net.bytebuddy.implementation.bind.annotation.Origin Maven / Gradle / Ivy
/*
* Copyright 2014 - Present Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.bytebuddy.implementation.bind.annotation;
import net.bytebuddy.description.annotation.AnnotationDescription;
import net.bytebuddy.description.method.MethodDescription;
import net.bytebuddy.description.method.MethodList;
import net.bytebuddy.description.method.ParameterDescription;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.implementation.Implementation;
import net.bytebuddy.implementation.bind.MethodDelegationBinder;
import net.bytebuddy.implementation.bytecode.StackManipulation;
import net.bytebuddy.implementation.bytecode.assign.Assigner;
import net.bytebuddy.implementation.bytecode.constant.*;
import net.bytebuddy.implementation.bytecode.member.MethodInvocation;
import net.bytebuddy.utility.JavaConstant;
import net.bytebuddy.utility.JavaType;
import java.lang.annotation.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import static net.bytebuddy.matcher.ElementMatchers.named;
/**
*
* The origin annotation provides some meta information about the source method that is bound to this method where
* the binding is dependant of the parameter's type:
*
*
* - If the annotated parameter is of type {@link java.lang.reflect.Method}, {@link java.lang.reflect.Constructor} or
* {@code java.lang.reflect.Executable}, the parameter is assigned a reference to the method or constructor it
* instruments. If the reference is not assignable to the sort of the intercepted source, the target is not considered
* for binding.
* - If the annotated parameter is of type {@link java.lang.Class}, the parameter is assigned a reference of the
* type of the instrumented type.
* - If the annotated parameter is of type {@link java.lang.String}, the parameter is assigned a string with
* the value that would be returned by the {@link Method#toString()} method.
*
* - If the annotated parameter is a {@code int} type, it is assigned the intercepted method's modifiers.
* - If the annotated type is {@code java.lang.invoke.MethodHandle}, a handle of the intercepted method is injected.
* A {@code java.lang.invoke.MethodHandle} is stored in a class's constant pool and does therefore not face the same
* runtime performance limitations as a (non-cached) {@link java.lang.reflect.Method} reference. Method handles are
* only supported for byte code versions starting from Java 7.
* - If the annotated type is {@code java.lang.invoke.MethodType}, a description of the intercepted method's type
* is injected. Method type descriptions are only supported for byte code versions starting from Java 7.
* - If the annotated type is {@code java.lang.invoke.MethodHandles$Lookup}, a method handle lookup of the instrumented
* class is returned. Method type descriptions are only supported for byte code versions starting from Java 7.
*
*
* Any other parameter type will cause an {@link java.lang.IllegalStateException}.
*
*
* Important: A method handle or method type reference can only be used if the referenced method's types are all visible
* to the instrumented type or an {@link IllegalAccessError} will be thrown at runtime.
*
*
* Important: Don't confuse this annotation with {@link net.bytebuddy.asm.Advice.Origin} or
* {@link net.bytebuddy.asm.MemberSubstitution.Origin}. This annotation should be used with
* {@link net.bytebuddy.implementation.MethodDelegation} only.
*
*
* @see net.bytebuddy.implementation.MethodDelegation
* @see net.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.PARAMETER)
public @interface Origin {
/**
* Determines if the value that is assigned by this annotation is cached. For values that can be stored in the constant pool,
* this value is ignored as such values are cached implicitly. As a result, this value currently only affects caching of
* {@link Method} instances.
*
* @return {@code true} if the value for this parameter should be cached in a {@code static} field inside the instrumented class.
*/
boolean cache() default true;
/**
* Determines if the method should be resolved by using an {@code java.security.AccessController} using the privileges of the generated class.
* Doing so requires the generation of an auxiliary class that implements {@code java.security.PrivilegedExceptionAction}.
*
* @return {@code true} if the class should be looked up using an {@code java.security.AccessController}.
*/
boolean privileged() default false;
/**
* A binder for binding parameters that are annotated with {@link net.bytebuddy.implementation.bind.annotation.Origin}.
*
* @see TargetMethodAnnotationDrivenBinder
*/
enum Binder implements TargetMethodAnnotationDrivenBinder.ParameterBinder {
/**
* The singleton instance.
*/
INSTANCE;
/**
* A description of the {@link Origin#cache()} method.
*/
private static final MethodDescription.InDefinedShape CACHE;
/**
* A description of the {@link Origin#privileged()} method.
*/
private static final MethodDescription.InDefinedShape PRIVILEGED;
/*
* Resolves annotation properties.
*/
static {
MethodList methods = TypeDescription.ForLoadedType.of(Origin.class).getDeclaredMethods();
CACHE = methods.filter(named("cache")).getOnly();
PRIVILEGED = methods.filter(named("privileged")).getOnly();
}
/**
* Loads a method constant onto the operand stack.
*
* @param annotation The origin annotation.
* @param methodDescription The method description to load.
* @return An appropriate stack manipulation.
*/
private static StackManipulation methodConstant(AnnotationDescription.Loadable annotation, MethodDescription.InDefinedShape methodDescription) {
MethodConstant.CanCache methodConstant = annotation.getValue(PRIVILEGED).resolve(Boolean.class)
? MethodConstant.ofPrivileged(methodDescription)
: MethodConstant.of(methodDescription);
return annotation.getValue(CACHE).resolve(Boolean.class)
? methodConstant.cached()
: methodConstant;
}
/**
* {@inheritDoc}
*/
public Class getHandledType() {
return Origin.class;
}
/**
* {@inheritDoc}
*/
public MethodDelegationBinder.ParameterBinding bind(AnnotationDescription.Loadable annotation,
MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner,
Assigner.Typing typing) {
TypeDescription parameterType = target.getType().asErasure();
if (parameterType.represents(Class.class)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(ClassConstant.of(implementationTarget.getOriginType().asErasure()));
} else if (parameterType.represents(Method.class)) {
return source.isMethod()
? new MethodDelegationBinder.ParameterBinding.Anonymous(methodConstant(annotation, source.asDefined()))
: MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
} else if (parameterType.represents(Constructor.class)) {
return source.isConstructor()
? new MethodDelegationBinder.ParameterBinding.Anonymous(methodConstant(annotation, source.asDefined()))
: MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
} else if (JavaType.EXECUTABLE.getTypeStub().equals(parameterType)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(methodConstant(annotation, source.asDefined()));
} else if (parameterType.represents(String.class)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(new TextConstant(source.toString()));
} else if (parameterType.represents(int.class)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(IntegerConstant.forValue(source.getModifiers()));
} else if (parameterType.equals(JavaType.METHOD_HANDLE.getTypeStub())) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(JavaConstant.MethodHandle.of(source.asDefined()).toStackManipulation());
} else if (parameterType.equals(JavaType.METHOD_TYPE.getTypeStub())) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(JavaConstant.MethodType.of(source.asDefined()).toStackManipulation());
} else if (parameterType.equals(JavaType.METHOD_HANDLES_LOOKUP.getTypeStub())) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(MethodInvocation.lookup());
} else {
throw new IllegalStateException("The " + target + " method's " + target.getIndex() +
" parameter is annotated with a Origin annotation with an argument not representing a Class," +
" Method, Constructor, String, int, MethodType or MethodHandle type");
}
}
}
}