com.fitbur.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder Maven / Gradle / Ivy
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package com.fitbur.bytebuddy.implementation.bind.annotation;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import com.fitbur.bytebuddy.description.annotation.AnnotationDescription;
import com.fitbur.bytebuddy.description.method.MethodDescription;
import com.fitbur.bytebuddy.description.method.ParameterDescription;
import com.fitbur.bytebuddy.description.type.TypeDescription;
import com.fitbur.bytebuddy.implementation.Implementation;
import com.fitbur.bytebuddy.implementation.bind.MethodDelegationBinder;
import com.fitbur.bytebuddy.implementation.bytecode.Removal;
import com.fitbur.bytebuddy.implementation.bytecode.StackManipulation;
import com.fitbur.bytebuddy.implementation.bytecode.assign.Assigner;
import com.fitbur.bytebuddy.implementation.bytecode.member.MethodReturn;
import java.lang.annotation.Annotation;
import java.util.*;
/**
* This {@link com.fitbur.bytebuddy.implementation.bind.MethodDelegationBinder} binds
* method by analyzing annotations found on the target method that is subject to a method binding.
*/
public class TargetMethodAnnotationDrivenBinder implements MethodDelegationBinder {
/**
* The processor for performing an actual method delegation.
*/
private final DelegationProcessor delegationProcessor;
/**
* The provider for annotations to be supplied for binding of non-annotated parameters.
*/
private final DefaultsProvider defaultsProvider;
/**
* The termination handler to be applied.
*/
private final TerminationHandler terminationHandler;
/**
* An user-supplied assigner to use for variable assignments.
*/
private final Assigner assigner;
/**
* A delegate for actually invoking a method.
*/
private final MethodInvoker methodInvoker;
/**
* Creates a new method delegation binder that binds method based on annotations found on the target method.
*
* @param parameterBinders A list of parameter binder delegates. Each such delegate is responsible for creating a
* {@link com.fitbur.bytebuddy.implementation.bind.MethodDelegationBinder.ParameterBinding}
* for a specific annotation.
* @param defaultsProvider A provider that creates an annotation for parameters that are not annotated by any annotation
* that is handled by any of the registered {@code parameterBinders}.
* @param terminationHandler The termination handler to be applied.
* @param assigner An assigner that is supplied to the {@code parameterBinders} and that is used for binding the return value.
* @param methodInvoker A delegate for applying the actual method invocation of the target method.
*/
public TargetMethodAnnotationDrivenBinder(List> parameterBinders,
DefaultsProvider defaultsProvider,
TerminationHandler terminationHandler,
Assigner assigner,
MethodInvoker methodInvoker) {
delegationProcessor = DelegationProcessor.of(parameterBinders);
this.defaultsProvider = defaultsProvider;
this.terminationHandler = terminationHandler;
this.assigner = assigner;
this.methodInvoker = methodInvoker;
}
@Override
public MethodBinding bind(Implementation.Target implementationTarget,
MethodDescription source,
MethodDescription target) {
if (IgnoreForBinding.Verifier.check(target)) {
return MethodBinding.Illegal.INSTANCE;
}
StackManipulation methodTermination = terminationHandler.resolve(assigner, source, target);
if (!methodTermination.isValid()) {
return MethodBinding.Illegal.INSTANCE;
}
MethodBinding.Builder methodDelegationBindingBuilder = new MethodBinding.Builder(methodInvoker, target);
Iterator defaults = defaultsProvider.makeIterator(implementationTarget, source, target);
for (ParameterDescription parameterDescription : target.getParameters()) {
ParameterBinding parameterBinding = delegationProcessor
.handler(parameterDescription.getDeclaredAnnotations(), defaults)
.bind(source,
parameterDescription,
implementationTarget,
assigner);
if (!parameterBinding.isValid() || !methodDelegationBindingBuilder.append(parameterBinding)) {
return MethodBinding.Illegal.INSTANCE;
}
}
return methodDelegationBindingBuilder.build(methodTermination);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
TargetMethodAnnotationDrivenBinder that = (TargetMethodAnnotationDrivenBinder) other;
return assigner.equals(that.assigner)
&& defaultsProvider.equals(that.defaultsProvider)
&& terminationHandler.equals(that.terminationHandler)
&& delegationProcessor.equals(that.delegationProcessor)
&& methodInvoker.equals(that.methodInvoker);
}
@Override
public int hashCode() {
int result = delegationProcessor.hashCode();
result = 31 * result + defaultsProvider.hashCode();
result = 31 * result + terminationHandler.hashCode();
result = 31 * result + assigner.hashCode();
result = 31 * result + methodInvoker.hashCode();
return result;
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder{" +
"delegationProcessor=" + delegationProcessor +
", defaultsProvider=" + defaultsProvider +
", terminationHandler=" + terminationHandler +
", assigner=" + assigner +
", methodInvoker=" + methodInvoker +
'}';
}
/**
* A parameter binder is used as a delegate for binding a parameter according to a particular annotation type found
* on this parameter.
*
* @param The {@link java.lang.annotation.Annotation#annotationType()} handled by this parameter binder.
*/
@SuppressFBWarnings(value = "IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION", justification = "No circularity, initialization is safe")
public interface ParameterBinder {
/**
* The default parameter binders to be used.
*/
List> DEFAULTS = Collections.unmodifiableList(Arrays.>asList(
Argument.Binder.INSTANCE,
AllArguments.Binder.INSTANCE,
Origin.Binder.INSTANCE,
This.Binder.INSTANCE,
Super.Binder.INSTANCE,
Default.Binder.INSTANCE,
SuperCall.Binder.INSTANCE,
DefaultCall.Binder.INSTANCE,
FieldValue.Binder.INSTANCE,
StubValue.Binder.INSTANCE,
Empty.Binder.INSTANCE));
/**
* The annotation type that is handled by this parameter binder.
*
* @return The {@link java.lang.annotation.Annotation#annotationType()} handled by this parameter binder.
*/
Class getHandledType();
/**
* Creates a parameter binding for the given target parameter.
*
* @param annotation The annotation that was cause for the delegation to this argument binder.
* @param source The intercepted source method.
* @param target Tge target parameter that is subject to be bound to
* intercepting the {@code source} method.
* @param implementationTarget The target of the current implementation that is subject to this binding.
* @param assigner An assigner that can be used for applying the binding.
* @return A parameter binding for the requested target method parameter.
*/
ParameterBinding bind(AnnotationDescription.Loadable annotation,
MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner);
}
/**
* Implementations of the defaults provider interface create annotations for parameters that are not annotated with
* a known annotation.
*
* @see com.fitbur.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder
*/
public interface DefaultsProvider {
/**
* Creates an iterator from which a value is pulled each time no processable annotation is found on a
* method parameter.
*
* @param implementationTarget The target of the current implementation.
* @param source The source method that is bound to the {@code target} method.
* @param target Tge target method that is subject to be bound by the {@code source} method.
* @return An iterator that supplies default annotations for
*/
Iterator makeIterator(Implementation.Target implementationTarget,
MethodDescription source,
MethodDescription target);
/**
* A defaults provider that does not supply any defaults. If this defaults provider is used, a target
* method is required to annotate each parameter with a known annotation.
*/
enum Empty implements DefaultsProvider {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public Iterator makeIterator(Implementation.Target implementationTarget,
MethodDescription source,
MethodDescription target) {
return EmptyIterator.INSTANCE;
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.DefaultsProvider.Empty." + name();
}
/**
* A trivial iterator without any elements.
*/
protected enum EmptyIterator implements Iterator {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public boolean hasNext() {
return false;
}
@Override
public AnnotationDescription next() {
throw new NoSuchElementException();
}
@Override
public void remove() {
throw new NoSuchElementException();
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.DefaultsProvider.Empty.EmptyIterator." + name();
}
}
}
}
/**
* Responsible for creating a {@link StackManipulation}
* that is applied after the interception method is applied.
*/
public interface TerminationHandler {
/**
* Creates a stack manipulation that is to be applied after the method return.
*
* @param assigner The supplied assigner.
* @param source The source method that is bound to the {@code target} method.
* @param target The target method that is subject to be bound by the {@code source} method.
* @return A stack manipulation that is applied after the method return.
*/
StackManipulation resolve(Assigner assigner, MethodDescription source, MethodDescription target);
/**
* A termination handler that returns the return value of the interception method.
*/
enum Returning implements TerminationHandler {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public StackManipulation resolve(Assigner assigner, MethodDescription source, MethodDescription target) {
return new StackManipulation.Compound(assigner.assign(target.isConstructor()
? target.getDeclaringType().asGenericType()
: target.getReturnType(),
source.getReturnType(),
RuntimeType.Verifier.check(target)), MethodReturn.returning(source.getReturnType().asErasure()));
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.TerminationHandler.Returning." + name();
}
}
/**
* A termination handler that pops the return value of the interception method.
*/
enum Dropping implements TerminationHandler {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public StackManipulation resolve(Assigner assigner, MethodDescription source, MethodDescription target) {
return Removal.pop(target.isConstructor()
? target.getDeclaringType().asErasure()
: target.getReturnType().asErasure());
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.TerminationHandler.Dropping." + name();
}
}
}
/**
* A delegation processor is a helper class for a
* {@link com.fitbur.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder}
* for performing its actual logic. By outsourcing this logic to this helper class, a cleaner implementation
* can be provided.
*/
protected static class DelegationProcessor {
/**
* A map of registered annotation types to the binder that is responsible for binding a parameter
* that is annotated with the given annotation.
*/
private final Map> parameterBinders;
/**
* Creates a new delegation processor.
*
* @param parameterBinders A mapping of parameter binders by their handling type.
*/
protected DelegationProcessor(Map> parameterBinders) {
this.parameterBinders = parameterBinders;
}
/**
* Creates a new delegation processor.
*
* @param parameterBinders A list of parameter binder delegates. Each such delegate is responsible for creating
* a {@link com.fitbur.bytebuddy.implementation.bind.MethodDelegationBinder.ParameterBinding}
* for a specific annotation.
* @return A corresponding delegation processor.
*/
protected static DelegationProcessor of(List> parameterBinders) {
Map> parameterBinderMap = new HashMap>();
for (ParameterBinder parameterBinder : parameterBinders) {
if (parameterBinderMap.put(new TypeDescription.ForLoadedType(parameterBinder.getHandledType()), parameterBinder) != null) {
throw new IllegalArgumentException("Attempt to bind two handlers to " + parameterBinder.getHandledType());
}
}
return new DelegationProcessor(parameterBinderMap);
}
/**
* Locates a handler which is responsible for processing the given parameter. If no explicit handler can
* be located, a fallback handler is provided.
*
* @param annotations The annotations of the parameter for which a handler should be provided.
* @param defaults The defaults provider to be queried if no explicit handler mapping could be found.
* @return A handler for processing the parameter with the given annotations.
*/
private Handler handler(List annotations, Iterator defaults) {
Handler handler = null;
for (AnnotationDescription annotation : annotations) {
ParameterBinder parameterBinder = parameterBinders.get(annotation.getAnnotationType());
if (parameterBinder != null && handler != null) {
throw new IllegalStateException("Ambiguous binding for parameter annotated with two handled annotation types");
} else if (parameterBinder != null /* && handler == null */) {
handler = makeHandler(parameterBinder, annotation);
}
}
if (handler == null) { // No handler was found: attempt using defaults provider.
if (defaults.hasNext()) {
AnnotationDescription defaultAnnotation = defaults.next();
ParameterBinder parameterBinder = parameterBinders.get(defaultAnnotation.getAnnotationType());
if (parameterBinder == null) {
return Handler.Unbound.INSTANCE;
} else {
handler = makeHandler(parameterBinder, defaultAnnotation);
}
} else {
return Handler.Unbound.INSTANCE;
}
}
return handler;
}
/**
* Creates a handler for a given annotation.
*
* @param parameterBinder The parameter binder that should process an annotation.
* @param annotation An annotation instance that can be understood by this parameter binder.
* @return A handler for processing the given annotation.
*/
@SuppressWarnings("unchecked")
private Handler makeHandler(ParameterBinder parameterBinder, AnnotationDescription annotation) {
return new Handler.Bound((ParameterBinder) parameterBinder,
(AnnotationDescription.Loadable) annotation.prepare(parameterBinder.getHandledType()));
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& parameterBinders.equals(((DelegationProcessor) other).parameterBinders);
}
@Override
public int hashCode() {
return parameterBinders.hashCode();
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.DelegationProcessor{" +
"parameterBinders=" + parameterBinders +
'}';
}
/**
* A handler is responsible for processing a parameter's binding.
*/
protected interface Handler {
/**
* Handles a parameter binding.
*
* @param source The intercepted source method.
* @param target The target parameter that is subject to binding.
* @param implementationTarget The target of the current implementation.
* @param assigner An assigner that can be used for applying the binding.
* @return A parameter binding that reflects the given arguments.
*/
ParameterBinding bind(MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner);
/**
* An unbound handler is a fallback for returning an illegal binding for parameters for which no parameter
* binder could be located.
*/
enum Unbound implements Handler {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public ParameterBinding bind(MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner) {
return ParameterBinding.Illegal.INSTANCE;
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.DelegationProcessor.Handler.Unbound." + name();
}
}
/**
* A bound handler represents an unambiguous parameter binder that was located for a given array of
* annotations.
*
* @param The annotation type of a given handler.
*/
class Bound implements Handler {
/**
* The parameter binder that is actually responsible for binding the parameter.
*/
private final ParameterBinder parameterBinder;
/**
* The annotation value that lead to the binding of this handler.
*/
private final AnnotationDescription.Loadable annotation;
/**
* Creates a new bound handler.
*
* @param parameterBinder The parameter binder that is actually responsible for binding the parameter.
* @param annotation The annotation value that lead to the binding of this handler.
*/
public Bound(ParameterBinder parameterBinder, AnnotationDescription.Loadable annotation) {
this.parameterBinder = parameterBinder;
this.annotation = annotation;
}
@Override
public ParameterBinding bind(MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner) {
return parameterBinder.bind(annotation,
source,
target,
implementationTarget,
assigner);
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& parameterBinder.equals(((Bound) other).parameterBinder)
&& annotation.equals(((Bound) other).annotation);
}
@Override
public int hashCode() {
int result = parameterBinder.hashCode();
result = 31 * result + annotation.hashCode();
return result;
}
@Override
public String toString() {
return "TargetMethodAnnotationDrivenBinder.DelegationProcessor.Handler.Bound{" +
"parameterBinder=" + parameterBinder +
", annotation=" + annotation +
'}';
}
}
}
}
}
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