net.bytebuddy.implementation.bind.annotation.BindingPriority 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.type.TypeDescription;
import net.bytebuddy.implementation.bind.MethodDelegationBinder;
import net.bytebuddy.utility.nullability.MaybeNull;
import java.lang.annotation.*;
import static net.bytebuddy.matcher.ElementMatchers.named;
/**
* Defines a binding priority for a target method. If two target methods can be bound to a source method,
* the one with the higher priority will be selected.
*
* @see net.bytebuddy.implementation.MethodDelegation
* @see net.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface BindingPriority {
/**
* The default priority for methods not carrying the
* {@link net.bytebuddy.implementation.bind.annotation.BindingPriority}
* annotation.
*/
int DEFAULT = 1;
/**
* The binding priority for the annotated method. A method of higher priority will be preferred over a method
* of lower priority.
*
* @return The priority for the annotated method.
*/
int value();
/**
* An ambiguity resolver that considers the priority of a method as defined by the
* {@link net.bytebuddy.implementation.bind.annotation.BindingPriority}
* annotation.
*/
enum Resolver implements MethodDelegationBinder.AmbiguityResolver {
/**
* The singleton instance.
*/
INSTANCE;
/**
* A description of the {@link BindingPriority#value()} method.
*/
private static final MethodDescription.InDefinedShape VALUE = TypeDescription.ForLoadedType.of(BindingPriority.class)
.getDeclaredMethods()
.filter(named("value"))
.getOnly();
/**
* Resolves the explicitly stated binding priority of a method or returns the default value if no such
* explicit information can be found.
*
* @param bindingPriority The annotation of the method or {@code null} if no such annotation was found.
* @return The factual priority of the method under investigation.
*/
private static int resolve(@MaybeNull AnnotationDescription.Loadable bindingPriority) {
return bindingPriority == null
? BindingPriority.DEFAULT
: bindingPriority.getValue(VALUE).resolve(Integer.class);
}
/**
* {@inheritDoc}
*/
public Resolution resolve(MethodDescription source,
MethodDelegationBinder.MethodBinding left,
MethodDelegationBinder.MethodBinding right) {
int leftPriority = resolve(left.getTarget().getDeclaredAnnotations().ofType(BindingPriority.class));
int rightPriority = resolve(right.getTarget().getDeclaredAnnotations().ofType(BindingPriority.class));
if (leftPriority == rightPriority) {
return Resolution.AMBIGUOUS;
} else if (leftPriority < rightPriority) {
return Resolution.RIGHT;
} else {
return Resolution.LEFT;
}
}
}
}