Package net.bytebuddy.agent.builder

Enum AgentBuilder.LambdaInstrumentationStrategy

java.lang.Object

java.lang.Enum<AgentBuilder.LambdaInstrumentationStrategy>

net.bytebuddy.agent.builder.AgentBuilder.LambdaInstrumentationStrategy

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<AgentBuilder.LambdaInstrumentationStrategy>

Enclosing interface:

AgentBuilder

public static enum AgentBuilder.LambdaInstrumentationStrategy
extends java.lang.Enum<AgentBuilder.LambdaInstrumentationStrategy>

Implements the instrumentation of the LambdaMetafactory if this feature is enabled.

Warning: This feature is not recommended for production systems but only for experiments or debugging purposes. It might no longer work in a future release and makes assumptions over JVM-internal API.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AgentBuilder.LambdaInstrumentationStrategy.LambdaInstanceFactory	A factory that creates instances that represent lambda expressions.
protected static class	AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory	A factory for rewriting the JDK's java.lang.invoke.LambdaMetafactory methods for use with Byte Buddy.

Enum Constant Summary

Enum Constants

Enum Constant	Description
DISABLED	A strategy that does not instrument the LambdaMetafactory.
ENABLED	A strategy that enables instrumentation of the LambdaMetafactory if such a factory exists on the current VM.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	LambdaInstrumentationStrategy()

Method Summary

Modifier and Type	Method	Description
protected abstract void	apply(ByteBuddy byteBuddy, java.lang.instrument.Instrumentation instrumentation, java.lang.instrument.ClassFileTransformer classFileTransformer)	Applies a transformation to lambda instances if applicable.
boolean	isEnabled()	Indicates if this strategy enables instrumentation of the LambdaMetafactory.
protected abstract boolean	isInstrumented(java.lang.Class<?> type)	Validates if the supplied class is instrumented.
static AgentBuilder.LambdaInstrumentationStrategy	of(boolean enabled)	Returns an enabled lambda instrumentation strategy for true.
static void	release(java.lang.instrument.ClassFileTransformer classFileTransformer, java.lang.instrument.Instrumentation instrumentation)	Releases the supplied class file transformer when it was built with AgentBuilder.with(LambdaInstrumentationStrategy) enabled.
static AgentBuilder.LambdaInstrumentationStrategy	valueOf(java.lang.String name)	Returns the enum constant of this type with the specified name.
static AgentBuilder.LambdaInstrumentationStrategy[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

ENABLED

public static final AgentBuilder.LambdaInstrumentationStrategy ENABLED

A strategy that enables instrumentation of the LambdaMetafactory if such a factory exists on the current VM. Classes representing lambda expressions that are created by Byte Buddy are fully compatible to those created by the JVM and can be serialized or deserialized to one another. The classes do however show a few differences:

• Byte Buddy's classes are public with a public executing transformer. Doing so, it is not necessary to instantiate a non-capturing lambda expression by reflection. This is done because Byte Buddy is not necessarily capable of using reflection due to an active security manager.
• Byte Buddy's classes are not marked as synthetic as an agent builder does not instrument synthetic classes by default.

DISABLED

public static final AgentBuilder.LambdaInstrumentationStrategy DISABLED

A strategy that does not instrument the LambdaMetafactory.

Constructor Detail

LambdaInstrumentationStrategy

private LambdaInstrumentationStrategy()

Method Detail

values

public static AgentBuilder.LambdaInstrumentationStrategy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (AgentBuilder.LambdaInstrumentationStrategy c : AgentBuilder.LambdaInstrumentationStrategy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static AgentBuilder.LambdaInstrumentationStrategy valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

release

public static void release(java.lang.instrument.ClassFileTransformer classFileTransformer,
                           java.lang.instrument.Instrumentation instrumentation)

Releases the supplied class file transformer when it was built with AgentBuilder.with(LambdaInstrumentationStrategy) enabled. Subsequently, the class file transformer is no longer applied when a class that represents a lambda expression is created.

Parameters:

classFileTransformer - The class file transformer to release.

instrumentation - The instrumentation instance that is used to potentially rollback the instrumentation of the LambdaMetafactory.

of

public static AgentBuilder.LambdaInstrumentationStrategy of(boolean enabled)

Returns an enabled lambda instrumentation strategy for true.

Parameters:

enabled - If lambda instrumentation should be enabled.

Returns:

true if the returned strategy should be enabled.

apply

protected abstract void apply(ByteBuddy byteBuddy,
                              java.lang.instrument.Instrumentation instrumentation,
                              java.lang.instrument.ClassFileTransformer classFileTransformer)

Applies a transformation to lambda instances if applicable.

Parameters:

byteBuddy - The Byte Buddy instance to use.

instrumentation - The instrumentation instance for applying a redefinition.

classFileTransformer - The class file transformer to apply.

isEnabled

public boolean isEnabled()

Indicates if this strategy enables instrumentation of the LambdaMetafactory.

Returns:

true if this strategy is enabled.

isInstrumented

protected abstract boolean isInstrumented(@MaybeNull
                                          java.lang.Class<?> type)

Validates if the supplied class is instrumented. For lambda types (which are loaded by anonymous class loader), this method should return false if lambda instrumentation is disabled.

Parameters:

type - The redefined type or null if no such type exists.

Returns:

true if the supplied type should be instrumented according to this strategy.