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package com.fitbur.bytebuddy.implementation.bind.annotation;
import com.fitbur.bytebuddy.ByteBuddy;
import com.fitbur.bytebuddy.ClassFileVersion;
import com.fitbur.bytebuddy.description.annotation.AnnotationDescription;
import com.fitbur.bytebuddy.description.field.FieldDescription;
import com.fitbur.bytebuddy.description.field.FieldList;
import com.fitbur.bytebuddy.description.method.MethodDescription;
import com.fitbur.bytebuddy.description.method.MethodList;
import com.fitbur.bytebuddy.description.method.ParameterDescription;
import com.fitbur.bytebuddy.description.type.TypeDefinition;
import com.fitbur.bytebuddy.description.type.TypeDescription;
import com.fitbur.bytebuddy.dynamic.DynamicType;
import com.fitbur.bytebuddy.dynamic.TargetType;
import com.fitbur.bytebuddy.dynamic.scaffold.InstrumentedType;
import com.fitbur.bytebuddy.dynamic.scaffold.subclass.ConstructorStrategy;
import com.fitbur.bytebuddy.implementation.Implementation;
import com.fitbur.bytebuddy.implementation.auxiliary.AuxiliaryType;
import com.fitbur.bytebuddy.implementation.bind.MethodDelegationBinder;
import com.fitbur.bytebuddy.implementation.bytecode.ByteCodeAppender;
import com.fitbur.bytebuddy.implementation.bytecode.Duplication;
import com.fitbur.bytebuddy.implementation.bytecode.StackManipulation;
import com.fitbur.bytebuddy.implementation.bytecode.TypeCreation;
import com.fitbur.bytebuddy.implementation.bytecode.assign.Assigner;
import com.fitbur.bytebuddy.implementation.bytecode.member.FieldAccess;
import com.fitbur.bytebuddy.implementation.bytecode.member.MethodInvocation;
import com.fitbur.bytebuddy.implementation.bytecode.member.MethodReturn;
import com.fitbur.bytebuddy.implementation.bytecode.member.MethodVariableAccess;
import com.fitbur.bytebuddy.jar.asm.MethodVisitor;
import com.fitbur.bytebuddy.jar.asm.Opcodes;
import java.io.Serializable;
import java.lang.annotation.*;
import java.util.Collections;
import static com.fitbur.bytebuddy.matcher.ElementMatchers.*;
/**
* Using this annotation it is possible to access fields by getter and setter types. Before this annotation can be
* used, it needs to be installed with two types. The getter type must be defined in a single-method interface
* with a single method that returns an {@link java.lang.Object} type and takes no arguments. The getter interface
* must similarly return {@code void} and take a single {@link java.lang.Object} argument. After installing these
* interfaces with the {@link FieldProxy.Binder}, this
* binder needs to be registered with a {@link com.fitbur.bytebuddy.implementation.MethodDelegation} before it can be used.
*
* @see com.fitbur.bytebuddy.implementation.MethodDelegation
* @see com.fitbur.bytebuddy.implementation.bind.annotation.TargetMethodAnnotationDrivenBinder
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.PARAMETER)
public @interface FieldProxy {
/**
* A placeholder name to indicate that a field name should be inferred by the name of the intercepted
* method by the Java bean naming conventions.
*/
String BEAN_PROPERTY = "";
/**
* Determines if the proxy should be serializable.
*
* @return {@code true} if the proxy should be serializable.
*/
boolean serializableProxy() default false;
/**
* Determines the name of the field that is to be accessed. If this property is not set, a field name is inferred
* by the intercepted method after the Java beans naming conventions.
*
* @return The name of the field to be accessed.
*/
String value() default "";
/**
* Determines which type defines the field that is to be accessed. If this property is not set, the most field
* that is defined highest in the type hierarchy is accessed.
*
* @return The type that defines the accessed field.
*/
Class definingType() default void.class;
/**
* A binder for the {@link FieldProxy} annotation.
*/
class Binder implements TargetMethodAnnotationDrivenBinder.ParameterBinder {
/**
* A reference to the method that declares the field annotation's defining type property.
*/
private static final MethodDescription.InDefinedShape DEFINING_TYPE;
/**
* A reference to the method that declares the field annotation's field name property.
*/
private static final MethodDescription.InDefinedShape FIELD_NAME;
/**
* A reference to the method that declares the field annotation's serializable proxy property.
*/
private static final MethodDescription.InDefinedShape SERIALIZABLE_PROXY;
/*
* Fetches a reference to all annotation properties.
*/
static {
MethodList methodList = new TypeDescription.ForLoadedType(FieldProxy.class).getDeclaredMethods();
DEFINING_TYPE = methodList.filter(named("definingType")).getOnly();
FIELD_NAME = methodList.filter(named("value")).getOnly();
SERIALIZABLE_PROXY = methodList.filter(named("serializableProxy")).getOnly();
}
/**
* The getter method to be implemented by a getter proxy.
*/
private final MethodDescription getterMethod;
/**
* The setter method to be implemented by a setter proxy.
*/
private final MethodDescription setterMethod;
/**
* Creates a new binder for the {@link FieldProxy}
* annotation.
*
* @param getterMethod The getter method to be implemented by a getter proxy.
* @param setterMethod The setter method to be implemented by a setter proxy.
*/
protected Binder(MethodDescription getterMethod, MethodDescription setterMethod) {
this.getterMethod = getterMethod;
this.setterMethod = setterMethod;
}
/**
* Creates a binder by installing two proxy types which are implemented by this binder if a field getter
* or a field setter is requested by using the
* {@link FieldProxy} annotation.
*
* @param getterType The type which should be used for getter proxies. The type must
* represent an interface which defines a single method which returns an
* {@link java.lang.Object} return type and does not take any arguments. The use of generics
* is permitted.
* @param setterType The type which should be uses for setter proxies. The type must
* represent an interface which defines a single method which returns {@code void}
* and takes a single {@link java.lang.Object}-typed argument. The use of generics
* is permitted.
* @return A binder for the {@link FieldProxy}
* annotation.
*/
public static TargetMethodAnnotationDrivenBinder.ParameterBinder install(Class getterType, Class setterType) {
return install(new TypeDescription.ForLoadedType(getterType), new TypeDescription.ForLoadedType(setterType));
}
/**
* Creates a binder by installing two proxy types which are implemented by this binder if a field getter
* or a field setter is requested by using the
* {@link FieldProxy} annotation.
*
* @param getterType The type which should be used for getter proxies. The type must
* represent an interface which defines a single method which returns an
* {@link java.lang.Object} return type and does not take any arguments. The use of generics
* is permitted.
* @param setterType The type which should be uses for setter proxies. The type must
* represent an interface which defines a single method which returns {@code void}
* and takes a single {@link java.lang.Object}-typed argument. The use of generics
* is permitted.
* @return A binder for the {@link FieldProxy}
* annotation.
*/
public static TargetMethodAnnotationDrivenBinder.ParameterBinder install(TypeDescription getterType, TypeDescription setterType) {
MethodDescription getterMethod = onlyMethod(getterType);
if (!getterMethod.getReturnType().asErasure().represents(Object.class)) {
throw new IllegalArgumentException(getterMethod + " must take a single Object-typed parameter");
} else if (getterMethod.getParameters().size() != 0) {
throw new IllegalArgumentException(getterMethod + " must not declare parameters");
}
MethodDescription setterMethod = onlyMethod(setterType);
if (!setterMethod.getReturnType().asErasure().represents(void.class)) {
throw new IllegalArgumentException(setterMethod + " must return void");
} else if (setterMethod.getParameters().size() != 1 || !setterMethod.getParameters().get(0).getType().asErasure().represents(Object.class)) {
throw new IllegalArgumentException(setterMethod + " must declare a single Object-typed parameters");
}
return new Binder(getterMethod, setterMethod);
}
/**
* Extracts the only method from a given type description which is validated for the required properties for
* using the type as a proxy base type.
*
* @param typeDescription The type description to evaluate.
* @return The only method which was found to be compatible to the proxy requirements.
*/
private static MethodDescription onlyMethod(TypeDescription typeDescription) {
if (!typeDescription.isInterface()) {
throw new IllegalArgumentException(typeDescription + " is not an interface");
} else if (!typeDescription.getInterfaces().isEmpty()) {
throw new IllegalArgumentException(typeDescription + " must not extend other interfaces");
} else if (!typeDescription.isPublic()) {
throw new IllegalArgumentException(typeDescription + " is mot public");
}
MethodList methodCandidates = typeDescription.getDeclaredMethods().filter(isAbstract());
if (methodCandidates.size() != 1) {
throw new IllegalArgumentException(typeDescription + " must declare exactly one abstract method");
}
return methodCandidates.getOnly();
}
@Override
public Class getHandledType() {
return FieldProxy.class;
}
@Override
public MethodDelegationBinder.ParameterBinding bind(AnnotationDescription.Loadable annotation,
MethodDescription source,
ParameterDescription target,
Implementation.Target implementationTarget,
Assigner assigner) {
AccessType accessType;
if (target.getType().asErasure().equals(getterMethod.getDeclaringType())) {
accessType = AccessType.GETTER;
} else if (target.getType().asErasure().equals(setterMethod.getDeclaringType())) {
accessType = AccessType.SETTER;
} else {
throw new IllegalStateException(target + " uses a @Field annotation on an non-installed type");
}
FieldLocator.Resolution resolution = FieldLocator.of(annotation.getValue(FIELD_NAME, String.class), source)
.lookup(annotation.getValue(DEFINING_TYPE, TypeDescription.class), implementationTarget.getInstrumentedType())
.resolve(implementationTarget.getInstrumentedType(), source.isStatic());
return resolution.isValid()
? new MethodDelegationBinder.ParameterBinding.Anonymous(new AccessorProxy(
resolution.getFieldDescription(),
assigner,
implementationTarget.getInstrumentedType(),
accessType,
annotation.getValue(SERIALIZABLE_PROXY, Boolean.class)))
: MethodDelegationBinder.ParameterBinding.Illegal.INSTANCE;
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& getterMethod.equals(((Binder) other).getterMethod)
&& setterMethod.equals(((Binder) other).setterMethod);
}
@Override
public int hashCode() {
int result = getterMethod.hashCode();
result = 31 * result + setterMethod.hashCode();
return result;
}
@Override
public String toString() {
return "FieldProxy.Binder{" +
"getterMethod=" + getterMethod +
", setterMethod=" + setterMethod +
'}';
}
/**
* Represents an implementation for implementing a proxy type constructor when a static field is accessed.
*/
protected enum StaticFieldConstructor implements Implementation {
/**
* The singleton instance.
*/
INSTANCE;
/**
* A reference of the {@link Object} type default constructor.
*/
private final MethodDescription objectTypeDefaultConstructor;
/**
* Creates the constructor call singleton.
*/
StaticFieldConstructor() {
objectTypeDefaultConstructor = TypeDescription.OBJECT.getDeclaredMethods()
.filter(isConstructor())
.getOnly();
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType;
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new ByteCodeAppender.Simple(MethodVariableAccess.REFERENCE.loadOffset(0),
MethodInvocation.invoke(objectTypeDefaultConstructor),
MethodReturn.VOID);
}
@Override
public String toString() {
return "FieldProxy.Binder.StaticFieldConstructor." + name();
}
}
/**
* Determines the way a field is to be accessed.
*/
protected enum AccessType {
/**
* Represents getter access for a field.
*/
GETTER {
@Override
protected TypeDescription proxyType(MethodDescription getterMethod, MethodDescription setterMethod) {
return getterMethod.getDeclaringType().asErasure();
}
@Override
protected Implementation access(FieldDescription fieldDescription,
Assigner assigner,
AuxiliaryType.MethodAccessorFactory methodAccessorFactory) {
return new Getter(fieldDescription, assigner, methodAccessorFactory);
}
},
/**
* Represents setter access for a field.
*/
SETTER {
@Override
protected TypeDescription proxyType(MethodDescription getterMethod, MethodDescription setterMethod) {
return setterMethod.getDeclaringType().asErasure();
}
@Override
protected Implementation access(FieldDescription fieldDescription,
Assigner assigner,
AuxiliaryType.MethodAccessorFactory methodAccessorFactory) {
return new Setter(fieldDescription, assigner, methodAccessorFactory);
}
};
/**
* Locates the type to be implemented by a field accessor proxy.
*
* @param getterMethod The getter method to be implemented by a getter proxy.
* @param setterMethod The setter method to be implemented by a setter proxy.
* @return The correct proxy type for the represented sort of accessor.
*/
protected abstract TypeDescription proxyType(MethodDescription getterMethod, MethodDescription setterMethod);
/**
* Returns an implementation that implements the sort of accessor implementation that is represented by
* this instance.
*
* @param fieldDescription The field to be accessed.
* @param assigner The assigner to use.
* @param methodAccessorFactory The accessed type's method accessor factory.
* @return A suitable implementation.
*/
protected abstract Implementation access(FieldDescription fieldDescription,
Assigner assigner,
AuxiliaryType.MethodAccessorFactory methodAccessorFactory);
@Override
public String toString() {
return "FieldProxy.Binder.AccessType." + name();
}
/**
* Implementation for a getter method.
*/
protected static class Getter implements Implementation {
/**
* The field that is being accessed.
*/
private final FieldDescription accessedField;
/**
* The assigner to use.
*/
private final Assigner assigner;
/**
* The accessed type's method accessor factory.
*/
private final AuxiliaryType.MethodAccessorFactory methodAccessorFactory;
/**
* Creates a new getter implementation.
*
* @param accessedField The field that is being accessed.
* @param assigner The assigner to use.
* @param methodAccessorFactory The accessed type's method accessor factory.
*/
protected Getter(FieldDescription accessedField,
Assigner assigner,
AuxiliaryType.MethodAccessorFactory methodAccessorFactory) {
this.accessedField = accessedField;
this.assigner = assigner;
this.methodAccessorFactory = methodAccessorFactory;
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType;
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new Appender(implementationTarget);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
Getter getter = (Getter) other;
return accessedField.equals(getter.accessedField)
&& assigner.equals(getter.assigner)
&& methodAccessorFactory.equals(getter.methodAccessorFactory);
}
@Override
public int hashCode() {
int result = accessedField.hashCode();
result = 31 * result + assigner.hashCode();
result = 31 * result + methodAccessorFactory.hashCode();
return result;
}
@Override
public String toString() {
return "FieldProxy.Binder.AccessType.Getter{" +
"accessedField=" + accessedField +
", assigner=" + assigner +
", methodAccessorFactory=" + methodAccessorFactory +
'}';
}
/**
* A byte code appender for a getter method.
*/
protected class Appender implements ByteCodeAppender {
/**
* The generated accessor type.
*/
private final TypeDescription typeDescription;
/**
* Creates a new appender for a setter method.
*
* @param implementationTarget The implementation target of the current instrumentation.
*/
protected Appender(Target implementationTarget) {
typeDescription = implementationTarget.getInstrumentedType();
}
@Override
public Size apply(MethodVisitor methodVisitor,
Context implementationContext,
MethodDescription instrumentedMethod) {
MethodDescription getterMethod = methodAccessorFactory.registerGetterFor(accessedField);
StackManipulation.Size stackSize = new StackManipulation.Compound(
accessedField.isStatic()
? StackManipulation.Trivial.INSTANCE
: new StackManipulation.Compound(
MethodVariableAccess.REFERENCE.loadOffset(0),
FieldAccess.forField(typeDescription.getDeclaredFields()
.filter((named(AccessorProxy.FIELD_NAME))).getOnly()).getter()),
MethodInvocation.invoke(getterMethod),
assigner.assign(getterMethod.getReturnType(), instrumentedMethod.getReturnType(), Assigner.Typing.DYNAMIC),
MethodReturn.returning(instrumentedMethod.getReturnType().asErasure())
).apply(methodVisitor, implementationContext);
return new Size(stackSize.getMaximalSize(), instrumentedMethod.getStackSize());
}
/**
* Returns the outer instance.
*
* @return The outer instance.
*/
private Getter getOuter() {
return Getter.this;
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& Getter.this.equals(((Appender) other).getOuter())
&& typeDescription.equals(((Appender) other).typeDescription);
}
@Override
public int hashCode() {
return typeDescription.hashCode() + 31 * Getter.this.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.AccessType.Getter.Appender{" +
"getter=" + Getter.this +
"typeDescription=" + typeDescription +
'}';
}
}
}
/**
* Implementation for a setter method.
*/
protected static class Setter implements Implementation {
/**
* The field that is being accessed.
*/
private final FieldDescription accessedField;
/**
* The assigner to use.
*/
private final Assigner assigner;
/**
* The accessed type's method accessor factory.
*/
private final AuxiliaryType.MethodAccessorFactory methodAccessorFactory;
/**
* Creates a new setter implementation.
*
* @param accessedField The field that is being accessed.
* @param assigner The assigner to use.
* @param methodAccessorFactory The accessed type's method accessor factory.
*/
protected Setter(FieldDescription accessedField,
Assigner assigner,
AuxiliaryType.MethodAccessorFactory methodAccessorFactory) {
this.accessedField = accessedField;
this.assigner = assigner;
this.methodAccessorFactory = methodAccessorFactory;
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType;
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new Appender(implementationTarget);
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
Setter getter = (Setter) other;
return accessedField.equals(getter.accessedField)
&& assigner.equals(getter.assigner)
&& methodAccessorFactory.equals(getter.methodAccessorFactory);
}
@Override
public int hashCode() {
int result = accessedField.hashCode();
result = 31 * result + assigner.hashCode();
result = 31 * result + methodAccessorFactory.hashCode();
return result;
}
@Override
public String toString() {
return "FieldProxy.Binder.AccessType.Setter{" +
"accessedField=" + accessedField +
", assigner=" + assigner +
", methodAccessorFactory=" + methodAccessorFactory +
'}';
}
/**
* A byte code appender for a setter method.
*/
protected class Appender implements ByteCodeAppender {
/**
* The generated accessor type.
*/
private final TypeDescription typeDescription;
/**
* Creates a new appender for a setter method.
*
* @param implementationTarget The implementation target of the current instrumentation.
*/
protected Appender(Target implementationTarget) {
typeDescription = implementationTarget.getInstrumentedType();
}
@Override
public Size apply(MethodVisitor methodVisitor,
Context implementationContext,
MethodDescription instrumentedMethod) {
TypeDescription.Generic parameterType = instrumentedMethod.getParameters().get(0).getType();
MethodDescription setterMethod = methodAccessorFactory.registerSetterFor(accessedField);
StackManipulation.Size stackSize = new StackManipulation.Compound(
accessedField.isStatic()
? StackManipulation.Trivial.INSTANCE
: new StackManipulation.Compound(
MethodVariableAccess.REFERENCE.loadOffset(0),
FieldAccess.forField(typeDescription.getDeclaredFields()
.filter((named(AccessorProxy.FIELD_NAME))).getOnly()).getter()),
MethodVariableAccess.of(parameterType).loadOffset(1),
assigner.assign(parameterType, setterMethod.getParameters().get(0).getType(), Assigner.Typing.DYNAMIC),
MethodInvocation.invoke(setterMethod),
MethodReturn.VOID
).apply(methodVisitor, implementationContext);
return new Size(stackSize.getMaximalSize(), instrumentedMethod.getStackSize());
}
/**
* Returns the outer instance.
*
* @return The outer instance.
*/
private Setter getOuter() {
return Setter.this;
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& Setter.this.equals(((Appender) other).getOuter())
&& typeDescription.equals(((Appender) other).typeDescription);
}
@Override
public int hashCode() {
return typeDescription.hashCode() + 31 * Setter.this.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.AccessType.Setter.Appender{" +
"setter=" + Setter.this +
"typeDescription=" + typeDescription +
'}';
}
}
}
}
/**
* Represents an implementation for implementing a proxy type constructor when a non-static field is accessed.
*/
protected static class InstanceFieldConstructor implements Implementation {
/**
* The instrumented type from which a field is to be accessed.
*/
private final TypeDescription instrumentedType;
/**
* Creates a new implementation for implementing a field accessor proxy's constructor when accessing
* a non-static field.
*
* @param instrumentedType The instrumented type from which a field is to be accessed.
*/
protected InstanceFieldConstructor(TypeDescription instrumentedType) {
this.instrumentedType = instrumentedType;
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType.withField(new FieldDescription.Token(AccessorProxy.FIELD_NAME,
Opcodes.ACC_FINAL | Opcodes.ACC_PRIVATE,
this.instrumentedType.asGenericType()));
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new Appender(implementationTarget);
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& instrumentedType.equals(((InstanceFieldConstructor) other).instrumentedType);
}
@Override
public int hashCode() {
return instrumentedType.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.InstanceFieldConstructor{" +
"instrumentedType=" + instrumentedType +
'}';
}
/**
* An appender for implementing an
* {@link FieldProxy.Binder.InstanceFieldConstructor}.
*/
protected static class Appender implements ByteCodeAppender {
/**
* The field to be set within the constructor.
*/
private final FieldDescription fieldDescription;
/**
* Creates a new appender.
*
* @param implementationTarget The implementation target of the current implementation.
*/
protected Appender(Target implementationTarget) {
fieldDescription = implementationTarget.getInstrumentedType()
.getDeclaredFields()
.filter((named(AccessorProxy.FIELD_NAME)))
.getOnly();
}
@Override
public Size apply(MethodVisitor methodVisitor,
Context implementationContext,
MethodDescription instrumentedMethod) {
StackManipulation.Size stackSize = new StackManipulation.Compound(
MethodVariableAccess.REFERENCE.loadOffset(0),
MethodInvocation.invoke(StaticFieldConstructor.INSTANCE.objectTypeDefaultConstructor),
MethodVariableAccess.allArgumentsOf(instrumentedMethod.asDefined()).prependThisReference(),
FieldAccess.forField(fieldDescription).putter(),
MethodReturn.VOID
).apply(methodVisitor, implementationContext);
return new Size(stackSize.getMaximalSize(), instrumentedMethod.getStackSize());
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldDescription.equals(((Appender) other).fieldDescription);
}
@Override
public int hashCode() {
return fieldDescription.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.InstanceFieldConstructor.Appender{" +
"fieldDescription=" + fieldDescription +
'}';
}
}
}
/**
* A field locator is responsible for locating the type a field is defined in.
*/
protected abstract static class FieldLocator {
/**
* Returns a field locator for a given field.
*
* @param fieldName The field's name which might represent
* {@link FieldProxy#BEAN_PROPERTY}
* if the field's name should be derived from a method's name.
* @param methodDescription The intercepted method.
* @return An appropriate field locator.
*/
protected static FieldLocator of(String fieldName, MethodDescription methodDescription) {
return BEAN_PROPERTY.equals(fieldName)
? Legal.consider(methodDescription)
: new Legal(fieldName);
}
/**
* Locates a field of a given name on a specific type.
*
* @param typeDescription The type which defines the field or a representation of {@code void} for
* looking up a type implicitly within the type hierarchy.
* @param instrumentedType The instrumented type from which a field is to be accessed.
* @return A corresponding lookup engine.
*/
protected abstract LookupStrategy lookup(TypeDescription typeDescription, TypeDescription instrumentedType);
/**
* A resolution represents the result of a field location.
*/
protected abstract static class Resolution {
/**
* Determines if a field lookup was successful.
*
* @return {@code true} if a field lookup was successful.
*/
protected abstract boolean isValid();
/**
* Returns a description of the located field. This method must only be called for valid
* resolutions.
*
* @return The located field.
*/
protected abstract FieldDescription getFieldDescription();
/**
* A resolution for a non-located field.
*/
protected static class Unresolved extends Resolution {
@Override
protected boolean isValid() {
return false;
}
@Override
protected FieldDescription getFieldDescription() {
throw new IllegalStateException("Cannot resolve an unresolved field lookup");
}
@Override
public int hashCode() {
return 17;
}
@Override
public boolean equals(Object other) {
return other == this || (other != null && other.getClass() == getClass());
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.Resolution.Unresolved{}";
}
}
/**
* A resolution for a successfully located field.
*/
protected static class Resolved extends Resolution {
/**
* The located field.
*/
private final FieldDescription fieldDescription;
/**
* Creates a new successful resolution.
*
* @param fieldDescription The located field.
*/
protected Resolved(FieldDescription fieldDescription) {
this.fieldDescription = fieldDescription;
}
@Override
protected boolean isValid() {
return true;
}
@Override
protected FieldDescription getFieldDescription() {
return fieldDescription;
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldDescription.equals(((Resolved) other).fieldDescription);
}
@Override
public int hashCode() {
return fieldDescription.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.Resolution.Resolved{" +
"fieldDescription=" + fieldDescription +
'}';
}
}
}
/**
* A lookup engine is responsible for finding a specific field in a type hierarchy.
*/
protected abstract static class LookupStrategy {
/**
* Locates a field if possible and returns a corresponding resolution.
*
* @param instrumentedType The instrumented type from which a field is to be accessed.
* @param staticMethod {@code true} if the intercepted method is static.
* @return A resolution of the field name lookup.
*/
protected abstract Resolution resolve(TypeDescription instrumentedType, boolean staticMethod);
/**
* Represents a lookup engine that can only produce illegal look-ups.
*/
protected static class Illegal extends LookupStrategy {
@Override
protected Resolution resolve(TypeDescription instrumentedType, boolean staticMethod) {
return new Resolution.Unresolved();
}
@Override
public int hashCode() {
return 17;
}
@Override
public boolean equals(Object other) {
return other == this || (other != null && other.getClass() == getClass());
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.LookupStrategy.Illegal{}";
}
}
/**
* Represents a lookup engine that tries to find the most specific field in a class hierarchy.
*/
protected static class ForHierarchy extends LookupStrategy {
/**
* The name of the field to be found.
*/
private final String fieldName;
/**
* Creates a new lookup engine that looks up a field name within the class hierarchy of the
* instrumented type.
*
* @param fieldName The name of the field to be found.
*/
protected ForHierarchy(String fieldName) {
this.fieldName = fieldName;
}
@Override
protected Resolution resolve(TypeDescription instrumentedType, boolean staticMethod) {
for (TypeDefinition currentType : instrumentedType) {
FieldList fieldList = currentType.getDeclaredFields().filter(named(fieldName).and(isVisibleTo(instrumentedType)));
if (fieldList.size() > 1) {
throw new IllegalStateException("Ambiguous fields: " + fieldList);
} else if (!fieldList.isEmpty() && (!staticMethod || fieldList.getOnly().isStatic())) {
return new Resolution.Resolved(fieldList.getOnly());
}
}
return new Resolution.Unresolved();
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldName.equals(((ForHierarchy) other).fieldName);
}
@Override
public int hashCode() {
return fieldName.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.LookupStrategy.ForHierarchy{" +
"fieldName='" + fieldName + '\'' +
'}';
}
}
/**
* Represents a lookup engine that tries to find a field for a given type.
*/
protected static class ForExplicitType extends LookupStrategy {
/**
* The name of the field.
*/
private final String fieldName;
/**
* The type which is supposed to define a field with the given field name.
*/
private final TypeDescription typeDescription;
/**
* Creates a new lookup engine for a given type.
*
* @param fieldName The name of the field to be found.
* @param typeDescription The type which is supposed to define a field with the given field name.
*/
protected ForExplicitType(String fieldName, TypeDescription typeDescription) {
this.fieldName = fieldName;
this.typeDescription = typeDescription;
}
@Override
protected Resolution resolve(TypeDescription instrumentedType, boolean staticMethod) {
FieldList fieldList = typeDescription.getDeclaredFields().filter(named(fieldName).and(isVisibleTo(instrumentedType)));
if (fieldList.size() > 1) {
throw new IllegalStateException("Ambiguous fields: " + fieldList);
}
return !fieldList.isEmpty() && (!staticMethod || fieldList.getOnly().isStatic())
? new Resolution.Resolved(fieldList.getOnly())
: new Resolution.Unresolved();
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldName.equals(((ForExplicitType) other).fieldName)
&& typeDescription.equals(((ForExplicitType) other).typeDescription);
}
@Override
public int hashCode() {
int result = fieldName.hashCode();
result = 31 * result + typeDescription.hashCode();
return result;
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.LookupStrategy.ForExplicitType{" +
"fieldName='" + fieldName + '\'' +
", typeDescription=" + typeDescription +
'}';
}
}
}
/**
* Represents a field locator for a field whose name could be located.
*/
protected static class Legal extends FieldLocator {
/**
* The name of the field.
*/
private final String fieldName;
/**
* Creates a new field locator for a legal field name.
*
* @param fieldName The name of the field.
*/
protected Legal(String fieldName) {
this.fieldName = fieldName;
}
/**
* Considers a given method to expose a field name by following the Java bean naming conventions
* for getter and setter methods.
*
* @param methodDescription The method to consider for such a field name identification.
* @return A corresponding field name locator.
*/
protected static FieldLocator consider(MethodDescription methodDescription) {
String fieldName;
if (isSetter().matches(methodDescription)) {
fieldName = methodDescription.getInternalName().substring(3);
} else if (isGetter().matches(methodDescription)) {
fieldName = methodDescription.getInternalName().substring(methodDescription.getInternalName().startsWith("is") ? 2 : 3);
} else {
return new Illegal();
}
return new Legal(Character.toLowerCase(fieldName.charAt(0)) + fieldName.substring(1));
}
@Override
protected LookupStrategy lookup(TypeDescription typeDescription, TypeDescription instrumentedType) {
return typeDescription.represents(void.class)
? new LookupStrategy.ForHierarchy(fieldName)
: new LookupStrategy.ForExplicitType(fieldName, TargetType.resolve(typeDescription, instrumentedType));
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldName.equals(((Legal) other).fieldName);
}
@Override
public int hashCode() {
return fieldName.hashCode();
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.Legal{" +
"fieldName='" + fieldName + '\'' +
'}';
}
}
/**
* Represents an illegal field locator which can impossible locate a field.
*/
protected static class Illegal extends FieldLocator {
@Override
protected LookupStrategy lookup(TypeDescription typeDescription, TypeDescription instrumentedType) {
return new LookupStrategy.Illegal();
}
@Override
public int hashCode() {
return 31;
}
@Override
public boolean equals(Object other) {
return other == this || (other != null && other.getClass() == getClass());
}
@Override
public String toString() {
return "FieldProxy.Binder.FieldLocator.Illegal{}";
}
}
}
/**
* A proxy type for accessing a field either by a getter or a setter.
*/
protected class AccessorProxy implements AuxiliaryType, StackManipulation {
/**
* The name of the field that stores the accessed instance if any.
*/
protected static final String FIELD_NAME = "instance";
/**
* The field that is being accessed.
*/
private final FieldDescription accessedField;
/**
* The type which is accessed.
*/
private final TypeDescription instrumentedType;
/**
* The assigner to use.
*/
private final Assigner assigner;
/**
* The access type to implement.
*/
private final AccessType accessType;
/**
* {@code true} if the generated proxy should be serializable.
*/
private final boolean serializableProxy;
/**
* @param accessedField The field that is being accessed.
* @param assigner The assigner to use.
* @param instrumentedType The type which is accessed.
* @param accessType The assigner to use.
* @param serializableProxy {@code true} if the generated proxy should be serializable.
*/
protected AccessorProxy(FieldDescription accessedField,
Assigner assigner,
TypeDescription instrumentedType,
AccessType accessType,
boolean serializableProxy) {
this.accessedField = accessedField;
this.assigner = assigner;
this.instrumentedType = instrumentedType;
this.accessType = accessType;
this.serializableProxy = serializableProxy;
}
@Override
public DynamicType make(String auxiliaryTypeName,
ClassFileVersion classFileVersion,
MethodAccessorFactory methodAccessorFactory) {
return new ByteBuddy(classFileVersion)
.subclass(accessType.proxyType(getterMethod, setterMethod), ConstructorStrategy.Default.NO_CONSTRUCTORS)
.name(auxiliaryTypeName)
.modifiers(DEFAULT_TYPE_MODIFIER)
.implement(serializableProxy ? new Class[]{Serializable.class} : new Class[0])
.defineConstructor().withParameters(accessedField.isStatic()
? Collections.emptyList()
: Collections.singletonList(instrumentedType))
.intercept(accessedField.isStatic()
? StaticFieldConstructor.INSTANCE
: new InstanceFieldConstructor(instrumentedType))
.method(isDeclaredBy(accessType.proxyType(getterMethod, setterMethod)))
.intercept(accessType.access(accessedField, assigner, methodAccessorFactory))
.make();
}
@Override
public boolean isValid() {
return true;
}
@Override
public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext) {
TypeDescription auxiliaryType = implementationContext.register(this);
return new Compound(
TypeCreation.of(auxiliaryType),
Duplication.SINGLE,
accessedField.isStatic()
? Trivial.INSTANCE
: MethodVariableAccess.REFERENCE.loadOffset(0),
MethodInvocation.invoke(auxiliaryType.getDeclaredMethods().filter(isConstructor()).getOnly())
).apply(methodVisitor, implementationContext);
}
/**
* Returns the outer instance.
*
* @return The outer instance.
*/
private Binder getOuter() {
return Binder.this;
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
AccessorProxy that = (AccessorProxy) other;
return serializableProxy == that.serializableProxy
&& accessType == that.accessType
&& accessedField.equals(that.accessedField)
&& assigner.equals(that.assigner)
&& Binder.this.equals(that.getOuter())
&& instrumentedType.equals(that.instrumentedType);
}
@Override
public int hashCode() {
int result = accessedField.hashCode();
result = 31 * result + instrumentedType.hashCode();
result = 31 * result + assigner.hashCode();
result = 31 * result + Binder.this.hashCode();
result = 31 * result + accessType.hashCode();
result = 31 * result + (serializableProxy ? 1 : 0);
return result;
}
@Override
public String toString() {
return "FieldProxy.Binder.AccessorProxy{" +
"accessedField=" + accessedField +
", instrumentedType=" + instrumentedType +
", assigner=" + assigner +
", accessType=" + accessType +
", serializableProxy=" + serializableProxy +
", binder=" + Binder.this +
'}';
}
}
}
}
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