net.bytebuddy.agent.builder

Class AgentBuilder.DescriptionStrategy.SuperTypeLoading.Asynchronous

java.lang.Object

net.bytebuddy.agent.builder.AgentBuilder.DescriptionStrategy.SuperTypeLoading.Asynchronous

All Implemented Interfaces:

AgentBuilder.DescriptionStrategy

Enclosing class:

AgentBuilder.DescriptionStrategy.SuperTypeLoading

@HashCodeAndEqualsPlugin.Enhance
public static class AgentBuilder.DescriptionStrategy.SuperTypeLoading.Asynchronous
extends Object
implements AgentBuilder.DescriptionStrategy

A description strategy that enforces the loading of any super type of a type description but delegates the actual type description to another description strategy.

Note: This description strategy delegates class loading to another thread in order to enforce the instrumentation of any unloaded super type. This requires the executor service to supply at least as many threads as the deepest type hierarchy within the application minus one for the instrumented type as class loading blocks any thread until all of its super types are loaded. These threads are typically short lived which predestines the use of a Executors.newCachedThreadPool() without any upper bound for the maximum number of created threads.

Important: This strategy can dead-lock under two circumstances:

• Classes declare circularities: Under normal circumstances, such scenarios result in a ClassCircularityError but can result in dead-locks when using this instrumentation strategy.
• Class loaders declare custom locks: If a class loader locks another lock but itself during class loading, this lock cannot be released by this strategy.

For the above reasons, it is not recommended to use this strategy when the target class loader is unknown or if the target application might contain corrupt class files.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	AgentBuilder.DescriptionStrategy.SuperTypeLoading.Asynchronous.ThreadSwitchingClassLoadingDelegate A class loading delegate that delegates loading of the super type to another thread.

Nested classes/interfaces inherited from interface net.bytebuddy.agent.builder.AgentBuilder.DescriptionStrategy

AgentBuilder.DescriptionStrategy.Default, AgentBuilder.DescriptionStrategy.SuperTypeLoading

Constructor Summary

Constructors

Constructor and Description
Asynchronous(AgentBuilder.DescriptionStrategy delegate, ExecutorService executorService) Creates a new description strategy that enforces super type loading from another thread.

Method Summary

Modifier and Type	Method and Description
TypeDescription	apply(String typeName, Class<?> type, TypePool typePool, AgentBuilder.CircularityLock circularityLock, ClassLoader classLoader, JavaModule module) Describes the given type.
boolean	isLoadedFirst() Indicates if this description strategy makes use of loaded type information and yields a different type description if no loaded type is available.

Methods inherited from class java.lang.Object

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

Constructor Detail

Asynchronous

public Asynchronous(AgentBuilder.DescriptionStrategy delegate,
                    ExecutorService executorService)

Creates a new description strategy that enforces super type loading from another thread.

Parameters:

delegate - The delegate description strategy.

executorService - The executor service to use for loading super types.

Method Detail

isLoadedFirst

public boolean isLoadedFirst()

Indicates if this description strategy makes use of loaded type information and yields a different type description if no loaded type is available.

Specified by:

isLoadedFirst in interface AgentBuilder.DescriptionStrategy

Returns:

true if this description strategy prefers loaded type information when describing a type and only uses a type pool if loaded type information is not available.

apply

public TypeDescription apply(String typeName,
                             Class<?> type,
                             TypePool typePool,
                             AgentBuilder.CircularityLock circularityLock,
                             ClassLoader classLoader,
                             JavaModule module)

Describes the given type.

Specified by:

apply in interface AgentBuilder.DescriptionStrategy

Parameters:

typeName - The binary name of the type to describe.

type - The type that is being redefined, if a redefinition is applied or null if no redefined type is available.

typePool - The type pool to use for locating a type if required.

circularityLock - The currently used circularity lock.

classLoader - The type's class loader where null represents the bootstrap class loader.

module - The type's module or null if the current VM does not support modules.

Returns:

An appropriate type description.