net.bytebuddy.agent.builder

Enum AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory

java.lang.Object

java.lang.Enum<AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory>

net.bytebuddy.agent.builder.AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory

All Implemented Interfaces:

Serializable, Comparable<AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory>, ByteCodeAppender

Enclosing class:

AgentBuilder.LambdaInstrumentationStrategy

protected static enum AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory
extends Enum<AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory>
implements ByteCodeAppender

A factory for rewriting the JDK's java.lang.invoke.LambdaMetafactory methods for use with Byte Buddy. The code that is created by this factory is roughly equivalent to the following:

 public static CallSite metafactory(MethodHandles.Lookup caller,
                                    String interfaceMethodName,
                                    MethodType factoryType,
                                    MethodType interfaceMethodType,
                                    MethodHandle implementation,
                                    MethodType dynamicMethodType) throws Exception {
   boolean serializable = false;
   List<Class<?>> markerInterfaces = Collections.emptyList();
   List<MethodType> additionalBridges = Collections.emptyList();
   byte[] binaryRepresentation = (byte[]) ClassLoader.getSystemClassLoader().loadClass("net.bytebuddy.agent.builder.LambdaFactory").getDeclaredMethod("make",
     Object.class,
     String.class,
     Object.class,
     Object.class,
     Object.class,
     Object.class,
     boolean.class,
     List.class,
     List.class).invoke(null,
       caller,
       interfaceMethodName,
       factoryType,
       interfaceMethodType,
       implementation,
       dynamicMethodType,
       serializable,
       markerInterfaces,
       additionalBridges);
   Class<?> lambdaClass = ... // loading code
   return factoryType.parameterCount() == 0
     ? new ConstantCallSite(MethodHandles.constant(factoryType.returnType(), lambdaClass.getDeclaredConstructors()[0].newInstance()))
     : new ConstantCallSite(Lookup.IMPL_LOOKUP.findStatic(lambdaClass, "get$Lambda", factoryType));
 }
 

The code's preamble is adjusted for the alternative metafactory to ressemble the following:

 public static CallSite altMetafactory(MethodHandles.Lookup caller,
                                       String interfaceMethodName,
                                       MethodType factoryType,
                                       Object... argument) throws Exception {
   int flags = (Integer) argument[3];
   int index = 4;
   Class<?>[] markerInterface;
   if ((flags & 2) != 0) {
     int count = (Integer) argument[index++];
     markerInterface = new Class<?>[count];
     System.arraycopy(argument, index, markerInterface, 0, count);
     index += count;
   } else {
     markerInterface = new Class<?>[0];
   }
   MethodType[] additionalBridge;
   if ((flags & 2) != 0) {
     int count = (Integer) argument[index++];
     additionalBridge = new MethodType[count];
     System.arraycopy(argument, index, additionalBridge, 0, count);
   } else {
     additionalBridge = new MethodType[0];
   }
   MethodType interfaceMethodType = (MethodType) argument[0];
   MethodHandle implementation = (MethodHandle) argument[1];
   MethodType dynamicMethodType = (MethodType) argument[2];
   boolean serializable = (flags & 1) != 0;
   List<Class<?>> markerInterfaces = Arrays.asList(markerInterface);
   List<MethodType> additionalBridges = Arrays.asList(additionalBridge);
   // ... reminder of method as before
 }
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static interface	AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory.Loader A loader is responsible for loading a generated class file in the current VM.

Nested classes/interfaces inherited from interface net.bytebuddy.implementation.bytecode.ByteCodeAppender

ByteCodeAppender.Compound, ByteCodeAppender.Simple, ByteCodeAppender.Size

Enum Constant Summary

Enum Constants

Enum Constant and Description
ALTERNATIVE Implements the java.lang.invoke.LambdaMetafactory#altMetafactory method.
REGULAR Implements the java.lang.invoke.LambdaMetafactory#metafactory method.

Method Summary

Modifier and Type	Method and Description
ByteCodeAppender.Size	apply(MethodVisitor methodVisitor, Implementation.Context implementationContext, MethodDescription instrumentedMethod) Applies this byte code appender to a type creation process.
protected abstract void	onDispatch(MethodVisitor methodVisitor) Invoked upon dispatch.
static AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory	valueOf(String name) Returns the enum constant of this type with the specified name.
static AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory[]	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

REGULAR

public static final AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory REGULAR

Implements the java.lang.invoke.LambdaMetafactory#metafactory method.

ALTERNATIVE

public static final AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory ALTERNATIVE

Implements the java.lang.invoke.LambdaMetafactory#altMetafactory method.

Method Detail

values

public static AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory[] 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.LambdaMetafactoryFactory c : AgentBuilder.LambdaInstrumentationStrategy.LambdaMetafactoryFactory.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.LambdaMetafactoryFactory valueOf(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:

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

NullPointerException - if the argument is null

apply

public ByteCodeAppender.Size apply(MethodVisitor methodVisitor,
                                   Implementation.Context implementationContext,
                                   MethodDescription instrumentedMethod)

Applies this byte code appender to a type creation process.

Specified by:

apply in interface ByteCodeAppender

Parameters:

methodVisitor - The method visitor to which the byte code appender writes its code to.

implementationContext - The implementation context of the current type creation process.

instrumentedMethod - The method that is the target of the instrumentation.

Returns:

The required size for the applied byte code to run.

onDispatch

protected abstract void onDispatch(MethodVisitor methodVisitor)

Invoked upon dispatch. As a result, all values that are presented to Byte Buddy's code generator must be arranged on the stack.

Parameters:

methodVisitor - The method visitor to use.