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Byte Buddy is a Java library for creating Java classes at run time.
This artifact is a build of Byte Buddy with a remaining dependency onto ASM.
You should never depend on this module without repackaging Byte Buddy and ASM into your own namespace.
package net.bytebuddy.utility;
import net.bytebuddy.description.field.FieldDescription;
import net.bytebuddy.description.method.MethodDescription;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.description.type.TypeList;
import net.bytebuddy.implementation.bytecode.StackManipulation;
import net.bytebuddy.implementation.bytecode.constant.MethodHandleConstant;
import net.bytebuddy.implementation.bytecode.constant.MethodTypeConstant;
import org.objectweb.asm.Handle;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
/**
* Returns a Java instance of an object that has a special meaning to the Java virtual machine and that is not
* available to Java in versions 6.
*/
public interface JavaInstance {
/**
* Returns the represented instance as a constant pool value.
*
* @return The constant pool value in a format that can be written by ASM.
*/
Object asConstantPoolValue();
/**
* Returns the instance as loadable onto the operand stack.
*
* @return A stack manipulation that loads the represented value onto the operand stack.
*/
StackManipulation asStackManipulation();
/**
* Returns a description of the type of the represented instance or at least a stub.
*
* @return A description of the type of the represented instance or at least a stub.
*/
TypeDescription getInstanceType();
/**
* Represents a {@code java.lang.invoke.MethodType} object.
*/
class MethodType implements JavaInstance {
/**
* A dispatcher for extracting information from a {@code java.lang.invoke.MethodType} instance.
*/
private static final Dispatcher DISPATCHER;
/*
* Locates a dispatcher depending on the feature set of the currently running JVM.
*/
static {
Dispatcher dispatcher;
try {
Class methodType = JavaType.METHOD_TYPE.load();
dispatcher = new Dispatcher.ForModernVm(methodType.getDeclaredMethod("returnType"), methodType.getDeclaredMethod("parameterArray"));
} catch (RuntimeException exception) {
throw exception;
} catch (Exception ignored) {
dispatcher = Dispatcher.ForLegacyVm.INSTANCE;
}
DISPATCHER = dispatcher;
}
/**
* The return type of this method type.
*/
private final TypeDescription returnType;
/**
* The parameter types of this method type.
*/
private final List parameterTypes;
/**
* Creates a method type for the given types.
*
* @param returnType The return type of the method type.
* @param parameterTypes The parameter types of the method type.
*/
protected MethodType(TypeDescription returnType, List parameterTypes) {
this.returnType = returnType;
this.parameterTypes = parameterTypes;
}
/**
* Returns a method type representation of a loaded {@code MethodType} object.
*
* @param methodType A method type object to represent as a {@link JavaInstance}.
* @return The method type represented as a {@code JavaInstance}.
*/
public static MethodType of(Object methodType) {
if (!JavaType.METHOD_TYPE.getTypeStub().isInstance(methodType)) {
throw new IllegalArgumentException("Expected method type object: " + methodType);
}
return of(DISPATCHER.returnType(methodType), DISPATCHER.parameterArray(methodType));
}
/**
* Returns a method type description of the given return type and parameter types.
*
* @param returnType The return type to represent.
* @param parameterType The parameter types to represent.
* @return A method type of the given return type and parameter types.
*/
public static MethodType of(Class returnType, Class... parameterType) {
return of(new TypeDescription.ForLoadedType(returnType), new TypeList.ForLoadedTypes(parameterType));
}
/**
* Returns a method type description of the given return type and parameter types.
*
* @param returnType The return type to represent.
* @param parameterTypes The parameter types to represent.
* @return A method type of the given return type and parameter types.
*/
public static MethodType of(TypeDescription returnType, List parameterTypes) {
return new MethodType(returnType, parameterTypes);
}
/**
* Returns a method type description of the given method.
*
* @param method The method to extract the method type from.
* @return The method type of the given method.
*/
public static MethodType of(Method method) {
return of(new MethodDescription.ForLoadedMethod(method));
}
/**
* Returns a method type description of the given constructor.
*
* @param constructor The constructor to extract the method type from.
* @return The method type of the given constructor.
*/
public static MethodType of(Constructor constructor) {
return of(new MethodDescription.ForLoadedConstructor(constructor));
}
/**
* Returns a method type description of the given method.
*
* @param methodDescription The method to extract the method type from.
* @return The method type of the given method.
*/
public static MethodType of(MethodDescription methodDescription) {
return new MethodType(methodDescription.getReturnType().asErasure(), methodDescription.getParameters().asTypeList().asErasures());
}
/**
* Returns a method type for a setter of the given field.
*
* @param field The field to extract a setter type for.
* @return The type of a setter for the given field.
*/
public static MethodType ofSetter(Field field) {
return ofSetter(new FieldDescription.ForLoadedField(field));
}
/**
* Returns a method type for a setter of the given field.
*
* @param fieldDescription The field to extract a setter type for.
* @return The type of a setter for the given field.
*/
public static MethodType ofSetter(FieldDescription fieldDescription) {
return new MethodType(TypeDescription.VOID, Collections.singletonList(fieldDescription.getType().asErasure()));
}
/**
* Returns a method type for a getter of the given field.
*
* @param field The field to extract a getter type for.
* @return The type of a getter for the given field.
*/
public static MethodType ofGetter(Field field) {
return ofGetter(new FieldDescription.ForLoadedField(field));
}
/**
* Returns a method type for a getter of the given field.
*
* @param fieldDescription The field to extract a getter type for.
* @return The type of a getter for the given field.
*/
public static MethodType ofGetter(FieldDescription fieldDescription) {
return new MethodType(fieldDescription.getType().asErasure(), Collections.emptyList());
}
/**
* Returns a method type for the given constant.
*
* @param instance The constant for which a constant method type should be created.
* @return A method type for the given constant.
*/
public static MethodType ofConstant(Object instance) {
return ofConstant(instance.getClass());
}
/**
* Returns a method type for the given constant type.
*
* @param type The constant type for which a constant method type should be created.
* @return A method type for the given constant type.
*/
public static MethodType ofConstant(Class type) {
return ofConstant(new TypeDescription.ForLoadedType(type));
}
/**
* Returns a method type for the given constant type.
*
* @param typeDescription The constant type for which a constant method type should be created.
* @return A method type for the given constant type.
*/
public static MethodType ofConstant(TypeDescription typeDescription) {
return new MethodType(typeDescription, Collections.emptyList());
}
/**
* Returns the return type of this method type.
*
* @return The return type of this method type.
*/
public TypeDescription getReturnType() {
return returnType;
}
/**
* Returns the parameter types of this method type.
*
* @return The parameter types of this method type.
*/
public List getParameterTypes() {
return new ArrayList(parameterTypes);
}
@Override
public Object asConstantPoolValue() {
StringBuilder stringBuilder = new StringBuilder("(");
for (TypeDescription parameterType : getParameterTypes()) {
stringBuilder.append(parameterType.getDescriptor());
}
return Type.getMethodType(stringBuilder.append(")").append(getReturnType().getDescriptor()).toString());
}
@Override
public StackManipulation asStackManipulation() {
return MethodTypeConstant.of(this);
}
@Override
public TypeDescription getInstanceType() {
return JavaType.METHOD_TYPE.getTypeStub();
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
MethodType that = (MethodType) other;
return parameterTypes.equals(that.parameterTypes) && returnType.equals(that.returnType);
}
@Override
public int hashCode() {
int result = returnType.hashCode();
result = 31 * result + parameterTypes.hashCode();
return result;
}
@Override
public String toString() {
return "JavaInstance.MethodType{" +
"returnType=" + returnType +
", parameterTypes=" + parameterTypes +
'}';
}
/**
* A dispatcher for extracting information from a {@code java.lang.invoke.MethodType} instance.
*/
protected interface Dispatcher {
/**
* Extracts the return type of the supplied method type.
*
* @param methodType An instance of {@code java.lang.invoke.MethodType}.
* @return The return type that is described by the supplied instance.
*/
Class returnType(Object methodType);
/**
* Extracts the parameter types of the supplied method type.
*
* @param methodType An instance of {@code java.lang.invoke.MethodType}.
* @return The parameter types that are described by the supplied instance.
*/
Class[] parameterArray(Object methodType);
/**
* A dispatcher for virtual machines that are aware of the {@code java.lang.invoke.MethodType} type that was added in Java version 7.
*/
class ForModernVm implements Dispatcher {
/**
* A reference to {@code java.lang.invoke.MethodType#returnType}.
*/
private final Method returnType;
/**
* A reference to {@code java.lang.invoke.MethodType#returnType}.
*/
private final Method parameterArray;
/**
* Creates a new dispatcher for a modern JVM.
*
* @param returnType A reference to {@code java.lang.invoke.MethodType#returnType}.
* @param parameterArray A reference to {@code java.lang.invoke.MethodType#returnType}.
*/
protected ForModernVm(Method returnType, Method parameterArray) {
this.returnType = returnType;
this.parameterArray = parameterArray;
}
@Override
public Class returnType(Object methodType) {
try {
return (Class) returnType.invoke(methodType);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodType#returnType", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodType#returnType", exception.getCause());
}
}
@Override
public Class[] parameterArray(Object methodType) {
try {
return (Class[]) parameterArray.invoke(methodType);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodType#parameterArray", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodType#parameterArray", exception.getCause());
}
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
ForModernVm that = (ForModernVm) other;
return returnType.equals(that.returnType) && parameterArray.equals(that.parameterArray);
}
@Override
public int hashCode() {
int result = returnType.hashCode();
result = 31 * result + parameterArray.hashCode();
return result;
}
@Override
public String toString() {
return "JavaInstance.MethodType.Dispatcher.ForModernVm{" +
"returnType=" + returnType +
", parameterArray=" + parameterArray +
'}';
}
}
/**
* A dispatcher for virtual machines that are not aware of the {@code java.lang.invoke.MethodType} type that was added in Java version 7.
*/
enum ForLegacyVm implements Dispatcher {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public Class returnType(Object methodType) {
throw new IllegalStateException("Unsupported type for the current JVM: java.lang.invoke.MethodType");
}
@Override
public Class[] parameterArray(Object methodType) {
throw new IllegalStateException("Unsupported type for the current JVM: java.lang.invoke.MethodType");
}
@Override
public String toString() {
return "JavaInstance.MethodType.Dispatcher.ForLegacyVm." + name();
}
}
}
}
/**
* Represents a {@code java.lang.invoke.MethodHandle} object. Note that constant {@code MethodHandle}s cannot
* be represented within the constant pool of a Java class and can therefore not be represented as an instance of
* this representation order.
*/
class MethodHandle implements JavaInstance {
/**
* A dispatcher for receiving the type information that is represented by a {@code java.lang.invoke.MethodHandle} instance.
*/
private static final Dispatcher.Initializable DISPATCHER;
/*
* Locates a dispatcher depending on the feature set of the currently running JVM.
*/
static {
Dispatcher.Initializable dispatcher;
try {
Class methodHandleInfo = Class.forName("java.lang.invoke.MethodHandleInfo");
Class methodType = JavaType.METHOD_TYPE.load();
try {
dispatcher = new Dispatcher.ForModernVm(Class.forName("java.lang.invoke.MethodHandles").getDeclaredMethod("publicLookup"),
methodHandleInfo.getDeclaredMethod("getName"),
methodHandleInfo.getDeclaredMethod("getDeclaringClass"),
methodHandleInfo.getDeclaredMethod("getReferenceKind"),
methodHandleInfo.getDeclaredMethod("getMethodType"),
methodType.getDeclaredMethod("returnType"),
methodType.getDeclaredMethod("parameterArray"),
JavaType.METHOD_HANDLES_LOOKUP.load().getDeclaredMethod("revealDirect", JavaType.METHOD_HANDLE.load()));
} catch (RuntimeException exception) {
throw exception;
} catch (Exception ignored) {
dispatcher = new Dispatcher.ForIntermediateVm(Class.forName("java.lang.invoke.MethodHandles").getDeclaredMethod("publicLookup"),
methodHandleInfo.getDeclaredMethod("getName"),
methodHandleInfo.getDeclaredMethod("getDeclaringClass"),
methodHandleInfo.getDeclaredMethod("getReferenceKind"),
methodHandleInfo.getDeclaredMethod("getMethodType"),
methodType.getDeclaredMethod("returnType"),
methodType.getDeclaredMethod("parameterArray"),
methodHandleInfo.getDeclaredConstructor(JavaType.METHOD_HANDLE.load()));
}
} catch (RuntimeException exception) {
throw exception;
} catch (Exception ignored) {
dispatcher = Dispatcher.ForLegacyVm.INSTANCE;
}
DISPATCHER = dispatcher;
}
/**
* The handle type that is represented by this instance.
*/
private final HandleType handleType;
/**
* The owner type that is represented by this instance.
*/
private final TypeDescription ownerType;
/**
* The name that is represented by this instance.
*/
private final String name;
/**
* The return type that is represented by this instance.
*/
private final TypeDescription returnType;
/**
* The parameter types that is represented by this instance.
*/
private final List parameterTypes;
/**
* Creates a method handle representation.
*
* @param handleType The handle type that is represented by this instance.
* @param ownerType The owner type that is represented by this instance.
* @param name The name that is represented by this instance.
* @param returnType The return type that is represented by this instance.
* @param parameterTypes The parameter types that is represented by this instance.
*/
protected MethodHandle(HandleType handleType,
TypeDescription ownerType,
String name,
TypeDescription returnType,
List parameterTypes) {
this.handleType = handleType;
this.ownerType = ownerType;
this.name = name;
this.returnType = returnType;
this.parameterTypes = parameterTypes;
}
/**
* Creates a method handles representation of a loaded method handle which is analyzed using a public {@code MethodHandles.Lookup} object.
* A method handle can only be analyzed on virtual machines that support the corresponding API (Java 7+). For virtual machines before Java 8+,
* a method handle instance can only be analyzed by taking advantage of private APIs what might require a access context.
*
* @param methodHandle The loaded method handle to represent.
* @return A representation of the loaded method handle
*/
public static MethodHandle of(Object methodHandle) {
return of(methodHandle, DISPATCHER.publicLookup(), AccessController.getContext());
}
/**
* Creates a method handles representation of a loaded method handle which is analyzed using the given lookup context.
* A method handle can only be analyzed on virtual machines that support the corresponding API (Java 7+). For virtual machines before Java 8+,
* a method handle instance can only be analyzed by taking advantage of private APIs what might require a access context.
*
* @param methodHandle The loaded method handle to represent.
* @param lookup The lookup object to use for analyzing the method handle.
* @return A representation of the loaded method handle
*/
public static MethodHandle of(Object methodHandle, Object lookup) {
return of(methodHandle, lookup, AccessController.getContext());
}
/**
* Creates a method handles representation of a loaded method handle which is analyzed using a public {@code MethodHandles.Lookup} object.
* A method handle can only be analyzed on virtual machines that support the corresponding API (Java 7+). For virtual machines before Java 8+,
* a method handle instance can only be analyzed by taking advantage of private APIs what might require a access context.
*
* @param methodHandle The loaded method handle to represent.
* @param accessControlContext The access control context to be used for making private methods accessible when using Java 7.
* @return A representation of the loaded method handle
*/
public static MethodHandle of(Object methodHandle, AccessControlContext accessControlContext) {
return of(methodHandle, DISPATCHER.publicLookup(), accessControlContext);
}
/**
* Creates a method handles representation of a loaded method handle which is analyzed using the given lookup context.
* A method handle can only be analyzed on virtual machines that support the corresponding API (Java 7+). For virtual machines before Java 8+,
* a method handle instance can only be analyzed by taking advantage of private APIs what might require a access context.
*
* @param methodHandle The loaded method handle to represent.
* @param lookup The lookup object to use for analyzing the method handle.
* @param accessControlContext The access control context to be used for making private methods accessible when using Java 7.
* @return A representation of the loaded method handle
*/
public static MethodHandle of(Object methodHandle, Object lookup, AccessControlContext accessControlContext) {
if (!JavaType.METHOD_HANDLE.getTypeStub().isInstance(methodHandle)) {
throw new IllegalArgumentException("Expected method handle object: " + methodHandle);
} else if (!JavaType.METHOD_HANDLES_LOOKUP.getTypeStub().isInstance(lookup)) {
throw new IllegalArgumentException("Expected method handle lookup object: " + lookup);
}
Dispatcher dispatcher = DISPATCHER.initialize(accessControlContext);
Object methodHandleInfo = dispatcher.reveal(lookup, methodHandle);
Object methodType = dispatcher.getMethodType(methodHandleInfo);
return new MethodHandle(HandleType.of(dispatcher.getReferenceKind(methodHandleInfo)),
new TypeDescription.ForLoadedType(dispatcher.getDeclaringClass(methodHandleInfo)),
dispatcher.getName(methodHandleInfo),
new TypeDescription.ForLoadedType(dispatcher.returnType(methodType)),
new TypeList.ForLoadedTypes(dispatcher.parameterArray(methodType)));
}
/**
* Creates a method handle representation of the given method.
*
* @param method The method ro represent.
* @return A method handle representing the given method.
*/
public static MethodHandle of(Method method) {
return of(new MethodDescription.ForLoadedMethod(method));
}
/**
* Creates a method handle representation of the given constructor.
*
* @param constructor The constructor ro represent.
* @return A method handle representing the given constructor.
*/
public static MethodHandle of(Constructor constructor) {
return of(new MethodDescription.ForLoadedConstructor(constructor));
}
/**
* Creates a method handle representation of the given method.
*
* @param methodDescription The method ro represent.
* @return A method handle representing the given method.
*/
public static MethodHandle of(MethodDescription methodDescription) {
return new MethodHandle(HandleType.of(methodDescription),
methodDescription.getDeclaringType().asErasure(),
methodDescription.getInternalName(),
methodDescription.getReturnType().asErasure(),
methodDescription.getParameters().asTypeList().asErasures());
}
/**
* Creates a method handle representation of the given method for an explicit special method invocation of an otherwise virtual method.
*
* @param method The method ro represent.
* @param type The type on which the method is to be invoked on as a special method invocation.
* @return A method handle representing the given method as special method invocation.
*/
public static MethodHandle ofSpecial(Method method, Class type) {
return ofSpecial(new MethodDescription.ForLoadedMethod(method), new TypeDescription.ForLoadedType(type));
}
/**
* Creates a method handle representation of the given method for an explicit special method invocation of an otherwise virtual method.
*
* @param methodDescription The method ro represent.
* @param typeDescription The type on which the method is to be invoked on as a special method invocation.
* @return A method handle representing the given method as special method invocation.
*/
public static MethodHandle ofSpecial(MethodDescription methodDescription, TypeDescription typeDescription) {
if (!methodDescription.isSpecializableFor(typeDescription)) {
throw new IllegalArgumentException("Cannot specialize " + methodDescription + " for " + typeDescription);
}
return new MethodHandle(HandleType.ofSpecial(methodDescription),
typeDescription,
methodDescription.getInternalName(),
methodDescription.getReturnType().asErasure(),
methodDescription.getParameters().asTypeList().asErasures());
}
/**
* Returns a method handle for a setter of the given field.
*
* @param field The field to represent.
* @return A method handle for a setter of the given field.
*/
public static MethodHandle ofGetter(Field field) {
return ofGetter(new FieldDescription.ForLoadedField(field));
}
/**
* Returns a method handle for a setter of the given field.
*
* @param fieldDescription The field to represent.
* @return A method handle for a setter of the given field.
*/
public static MethodHandle ofGetter(FieldDescription fieldDescription) {
return new MethodHandle(HandleType.ofGetter(fieldDescription),
fieldDescription.getDeclaringType().asErasure(),
fieldDescription.getInternalName(),
fieldDescription.getType().asErasure(),
Collections.emptyList());
}
/**
* Returns a method handle for a getter of the given field.
*
* @param field The field to represent.
* @return A method handle for a getter of the given field.
*/
public static MethodHandle ofSetter(Field field) {
return ofSetter(new FieldDescription.ForLoadedField(field));
}
/**
* Returns a method handle for a getter of the given field.
*
* @param fieldDescription The field to represent.
* @return A method handle for a getter of the given field.
*/
public static MethodHandle ofSetter(FieldDescription fieldDescription) {
return new MethodHandle(HandleType.ofSetter(fieldDescription),
fieldDescription.getDeclaringType().asErasure(),
fieldDescription.getInternalName(),
TypeDescription.VOID,
Collections.singletonList(fieldDescription.getType().asErasure()));
}
@Override
public Object asConstantPoolValue() {
StringBuilder stringBuilder = new StringBuilder("(");
for (TypeDescription parameterType : getParameterTypes()) {
stringBuilder.append(parameterType.getDescriptor());
}
String descriptor = stringBuilder.append(")").append(getReturnType().getDescriptor()).toString();
return new Handle(getHandleType().getIdentifier(), getOwnerType().getInternalName(), getName(), descriptor);
}
@Override
public StackManipulation asStackManipulation() {
return MethodHandleConstant.of(this);
}
@Override
public TypeDescription getInstanceType() {
return JavaType.METHOD_HANDLE.getTypeStub();
}
/**
* Returns the handle type represented by this instance.
*
* @return The handle type represented by this instance.
*/
public HandleType getHandleType() {
return handleType;
}
/**
* Returns the owner type of this instance.
*
* @return The owner type of this instance.
*/
public TypeDescription getOwnerType() {
return ownerType;
}
/**
* Returns the name represented by this instance.
*
* @return The name represented by this instance.
*/
public String getName() {
return name;
}
/**
* Returns the return type represented by this instance.
*
* @return The return type represented by this instance.
*/
public TypeDescription getReturnType() {
return returnType;
}
/**
* Returns the parameter types represented by this instance.
*
* @return The parameter types represented by this instance.
*/
public List getParameterTypes() {
return new ArrayList(parameterTypes);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
MethodHandle aDefault = (MethodHandle) other;
return handleType == aDefault.handleType
&& name.equals(aDefault.name)
&& ownerType.equals(aDefault.ownerType)
&& parameterTypes.equals(aDefault.parameterTypes)
&& returnType.equals(aDefault.returnType);
}
@Override
public int hashCode() {
int result = handleType.hashCode();
result = 31 * result + ownerType.hashCode();
result = 31 * result + name.hashCode();
result = 31 * result + returnType.hashCode();
result = 31 * result + parameterTypes.hashCode();
return result;
}
@Override
public String toString() {
return "JavaInstance.MethodHandle{" +
"handleType=" + handleType +
", ownerType=" + ownerType +
", name='" + name + '\'' +
", returnType=" + returnType +
", parameterTypes=" + parameterTypes +
'}';
}
/**
* A dispatcher for analyzing a {@code java.lang.invoke.MethodHandle} instance.
*/
protected interface Dispatcher {
/**
* Reveals a method handle's information object.
*
* @param lookup The lookup to be used for introspecting the instance.
* @param methodHandle The method handle to be introspected.
* @return The {@code java.lang.invoke.MethodHandleInfo} object that describes the instance.
*/
Object reveal(Object lookup, Object methodHandle);
/**
* Returns a method handle info's method type.
*
* @param methodHandleInfo The method handle info to introspect.
* @return The {@link java.lang.invoke.MethodType} instance representing the method handle's type.
*/
Object getMethodType(Object methodHandleInfo);
/**
* Returns the reference kind of the supplied method handle info.
*
* @param methodHandleInfo The method handle to be introspected.
* @return The method handle info's reference type.
*/
int getReferenceKind(Object methodHandleInfo);
/**
* Returns the declaring class of the supplied method handle info.
*
* @param methodHandleInfo The method handle to be introspected.
* @return The method handle info's declaring class.
*/
Class getDeclaringClass(Object methodHandleInfo);
/**
* Returns the method name of the supplied method handle info.
*
* @param methodHandleInfo The method handle to be introspected.
* @return The method handle info's method name.
*/
String getName(Object methodHandleInfo);
/**
* Returns the return type of the supplied method type.
*
* @param methodType The method type to be introspected.
* @return The method type's return type.
*/
Class returnType(Object methodType);
/**
* Returns the parameter types of the supplied method type.
*
* @param methodType The method type to be introspected.
* @return The method type's parameter types.
*/
List> parameterArray(Object methodType);
/**
* An initializable version of a dispatcher that is not yet made accessible.
*/
interface Initializable {
/**
* Initializes the dispatcher, if required.
*
* @param accessControlContext The access control context to be used for introspecting private APIs, if required.
* @return The initialized dispatcher.
*/
Dispatcher initialize(AccessControlContext accessControlContext);
/**
* Returns a public {@code java.lang.invoke.MethodHandles.Lookup} instance.
*
* @return A public {@code java.lang.invoke.MethodHandles.Lookup} instance.
*/
Object publicLookup();
}
/**
* An abstract base impleementation of a dispatcher.
*/
abstract class AbstractBase implements Dispatcher, Initializable {
/**
* A reference to {@code java.lang.invoke.MethodHandles#publicLookup}.
*/
protected final Method publicLookup;
/**
* A reference to {@code java.lang.invoke.MethodHandleInfo#getName}.
*/
protected final Method getName;
/**
* A reference to {@code java.lang.invoke.MethodHandleInfo#getDeclaringClass}.
*/
protected final Method getDeclaringClass;
/**
* A reference to {@code java.lang.invoke.MethodHandleInfo#getReferenceKind}.
*/
protected final Method getReferenceKind;
/**
* A reference to {@code java.lang.invoke.MethodHandleInfo#getMethodType}.
*/
protected final Method getMethodType;
/**
* A reference to {@code java.lang.invoke.MethodType#returnType}.
*/
protected final Method returnType;
/**
* A reference to {@code java.lang.invoke.MethodType#parameterArray}.
*/
protected final Method parameterArray;
/**
* Creates a legal dispatcher.
*
* @param publicLookup A reference to {@code java.lang.invoke.MethodHandles#publicLookup}.
* @param getName A reference to {@code java.lang.invoke.MethodHandleInfo#getName}.
* @param getDeclaringClass A reference to {@code java.lang.invoke.MethodHandleInfo#getDeclaringClass}.
* @param getReferenceKind A reference to {@code java.lang.invoke.MethodHandleInfo#getReferenceKind}.
* @param getMethodType A reference to {@code java.lang.invoke.MethodHandleInfo#getMethodType}.
* @param returnType A reference to {@code java.lang.invoke.MethodType#returnType}.
* @param parameterArray A reference to {@code java.lang.invoke.MethodType#parameterArray}.
*/
protected AbstractBase(Method publicLookup,
Method getName,
Method getDeclaringClass,
Method getReferenceKind,
Method getMethodType,
Method returnType,
Method parameterArray) {
this.publicLookup = publicLookup;
this.getName = getName;
this.getDeclaringClass = getDeclaringClass;
this.getReferenceKind = getReferenceKind;
this.getMethodType = getMethodType;
this.returnType = returnType;
this.parameterArray = parameterArray;
}
@Override
public Object publicLookup() {
try {
return publicLookup.invoke(null);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandles#publicLookup", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandles#publicLookup", exception.getCause());
}
}
@Override
public Object getMethodType(Object methodHandleInfo) {
try {
return getMethodType.invoke(methodHandleInfo);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandleInfo#getMethodType", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandleInfo#getMethodType", exception.getCause());
}
}
@Override
public int getReferenceKind(Object methodHandleInfo) {
try {
return (Integer) getReferenceKind.invoke(methodHandleInfo);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandleInfo#getReferenceKind", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandleInfo#getReferenceKind", exception.getCause());
}
}
@Override
public Class getDeclaringClass(Object methodHandleInfo) {
try {
return (Class) getDeclaringClass.invoke(methodHandleInfo);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandleInfo#getDeclaringClass", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandleInfo#getDeclaringClass", exception.getCause());
}
}
@Override
public String getName(Object methodHandleInfo) {
try {
return (String) getName.invoke(methodHandleInfo);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandleInfo#getName", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandleInfo#getName", exception.getCause());
}
}
@Override
public Class returnType(Object methodType) {
try {
return (Class) returnType.invoke(methodType);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodType#returnType", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.reflect.MethodType#returnType", exception.getCause());
}
}
@Override
public List> parameterArray(Object methodType) {
try {
return Arrays.asList((Class[]) parameterArray.invoke(methodType));
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.reflect.MethodType#parameterArray", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.reflect.MethodType#parameterArray", exception.getCause());
}
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
AbstractBase that = (AbstractBase) other;
return publicLookup.equals(that.publicLookup)
&& getName.equals(that.getName)
&& getDeclaringClass.equals(that.getDeclaringClass)
&& getReferenceKind.equals(that.getReferenceKind)
&& getMethodType.equals(that.getMethodType)
&& returnType.equals(that.returnType)
&& parameterArray.equals(that.parameterArray);
}
@Override
public int hashCode() {
int result = publicLookup.hashCode();
result = 31 * result + getName.hashCode();
result = 31 * result + getDeclaringClass.hashCode();
result = 31 * result + getReferenceKind.hashCode();
result = 31 * result + getMethodType.hashCode();
result = 31 * result + returnType.hashCode();
result = 31 * result + parameterArray.hashCode();
return result;
}
}
/**
* A dispatcher for introspecting a {@code java.lang.invoke.MethodHandle} instance on a virtual machine that officially supports this
* introspection, i.e. Java versions 8+.
*/
class ForModernVm extends AbstractBase {
/**
* A reference to the {@code java.lang.invoke.MethodHandles.Lookup#revealDirect} method.
*/
private final Method revealDirect;
/**
* Creates a dispatcher for a modern VM.
*
* @param publicLookup A reference to {@code java.lang.invoke.MethodHandles#publicLookup}.
* @param getName A reference to {@code java.lang.invoke.MethodHandleInfo#getName}.
* @param getDeclaringClass A reference to {@code java.lang.invoke.MethodHandleInfo#getDeclaringClass}.
* @param getReferenceKind A reference to {@code java.lang.invoke.MethodHandleInfo#getReferenceKind}.
* @param getMethodType A reference to {@code java.lang.invoke.MethodHandleInfo#getMethodType}.
* @param returnType A reference to {@code java.lang.invoke.MethodType#returnType}.
* @param parameterArray A reference to {@code java.lang.invoke.MethodType#parameterArray}.
* @param revealDirect A reference to the {@code java.lang.invoke.MethodHandles.Lookup#revealDirect} method.
*/
protected ForModernVm(Method publicLookup,
Method getName,
Method getDeclaringClass,
Method getReferenceKind,
Method getMethodType,
Method returnType,
Method parameterArray,
Method revealDirect) {
super(publicLookup, getName, getDeclaringClass, getReferenceKind, getMethodType, returnType, parameterArray);
this.revealDirect = revealDirect;
}
@Override
public Object reveal(Object lookup, Object methodHandle) {
try {
return revealDirect.invoke(lookup, methodHandle);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodHandles.Lookup#revealDirect", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodHandles.Lookup#revealDirect", exception.getCause());
}
}
@Override
public Dispatcher initialize(AccessControlContext accessControlContext) {
return this;
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
if (!super.equals(other)) return false;
ForModernVm that = (ForModernVm) other;
return revealDirect.equals(that.revealDirect);
}
@Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + revealDirect.hashCode();
return result;
}
@Override
public String toString() {
return "JavaInstance.MethodHandle.Dispatcher.ForModernVm{" +
"publicLookup=" + publicLookup +
", getName=" + getName +
", getDeclaringClass=" + getDeclaringClass +
", getReferenceKind=" + getReferenceKind +
", getMethodType=" + getMethodType +
", returnType=" + returnType +
", parameterArray=" + parameterArray +
", revealDirect=" + revealDirect +
'}';
}
}
/**
* A dispatcher that extracts the information of a method handle by using private APIs that are available in Java 7+.
*/
class ForIntermediateVm extends AbstractBase implements PrivilegedAction {
/**
* A reference to the {@code java.lang.invoke.MethodInfo} constructor.
*/
private final Constructor methodInfo;
/**
* Creates a dispatcher for an intermediate VM.
*
* @param publicLookup A reference to {@code java.lang.invoke.MethodHandles#publicLookup}.
* @param getName A reference to {@code java.lang.invoke.MethodHandleInfo#getName}.
* @param getDeclaringClass A reference to {@code java.lang.invoke.MethodHandleInfo#getDeclaringClass}.
* @param getReferenceKind A reference to {@code java.lang.invoke.MethodHandleInfo#getReferenceKind}.
* @param getMethodType A reference to {@code java.lang.invoke.MethodHandleInfo#getMethodType}.
* @param returnType A reference to {@code java.lang.invoke.MethodType#returnType}.
* @param parameterArray A reference to {@code java.lang.invoke.MethodType#parameterArray}.
* @param methodInfo A reference to the {@code java.lang.invoke.MethodInfo} constructor.
*/
protected ForIntermediateVm(Method publicLookup,
Method getName,
Method getDeclaringClass,
Method getReferenceKind,
Method getMethodType,
Method returnType,
Method parameterArray,
Constructor methodInfo) {
super(publicLookup, getName, getDeclaringClass, getReferenceKind, getMethodType, returnType, parameterArray);
this.methodInfo = methodInfo;
}
@Override
public Dispatcher initialize(AccessControlContext accessControlContext) {
return AccessController.doPrivileged(this, accessControlContext);
}
@Override
public Dispatcher run() {
// This is safe even in a multi-threaded environment as all threads set the instances accessible before invoking any methods.
// By always setting accessability, the security manager is always triggered if this operation was illegal.
methodInfo.setAccessible(true);
getName.setAccessible(true);
getDeclaringClass.setAccessible(true);
getReferenceKind.setAccessible(true);
getMethodType.setAccessible(true);
return this;
}
@Override
public Object reveal(Object lookup, Object methodHandle) {
try {
return methodInfo.newInstance(methodHandle);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Cannot access java.lang.invoke.MethodInfo()", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.invoke.MethodInfo()", exception.getCause());
} catch (InstantiationException exception) {
throw new IllegalStateException("Error constructing java.lang.invoke.MethodInfo", exception);
}
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
if (!super.equals(other)) return false;
ForIntermediateVm that = (ForIntermediateVm) other;
return methodInfo.equals(that.methodInfo);
}
@Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + methodInfo.hashCode();
return result;
}
@Override
public String toString() {
return "JavaInstance.MethodHandle.Dispatcher.ForIntermediateVm{" +
"publicLookup=" + publicLookup +
", getName=" + getName +
", getDeclaringClass=" + getDeclaringClass +
", getReferenceKind=" + getReferenceKind +
", getMethodType=" + getMethodType +
", returnType=" + returnType +
", parameterArray=" + parameterArray +
", methodInfo=" + methodInfo +
'}';
}
}
/**
* A dispatcher that does not support method handles at all.
*/
enum ForLegacyVm implements Initializable {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public Dispatcher initialize(AccessControlContext accessControlContext) {
throw new IllegalStateException("Unsupported type on current JVM: java.lang.invoke.MethodHandle");
}
@Override
public Object publicLookup() {
throw new IllegalStateException("Unsupported type on current JVM: java.lang.invoke.MethodHandle");
}
@Override
public String toString() {
return "JavaInstance.MethodHandle.Dispatcher.ForLegacyVm." + name();
}
}
}
/**
* A representation of a method handle's type.
*/
public enum HandleType {
/**
* A handle representing an invokevirtual invocation.
*/
INVOKE_VIRTUAL(Opcodes.H_INVOKEVIRTUAL),
/**
* A handle representing an invokestatic invocation.
*/
INVOKE_STATIC(Opcodes.H_INVOKESTATIC),
/**
* A handle representing an invokespecial invocation for a non-constructor.
*/
INVOKE_SPECIAL(Opcodes.H_INVOKESPECIAL),
/**
* A handle representing an invokeinterface invocation.
*/
INVOKE_INTERFACE(Opcodes.H_INVOKEINTERFACE),
/**
* A handle representing an invokespecial invocation for a constructor.
*/
INVOKE_SPECIAL_CONSTRUCTOR(Opcodes.H_NEWINVOKESPECIAL),
/**
* A handle representing a write of a non-static field invocation.
*/
PUT_FIELD(Opcodes.H_PUTFIELD),
/**
* A handle representing a read of a non-static field invocation.
*/
GET_FIELD(Opcodes.H_GETFIELD),
/**
* A handle representing a write of a static field invocation.
*/
PUT_STATIC_FIELD(Opcodes.H_PUTSTATIC),
/**
* A handle representing a read of a static field invocation.
*/
GET_STATIC_FIELD(Opcodes.H_GETSTATIC);
/**
* The represented identifier.
*/
private final int identifier;
/**
* Creates a new handle type.
*
* @param identifier The represented identifier.
*/
HandleType(int identifier) {
this.identifier = identifier;
}
/**
* Extracts a handle type for invoking the given method.
*
* @param methodDescription The method for which a handle type should be found.
* @return The handle type for the given method.
*/
protected static HandleType of(MethodDescription methodDescription) {
if (methodDescription.isStatic()) {
return INVOKE_STATIC;
} else if (methodDescription.isPrivate()) {
return INVOKE_SPECIAL;
} else if (methodDescription.isConstructor()) {
return INVOKE_SPECIAL_CONSTRUCTOR;
} else if (methodDescription.getDeclaringType().asErasure().isInterface()) {
return INVOKE_INTERFACE;
} else {
return INVOKE_VIRTUAL;
}
}
/**
* Extracts a handle type for the given identifier.
*
* @param identifier The identifier to extract a handle type for.
* @return The representing handle type.
*/
protected static HandleType of(int identifier) {
for (HandleType handleType : HandleType.values()) {
if (handleType.getIdentifier() == identifier) {
return handleType;
}
}
throw new IllegalArgumentException("Unknown handle type: " + identifier);
}
/**
* Extracts a handle type for invoking the given method via invokespecial.
*
* @param methodDescription The method for which a handle type should be found.
* @return The handle type for the given method.
*/
protected static HandleType ofSpecial(MethodDescription methodDescription) {
if (methodDescription.isStatic() || methodDescription.isAbstract()) {
throw new IllegalArgumentException("Cannot invoke " + methodDescription + " via invokespecial");
}
return methodDescription.isConstructor()
? INVOKE_SPECIAL_CONSTRUCTOR
: INVOKE_SPECIAL;
}
/**
* Extracts a handle type for a getter of the given field.
*
* @param fieldDescription The field for which to create a getter handle.
* @return The corresponding handle type.
*/
protected static HandleType ofGetter(FieldDescription fieldDescription) {
return fieldDescription.isStatic()
? GET_STATIC_FIELD
: GET_FIELD;
}
/**
* Extracts a handle type for a setter of the given field.
*
* @param fieldDescription The field for which to create a setter handle.
* @return The corresponding handle type.
*/
protected static HandleType ofSetter(FieldDescription fieldDescription) {
return fieldDescription.isStatic()
? PUT_STATIC_FIELD
: PUT_FIELD;
}
/**
* Returns the represented identifier.
*
* @return The represented identifier.
*/
public int getIdentifier() {
return identifier;
}
@Override
public String toString() {
return "JavaInstance.MethodHandle.HandleType." + name();
}
}
}
}