OpenJDK 1.23 · jdk.dynalink.DynamicLinkerFactory · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
private MethodTypeConversionStrategy	autoConversionStrategy
private List<ServiceConfigurationError>	autoLoadingErrors
private ClassLoader	classLoader
private boolean	classLoaderExplicitlySet
private static final int	DEFAULT_UNSTABLE_RELINK_THRESHOLD Default value for `unstable relink threshold`.
private List<? extends GuardingDynamicLinker>	fallbackLinkers
private static final AccessControlContext	GET_CLASS_LOADER_CONTEXT References Deprecated `AccessControlContext` is deprecated or references (maybe indirectly) at least one deprecated element.
private MethodHandleTransformer	internalObjectsFilter
private GuardedInvocationTransformer	prelinkTransformer
private List<? extends GuardingDynamicLinker>	prioritizedLinkers
private boolean	syncOnRelink
private int	unstableRelinkThreshold

Access	Constructor and Description
public	DynamicLinkerFactory() Creates a new dynamic linker factory with default configuration.

Method Summary

Modifier and Type	Method and Description
private static void	addClasses(final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses, final List<? extends GuardingDynamicLinker> linkers)
private static <T> List<T>	copyListRequireNonNullElements(final List<T> list)
public DynamicLinker	Returns: the new dynamic Linker createLinker() Creates a new dynamic linker based on the current configuration.
private List<GuardingDynamicLinker>	discoverAutoLoadLinkers()
public List<ServiceConfigurationError>	Returns: an immutable list of encountered `ServiceConfigurationError`s. Can be empty. getAutoLoadingErrors() Returns a list of `ServiceConfigurationError`s that were encountered while loading automatically discovered linkers during the last invocation of `createLinker()`.
private static ClassLoader	getThreadContextClassLoader()
private static <T> List<T>	requireNonNullElements(final List<T> list, final Supplier<String> msgSupplier)
public void	setAutoConversionStrategy(final MethodTypeConversionStrategy the strategy for applying method invocation conversions for the linker created by this factory. Can be null for no custom strategy. autoConversionStrategy) Sets an object representing the conversion strategy for automatic type conversions.
public void	setClassLoader(final ClassLoader the class loader used for the automatic discovery of available linkers. classLoader) Sets the class loader for automatic discovery of available guarding dynamic linkers.
public void	setFallbackLinkers(final List<? extends GuardingDynamicLinker> the list of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of `BeansLinker` to serve as the default fallback linker. fallbackLinkers) Sets the fallback guarding dynamic linkers.
public void	setFallbackLinkers(final GuardingDynamicLinker... an array of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of `BeansLinker` to serve as the default fallback linker. fallbackLinkers) Sets the fallback guarding dynamic linkers.
public void	setInternalObjectsFilter(final MethodHandleTransformer a method handle transformer filtering out internal objects, or null. internalObjectsFilter) Sets a method handle transformer that is supposed to act as the implementation of `LinkerServices#filterInternalObjects(MethodHandle)` for linker services of dynamic linkers created by this factory.
public void	setPrelinkTransformer(final GuardedInvocationTransformer the pre-link transformer for the dynamic linker. Can be null to have the factory use the default transformer. prelinkTransformer) Set the pre-link transformer.
public void	setPrioritizedLinker(final GuardingDynamicLinker the single prioritized linker. Must not be null. prioritizedLinker) Sets a single prioritized linker.
public void	setPrioritizedLinkers(final List<? extends GuardingDynamicLinker> the list of prioritized linkers. Can be null. prioritizedLinkers) Sets the prioritized guarding dynamic linkers.
public void	setPrioritizedLinkers(final GuardingDynamicLinker... an array of prioritized linkers. Can be null. prioritizedLinkers) Sets the prioritized guarding dynamic linkers.
public void	setSyncOnRelink(final boolean true for invoking sync on relink, false otherwise. syncOnRelink) Sets whether the dynamic linker created by this factory will invoke `MutableCallSite#syncAll(MutableCallSite[])` after a call site is relinked.
public void	setUnstableRelinkThreshold(final int the new threshold. Must not be less than zero. The value of zero means that call sites will never be considered unstable. unstableRelinkThreshold) Sets the unstable relink threshold; the number of times a call site is relinked after which it will be considered unstable, and subsequent link requests for it will indicate this.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

autoConversionStrategy	back to summary
private MethodTypeConversionStrategy autoConversionStrategy

autoLoadingErrors	back to summary
private List<ServiceConfigurationError> autoLoadingErrors

classLoader	back to summary
private ClassLoader classLoader

classLoaderExplicitlySet	back to summary
private boolean classLoaderExplicitlySet

DEFAULT_UNSTABLE_RELINK_THRESHOLD	back to summary
private static final int DEFAULT_UNSTABLE_RELINK_THRESHOLD Default value for `unstable relink threshold`.

fallbackLinkers	back to summary
private List<? extends GuardingDynamicLinker> fallbackLinkers

GET_CLASS_LOADER_CONTEXT	back to summary
private static final AccessControlContext GET_CLASS_LOADER_CONTEXT References Deprecated `AccessControlContext` is deprecated or references (maybe indirectly) at least one deprecated element. See corresponding docs for further information. Annotations @SuppressWarnings:removal

internalObjectsFilter	back to summary
private MethodHandleTransformer internalObjectsFilter

prelinkTransformer	back to summary
private GuardedInvocationTransformer prelinkTransformer

prioritizedLinkers	back to summary
private List<? extends GuardingDynamicLinker> prioritizedLinkers

syncOnRelink	back to summary
private boolean syncOnRelink

unstableRelinkThreshold	back to summary
private int unstableRelinkThreshold

DynamicLinkerFactory	back to summary
public DynamicLinkerFactory() Creates a new dynamic linker factory with default configuration. Upon creation, the factory can be configured using various `setXxx()` methods and used to create one or more dynamic linkers according to its current configuration using `createLinker()`.

Method Detail

addClasses	back to summary
private static void addClasses(final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses, final List<? extends GuardingDynamicLinker> linkers)

copyListRequireNonNullElements	back to summary
private static <T> List<T> copyListRequireNonNullElements(final List<T> list)

createLinker back to summary

createLinker	back to summary
public DynamicLinker createLinker() Creates a new dynamic linker based on the current configuration. This method can be invoked more than once to create multiple dynamic linkers. Automatically discovered linkers are newly instantiated on every invocation of this method. It is allowed to change the factory's configuration between invocations. The method is not thread safe. After invocation, callers can invoke `getAutoLoadingErrors()` to retrieve a list of `ServiceConfigurationError`s that occurred while trying to load automatically discovered linkers. These are never thrown from the call to this method as it makes every effort to recover from them and ignore the failing linkers. Returns:DynamicLinker the new dynamic Linker

public DynamicLinker createLinker()

Creates a new dynamic linker based on the current configuration. This method can be invoked more than once to create multiple dynamic linkers. Automatically discovered linkers are newly instantiated on every invocation of this method. It is allowed to change the factory's configuration between invocations. The method is not thread safe. After invocation, callers can invoke getAutoLoadingErrors() to retrieve a list of ServiceConfigurationErrors that occurred while trying to load automatically discovered linkers. These are never thrown from the call to this method as it makes every effort to recover from them and ignore the failing linkers.

Returns:DynamicLinker: the new dynamic Linker

discoverAutoLoadLinkers	back to summary
private List<GuardingDynamicLinker> discoverAutoLoadLinkers()

getAutoLoadingErrors back to summary

getAutoLoadingErrors	back to summary
public List<ServiceConfigurationError> getAutoLoadingErrors() Returns a list of `ServiceConfigurationError`s that were encountered while loading automatically discovered linkers during the last invocation of `createLinker()`. They can be any non-Dynalink specific service configuration issues, as well as some Dynalink-specific errors when an exporter that the factory tried to automatically load: did not have the runtime permission named `GuardingDynamicLinkerExporter#AUTOLOAD_PERMISSION_NAME` in a system with a security manager, or returned null from `GuardingDynamicLinkerExporter#get()`, or the list returned from `GuardingDynamicLinkerExporter#get()` had a null element. Returns:List<ServiceConfigurationError> an immutable list of encountered `ServiceConfigurationError`s. Can be empty.

public List<ServiceConfigurationError> getAutoLoadingErrors()

Returns a list of ServiceConfigurationErrors that were encountered while loading automatically discovered linkers during the last invocation of createLinker(). They can be any non-Dynalink specific service configuration issues, as well as some Dynalink-specific errors when an exporter that the factory tried to automatically load:

did not have the runtime permission named GuardingDynamicLinkerExporter#AUTOLOAD_PERMISSION_NAME in a system with a security manager, or
returned null from GuardingDynamicLinkerExporter#get(), or
the list returned from GuardingDynamicLinkerExporter#get() had a null element.

Returns:List<ServiceConfigurationError>: an immutable list of encountered ServiceConfigurationErrors. Can be empty.

getThreadContextClassLoader	back to summary
private static ClassLoader getThreadContextClassLoader() Annotations @SuppressWarnings:removal

requireNonNullElements	back to summary
private static <T> List<T> requireNonNullElements(final List<T> list, final Supplier<String> msgSupplier)

setAutoConversionStrategy back to summary

setAutoConversionStrategy	back to summary
public void setAutoConversionStrategy(final MethodTypeConversionStrategy autoConversionStrategy) Sets an object representing the conversion strategy for automatic type conversions. After `LinkerServices#asType(MethodHandle, MethodType)` has applied all custom conversions to a method handle, it still needs to effect `method invocation conversions` that can usually be automatically applied as per `MethodHandle#asType(MethodType)`. However, sometimes language runtimes will want to customize even those conversions for their own call sites. A typical example is allowing unboxing of null return values, which is by default prohibited by ordinary `MethodHandles.asType()`. In this case, a language runtime can install its own custom automatic conversion strategy, that can deal with null values. Note that when the strategy's `MethodTypeConversionStrategy#asType(MethodHandle, MethodType)` is invoked, the custom language conversions will already have been applied to the method handle, so by design the difference between the handle's current method type and the desired final type will always only be ones that can be subjected to method invocation conversions. The strategy also doesn't need to invoke a final `MethodHandle.asType()` as that will be done internally as the final step. Parameters autoConversionStrategy:MethodTypeConversionStrategy the strategy for applying method invocation conversions for the linker created by this factory. Can be null for no custom strategy.

public void setAutoConversionStrategy(final MethodTypeConversionStrategy autoConversionStrategy)

Sets an object representing the conversion strategy for automatic type conversions. After LinkerServices#asType(MethodHandle, MethodType) has applied all custom conversions to a method handle, it still needs to effect method invocation conversions that can usually be automatically applied as per MethodHandle#asType(MethodType). However, sometimes language runtimes will want to customize even those conversions for their own call sites. A typical example is allowing unboxing of null return values, which is by default prohibited by ordinary MethodHandles.asType(). In this case, a language runtime can install its own custom automatic conversion strategy, that can deal with null values. Note that when the strategy's MethodTypeConversionStrategy#asType(MethodHandle, MethodType) is invoked, the custom language conversions will already have been applied to the method handle, so by design the difference between the handle's current method type and the desired final type will always only be ones that can be subjected to method invocation conversions. The strategy also doesn't need to invoke a final MethodHandle.asType() as that will be done internally as the final step.

Parameters

autoConversionStrategy:MethodTypeConversionStrategy: the strategy for applying method invocation conversions for the linker created by this factory. Can be null for no custom strategy.

setClassLoader back to summary

setClassLoader	back to summary
public void setClassLoader(final ClassLoader classLoader) Sets the class loader for automatic discovery of available guarding dynamic linkers. `GuardingDynamicLinkerExporter` implementations available through this class loader will be automatically instantiated using the `ServiceLoader` mechanism and the linkers they provide will be incorporated into `DynamicLinker`s that this factory creates. This allows for cross-language interoperability where call sites belonging to this language runtime can be linked by linkers from these automatically discovered runtimes if their native objects are passed to this runtime. If class loader is not set explicitly by invoking this method, then the thread context class loader of the thread invoking `createLinker()` will be used. If this method is invoked explicitly with null then `ServiceLoader#loadInstalled(Class)` will be used to load the linkers. Parameters classLoader:ClassLoader the class loader used for the automatic discovery of available linkers.

public void setClassLoader(final ClassLoader classLoader)

Sets the class loader for automatic discovery of available guarding dynamic linkers. GuardingDynamicLinkerExporter implementations available through this class loader will be automatically instantiated using the ServiceLoader mechanism and the linkers they provide will be incorporated into DynamicLinkers that this factory creates. This allows for cross-language interoperability where call sites belonging to this language runtime can be linked by linkers from these automatically discovered runtimes if their native objects are passed to this runtime. If class loader is not set explicitly by invoking this method, then the thread context class loader of the thread invoking createLinker() will be used. If this method is invoked explicitly with null then ServiceLoader#loadInstalled(Class) will be used to load the linkers.

Parameters

classLoader:ClassLoader: the class loader used for the automatic discovery of available linkers.

setFallbackLinkers back to summary

setFallbackLinkers	back to summary
public void setFallbackLinkers(final List<? extends GuardingDynamicLinker> fallbackLinkers) Sets the fallback guarding dynamic linkers. These linkers will be consulted last by the resulting dynamic linker when it is linking call sites, after any autodiscovered and prioritized linkers. If the factory also autodiscovers a linker class matching one of the fallback linkers, the autodiscovered class will be ignored and the explicit fallback instance will be used. Parameters fallbackLinkers:List<? extends GuardingDynamicLinker> the list of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of `BeansLinker` to serve as the default fallback linker. Exceptions NullPointerException: if any of the list elements are null.

public void setFallbackLinkers(final List<? extends GuardingDynamicLinker> fallbackLinkers)

Sets the fallback guarding dynamic linkers. These linkers will be consulted last by the resulting dynamic linker when it is linking call sites, after any autodiscovered and prioritized linkers. If the factory also autodiscovers a linker class matching one of the fallback linkers, the autodiscovered class will be ignored and the explicit fallback instance will be used.

Parameters

fallbackLinkers:List<? extends GuardingDynamicLinker>: the list of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of BeansLinker to serve as the default fallback linker.

Exceptions

NullPointerException:: if any of the list elements are null.

setFallbackLinkers back to summary

setFallbackLinkers	back to summary
public void setFallbackLinkers(final GuardingDynamicLinker... fallbackLinkers) Sets the fallback guarding dynamic linkers. Identical to calling `setFallbackLinkers(List)` with `Arrays.asList(fallbackLinkers)`. Parameters fallbackLinkers:GuardingDynamicLinker[] an array of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of `BeansLinker` to serve as the default fallback linker. Exceptions NullPointerException: if any of the array elements are null.

public void setFallbackLinkers(final GuardingDynamicLinker... fallbackLinkers)

Sets the fallback guarding dynamic linkers. Identical to calling setFallbackLinkers(List) with Arrays.asList(fallbackLinkers).

Parameters

fallbackLinkers:GuardingDynamicLinker[]: an array of fallback linkers. Can be empty to indicate the caller wishes to set no fallback linkers. Note that if this method is not invoked explicitly or is passed null, then the factory will create an instance of BeansLinker to serve as the default fallback linker.

Exceptions

NullPointerException:: if any of the array elements are null.

setInternalObjectsFilter back to summary

setInternalObjectsFilter	back to summary
public void setInternalObjectsFilter(final MethodHandleTransformer internalObjectsFilter) Sets a method handle transformer that is supposed to act as the implementation of `LinkerServices#filterInternalObjects(MethodHandle)` for linker services of dynamic linkers created by this factory. Some language runtimes can have internal objects that should not escape their scope. They can add a transformer here that will modify the method handle so that any parameters that can receive potentially internal language runtime objects will have a filter added on them to prevent them from escaping, potentially by wrapping them. The transformer can also potentially add an unwrapping filter to the return value. `DefaultInternalObjectFilter` is provided as a convenience class for easily creating such filtering transformers. Parameters internalObjectsFilter:MethodHandleTransformer a method handle transformer filtering out internal objects, or null.

public void setInternalObjectsFilter(final MethodHandleTransformer internalObjectsFilter)

Sets a method handle transformer that is supposed to act as the implementation of LinkerServices#filterInternalObjects(MethodHandle) for linker services of dynamic linkers created by this factory. Some language runtimes can have internal objects that should not escape their scope. They can add a transformer here that will modify the method handle so that any parameters that can receive potentially internal language runtime objects will have a filter added on them to prevent them from escaping, potentially by wrapping them. The transformer can also potentially add an unwrapping filter to the return value. DefaultInternalObjectFilter is provided as a convenience class for easily creating such filtering transformers.

Parameters

internalObjectsFilter:MethodHandleTransformer: a method handle transformer filtering out internal objects, or null.

setPrelinkTransformer back to summary

setPrelinkTransformer	back to summary
public void setPrelinkTransformer(final GuardedInvocationTransformer prelinkTransformer) Set the pre-link transformer. This is a `GuardedInvocationTransformer` that will get the final chance to modify the guarded invocation after it has been created by a component linker and before the dynamic linker links it into the call site. It is normally used to adapt the return value type of the invocation to the type of the call site. When not set explicitly, a default pre-link transformer will be used that simply calls `GuardedInvocation#asType(LinkerServices, MethodType)`. Customized pre-link transformers are rarely needed; they are mostly used as a building block for implementing advanced techniques such as code deoptimization strategies. Parameters prelinkTransformer:GuardedInvocationTransformer the pre-link transformer for the dynamic linker. Can be null to have the factory use the default transformer.

public void setPrelinkTransformer(final GuardedInvocationTransformer prelinkTransformer)

Set the pre-link transformer. This is a GuardedInvocationTransformer that will get the final chance to modify the guarded invocation after it has been created by a component linker and before the dynamic linker links it into the call site. It is normally used to adapt the return value type of the invocation to the type of the call site. When not set explicitly, a default pre-link transformer will be used that simply calls GuardedInvocation#asType(LinkerServices, MethodType). Customized pre-link transformers are rarely needed; they are mostly used as a building block for implementing advanced techniques such as code deoptimization strategies.

Parameters

prelinkTransformer:GuardedInvocationTransformer: the pre-link transformer for the dynamic linker. Can be null to have the factory use the default transformer.

setPrioritizedLinker back to summary

setPrioritizedLinker	back to summary
public void setPrioritizedLinker(final GuardingDynamicLinker prioritizedLinker) Sets a single prioritized linker. Identical to calling `setPrioritizedLinkers(List)` with a single-element list. Parameters prioritizedLinker:GuardingDynamicLinker the single prioritized linker. Must not be null. Exceptions NullPointerException: if null is passed.

public void setPrioritizedLinker(final GuardingDynamicLinker prioritizedLinker)

Sets a single prioritized linker. Identical to calling setPrioritizedLinkers(List) with a single-element list.

Parameters

prioritizedLinker:GuardingDynamicLinker: the single prioritized linker. Must not be null.

Exceptions

NullPointerException:: if null is passed.

setPrioritizedLinkers	back to summary
public void setPrioritizedLinkers(final List<? extends GuardingDynamicLinker> prioritizedLinkers) Sets the prioritized guarding dynamic linkers. Language runtimes using Dynalink will usually have at least one linker for their own language. These linkers will be consulted first by the resulting dynamic linker when it is linking call sites, before any autodiscovered and fallback linkers. If the factory also autodiscovers a linker class matching one of the prioritized linkers, the autodiscovered class will be ignored and the explicit prioritized instance will be used. Parameters prioritizedLinkers:List<? extends GuardingDynamicLinker> the list of prioritized linkers. Can be null. Exceptions NullPointerException: if any of the list elements are null.

setPrioritizedLinkers

back to summary

public void setPrioritizedLinkers(final List<? extends GuardingDynamicLinker> prioritizedLinkers)

Sets the prioritized guarding dynamic linkers. Language runtimes using Dynalink will usually have at least one linker for their own language. These linkers will be consulted first by the resulting dynamic linker when it is linking call sites, before any autodiscovered and fallback linkers. If the factory also autodiscovers a linker class matching one of the prioritized linkers, the autodiscovered class will be ignored and the explicit prioritized instance will be used.

Parameters

prioritizedLinkers:List<? extends GuardingDynamicLinker>: the list of prioritized linkers. Can be null.

Exceptions

NullPointerException:: if any of the list elements are null.

setPrioritizedLinkers back to summary

setPrioritizedLinkers	back to summary
public void setPrioritizedLinkers(final GuardingDynamicLinker... prioritizedLinkers) Sets the prioritized guarding dynamic linkers. Identical to calling `setPrioritizedLinkers(List)` with `Arrays.asList(prioritizedLinkers)`. Parameters prioritizedLinkers:GuardingDynamicLinker[] an array of prioritized linkers. Can be null. Exceptions NullPointerException: if any of the array elements are null.

public void setPrioritizedLinkers(final GuardingDynamicLinker... prioritizedLinkers)

Sets the prioritized guarding dynamic linkers. Identical to calling setPrioritizedLinkers(List) with Arrays.asList(prioritizedLinkers).

Parameters

prioritizedLinkers:GuardingDynamicLinker[]: an array of prioritized linkers. Can be null.

Exceptions

NullPointerException:: if any of the array elements are null.

setSyncOnRelink back to summary

setSyncOnRelink	back to summary
public void setSyncOnRelink(final boolean syncOnRelink) Sets whether the dynamic linker created by this factory will invoke `MutableCallSite#syncAll(MutableCallSite[])` after a call site is relinked. Defaults to false. You probably want to set it to true if your runtime supports multithreaded execution of dynamically linked code. Parameters syncOnRelink:boolean true for invoking sync on relink, false otherwise.

public void setSyncOnRelink(final boolean syncOnRelink)

Sets whether the dynamic linker created by this factory will invoke MutableCallSite#syncAll(MutableCallSite[]) after a call site is relinked. Defaults to false. You probably want to set it to true if your runtime supports multithreaded execution of dynamically linked code.

Parameters

syncOnRelink:boolean: true for invoking sync on relink, false otherwise.

setUnstableRelinkThreshold back to summary

setUnstableRelinkThreshold	back to summary
public void setUnstableRelinkThreshold(final int unstableRelinkThreshold) Sets the unstable relink threshold; the number of times a call site is relinked after which it will be considered unstable, and subsequent link requests for it will indicate this. Defaults to 8 when not set explicitly. Parameters unstableRelinkThreshold:int the new threshold. Must not be less than zero. The value of zero means that call sites will never be considered unstable. See Also `LinkRequest#isCallSiteUnstable()`

public void setUnstableRelinkThreshold(final int unstableRelinkThreshold)

Sets the unstable relink threshold; the number of times a call site is relinked after which it will be considered unstable, and subsequent link requests for it will indicate this. Defaults to 8 when not set explicitly.

Parameters

unstableRelinkThreshold:int: the new threshold. Must not be less than zero. The value of zero means that call sites will never be considered unstable.

See Also

LinkRequest#isCallSiteUnstable()

public final Class DynamicLinkerFactory

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