net.bytebuddy.implementation.bind.annotation.This 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.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.NullConstant;
import net.bytebuddy.implementation.bytecode.member.MethodVariableAccess;
import java.lang.annotation.*;
import static net.bytebuddy.matcher.ElementMatchers.named;
/**
*
* Parameters that are annotated with this annotation will be assigned a reference to the instrumented object, if
* the instrumented method is not static. Otherwise, the method with this parameter annotation will be excluded from
* the list of possible binding candidates of the static source method.
*
*
* Important: Don't confuse this annotation with {@link net.bytebuddy.asm.Advice.This} or
* {@link net.bytebuddy.asm.MemberSubstitution.This}. 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 This {
/**
* Determines if the annotated parameter should be bound to {@code null} when intercepting a {@code static} method.
*
* @return {@code true} if the annotated parameter should be bound to {@code null} as a fallback.
*/
boolean optional() default false;
/**
* A binder for handling the
* {@link net.bytebuddy.implementation.bind.annotation.This}
* annotation.
*
* @see TargetMethodAnnotationDrivenBinder
*/
enum Binder implements TargetMethodAnnotationDrivenBinder.ParameterBinder {
/**
* The singleton instance.
*/
INSTANCE;
/**
* A description of the {@link Pipe#serializableProxy()} method.
*/
private static final MethodDescription.InDefinedShape OPTIONAL = TypeDescription.ForLoadedType.of(This.class)
.getDeclaredMethods()
.filter(named("optional"))
.getOnly();
/**
* {@inheritDoc}
*/
public Class getHandledType() {
return This.class;
}
/**
* {@inheritDoc}
*/
public MethodDelegationBinder.ParameterBinding bind(AnnotationDescription.Loadable annotation,
MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner,
Assigner.Typing typing) {
if (target.getType().isPrimitive()) {
throw new IllegalStateException(target + " uses a primitive type with a @This annotation");
} else if (target.getType().isArray()) {
throw new IllegalStateException(target + " uses an array type with a @This annotation");
} else if (source.isStatic() && !annotation.getValue(OPTIONAL).resolve(Boolean.class)) {
return MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
}
return new MethodDelegationBinder.ParameterBinding.Anonymous(source.isStatic()
? NullConstant.INSTANCE
: new StackManipulation.Compound(MethodVariableAccess.loadThis(),
assigner.assign(implementationTarget.getInstrumentedType().asGenericType(), target.getType(), typing)));
}
}
}