org.dynalang.dynalink.support

Class CompositeTypeBasedGuardingDynamicLinker

java.lang.Object

org.dynalang.dynalink.support.CompositeTypeBasedGuardingDynamicLinker

All Implemented Interfaces:

Serializable, GuardingDynamicLinker, TypeBasedGuardingDynamicLinker

public class CompositeTypeBasedGuardingDynamicLinker
extends Object
implements TypeBasedGuardingDynamicLinker, Serializable

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.

Author:

Attila Szegedi

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
CompositeTypeBasedGuardingDynamicLinker(Iterable<? extends TypeBasedGuardingDynamicLinker> linkers) Creates a new composite type-based linker.

Method Summary

Modifier and Type	Method and Description
boolean	canLinkType(Class<?> type) Returns true if the linker can link an invocation where the first argument (receiver) is of the specified type.
GuardedInvocation	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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CompositeTypeBasedGuardingDynamicLinker

public CompositeTypeBasedGuardingDynamicLinker(Iterable<? extends TypeBasedGuardingDynamicLinker> linkers)

Creates a new composite type-based linker.

Parameters:

linkers - the component linkers

Method Detail

canLinkType

public boolean canLinkType(Class<?> type)

Description copied from interface: TypeBasedGuardingDynamicLinker

Returns true if the linker can link an invocation where the first argument (receiver) is of the specified type.

Specified by:

canLinkType in interface TypeBasedGuardingDynamicLinker

Parameters:

type - the type to link

Returns:

true if the linker can link calls for the receiver type, or false otherwise.

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 interface GuardingDynamicLinker

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 a switch point for asynchronous invalidation of the linkage. If the linker does not recognize any native language runtime contexts in arguments, or does recognize its own, but receives a call site descriptor without its recognized context in the arguments, it should invoke LinkRequest.withoutRuntimeContext() and link for that.

Throws:

Exception - if the operation fails for whatever reason

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 implement TypeBasedGuardingDynamicLinker, they will be replaced with a single instance of CompositeTypeBasedGuardingDynamicLinker that contains them.

Parameters:

linkers - the list of linkers to optimize

Returns:

the optimized list