in interfaceGuardingDynamicLinker
- Parameters:
linkRequest
- the object describing the request for linking a particular invocationlinkerServices
- 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
Throwable
subclass that describes an expected exception condition that also triggers relinking (often it is faster to rely on an infrequent but expectedClassCastException
than on an always evaluatedinstanceof
guard). 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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optimize
public static List<GuardingDynamicLinker> optimize(Iterable<? extends GuardingDynamicLinker> linkers) Optimizes a list of type-based linkers. If a group of adjacent linkers in the list all implementTypeBasedGuardingDynamicLinker
, they will be replaced with a single instance ofCompositeTypeBasedGuardingDynamicLinker
that contains them.- Parameters:
linkers
- the list of linkers to optimize- Returns:
- the optimized list
- Throws:
NullPointerException
- iflinkers
or any of its elements are null.
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