net.bytebuddy.implementation.bind.annotation.SuperMethodHandle 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.assign.Assigner;
import net.bytebuddy.implementation.bytecode.constant.NullConstant;
import net.bytebuddy.utility.JavaType;
import java.lang.annotation.*;
import static net.bytebuddy.matcher.ElementMatchers.named;
/**
* A parameter with this annotation is assigned an instance of {@code java.lang.invoke.MethodHandle} which invokes the super
* implementation of this method. If such a method is not available, this annotation causes that this delegation target cannot
* be bound unless {@link SuperMethodHandle#nullIfImpossible()} is set to {@code true}.
*
* @see net.bytebuddy.implementation.MethodDelegation
* @see TargetMethodAnnotationDrivenBinder
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.PARAMETER)
public @interface SuperMethodHandle {
/**
* Indicates that the assigned method should attempt the invocation of an unambiguous default method if no super method is available.
*
* @return {@code true} if a default method should be invoked if it is not ambiguous and no super class method is available.
*/
boolean fallbackToDefault() default true;
/**
* Indicates that {@code null} should be assigned to this parameter if no super method is invokable.
*
* @return {@code true} if {@code null} should be assigned if no valid method can be assigned.
*/
boolean nullIfImpossible() default false;
/**
* A binder for the {@link SuperMethodHandle} annotation.
*/
enum Binder implements TargetMethodAnnotationDrivenBinder.ParameterBinder {
/**
* The singleton instance.
*/
INSTANCE;
/**
* A description of the {@link SuperMethodHandle#fallbackToDefault()} method.
*/
private static final MethodDescription.InDefinedShape FALLBACK_TO_DEFAULT;
/**
* A description of the {@link SuperMethodHandle#nullIfImpossible()} method.
*/
private static final MethodDescription.InDefinedShape NULL_IF_IMPOSSIBLE;
/*
* Resolves annotation properties.
*/
static {
MethodList methods = TypeDescription.ForLoadedType.of(SuperMethodHandle.class).getDeclaredMethods();
FALLBACK_TO_DEFAULT = methods.filter(named("fallbackToDefault")).getOnly();
NULL_IF_IMPOSSIBLE = methods.filter(named("nullIfImpossible")).getOnly();
}
/**
* {@inheritDoc}
*/
public Class getHandledType() {
return SuperMethodHandle.class;
}
/**
* {@inheritDoc}
*/
public MethodDelegationBinder.ParameterBinding bind(AnnotationDescription.Loadable annotation,
MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner,
Assigner.Typing typing) {
if (!target.getType().asErasure().isAssignableFrom(JavaType.METHOD_HANDLE.getTypeStub())) {
throw new IllegalStateException("Cannot assign MethodHandle type to " + target);
} else if (source.isMethod()) {
Implementation.SpecialMethodInvocation specialMethodInvocation = (annotation.getValue(FALLBACK_TO_DEFAULT).resolve(Boolean.class)
? implementationTarget.invokeDominant(source.asSignatureToken())
: implementationTarget.invokeSuper(source.asSignatureToken())).withCheckedCompatibilityTo(source.asTypeToken());
if (specialMethodInvocation.isValid()) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(specialMethodInvocation.toMethodHandle().toStackManipulation());
} else if (annotation.getValue(NULL_IF_IMPOSSIBLE).resolve(Boolean.class)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(NullConstant.INSTANCE);
} else {
return MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
}
} else if (annotation.getValue(NULL_IF_IMPOSSIBLE).resolve(Boolean.class)) {
return new MethodDelegationBinder.ParameterBinding.Anonymous(NullConstant.INSTANCE);
} else {
return MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
}
}
}
}