com.fitbur.mockito.bytebuddy.implementation.FieldAccessor Maven / Gradle / Ivy
package com.fitbur.mockito.bytebuddy.implementation;
import com.fitbur.mockito.bytebuddy.description.field.FieldDescription;
import com.fitbur.mockito.bytebuddy.description.method.MethodDescription;
import com.fitbur.mockito.bytebuddy.description.modifier.ModifierContributor;
import com.fitbur.mockito.bytebuddy.description.type.TypeDefinition;
import com.fitbur.mockito.bytebuddy.description.type.TypeDescription;
import com.fitbur.mockito.bytebuddy.dynamic.TargetType;
import com.fitbur.mockito.bytebuddy.dynamic.scaffold.FieldLocator;
import com.fitbur.mockito.bytebuddy.dynamic.scaffold.InstrumentedType;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.ByteCodeAppender;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.StackManipulation;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.assign.Assigner;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.member.FieldAccess;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.member.MethodReturn;
import com.fitbur.mockito.bytebuddy.implementation.bytecode.member.MethodVariableAccess;
import com.fitbur.mockito.bytebuddy.jar.asm.MethodVisitor;
import com.fitbur.mockito.bytebuddy.jar.asm.Opcodes;
import java.lang.reflect.Type;
import static com.fitbur.mockito.bytebuddy.matcher.ElementMatchers.*;
/**
* Defines a method to access a given field by following the Java bean conventions for getters and setters:
*
* - Getter: A method named {@code getFoo()} will be instrumented to read and return the value of a field {@code foo}
* or another field if one was specified explicitly. If a property is of type {@link java.lang.Boolean} or
* {@code boolean}, the name {@code isFoo()} is also permitted.
* - Setter: A method named {@code setFoo(value)} will be instrumented to write the given argument {@code value}
* to a field {@code foo} or to another field if one was specified explicitly.
*
*/
public abstract class FieldAccessor implements Implementation {
/**
* The assigner to use.
*/
protected final Assigner assigner;
/**
* Indicates if dynamic type castings should be attempted for incompatible assignments.
*/
protected final Assigner.Typing typing;
/**
* Creates a new field accessor.
*
* @param assigner The assigner to use.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
*/
protected FieldAccessor(Assigner assigner, Assigner.Typing typing) {
this.assigner = assigner;
this.typing = typing;
}
/**
* Defines a field accessor where any access is targeted to a field named {@code name}.
*
* @param name The name of the field to be accessed.
* @return A field accessor for a field of a given name.
*/
public static FieldDefinable ofField(String name) {
return new ForNamedField(Assigner.DEFAULT, Assigner.Typing.STATIC, name);
}
/**
* Defines a field accessor where any access is targeted to a field that matches the methods
* name with the Java specification for bean properties, i.e. a method {@code getFoo} or {@code setFoo(value)}
* will either read or write a field named {@code foo}.
*
* @return A field accessor that follows the Java naming conventions for bean properties.
*/
public static OwnerTypeLocatable ofBeanProperty() {
return of(FieldNameExtractor.ForBeanProperty.INSTANCE);
}
/**
* Defines a custom strategy for determining the field that is accessed by this field accessor.
*
* @param fieldNameExtractor The field name extractor to use.
* @return A field accessor using the given field name extractor.
*/
public static OwnerTypeLocatable of(FieldNameExtractor fieldNameExtractor) {
return new ForUnnamedField(Assigner.DEFAULT, Assigner.Typing.STATIC, fieldNameExtractor);
}
/**
* Applies a field getter implementation.
*
* @param methodVisitor The method visitor to write any instructions to.
* @param implementationContext The implementation context of the current implementation.
* @param fieldDescription The description of the field to read.
* @param methodDescription The method that is target of the implementation.
* @return The required size of the operand stack and local variable array for this implementation.
*/
protected ByteCodeAppender.Size applyGetter(MethodVisitor methodVisitor,
Implementation.Context implementationContext,
FieldDescription fieldDescription,
MethodDescription methodDescription) {
StackManipulation stackManipulation = assigner.assign(fieldDescription.getType(), methodDescription.getReturnType(), typing);
if (!stackManipulation.isValid()) {
throw new IllegalStateException("Getter type of " + methodDescription + " is not compatible with " + fieldDescription);
}
return apply(methodVisitor,
implementationContext,
fieldDescription,
methodDescription,
new StackManipulation.Compound(
FieldAccess.forField(fieldDescription).getter(),
stackManipulation
)
);
}
/**
* Applies a field setter implementation.
*
* @param methodVisitor The method visitor to write any instructions to.
* @param implementationContext The implementation context of the current implementation.
* @param fieldDescription The description of the field to write to.
* @param methodDescription The method that is target of the instrumentation.
* @return The required size of the operand stack and local variable array for this implementation.
*/
protected ByteCodeAppender.Size applySetter(MethodVisitor methodVisitor,
Implementation.Context implementationContext,
FieldDescription fieldDescription,
MethodDescription methodDescription) {
StackManipulation stackManipulation = assigner.assign(methodDescription.getParameters().get(0).getType(), fieldDescription.getType(), typing);
if (!stackManipulation.isValid()) {
throw new IllegalStateException("Setter type of " + methodDescription + " is not compatible with " + fieldDescription);
} else if (fieldDescription.isFinal()) {
throw new IllegalArgumentException("Cannot apply setter on final field " + fieldDescription);
}
return apply(methodVisitor,
implementationContext,
fieldDescription,
methodDescription,
new StackManipulation.Compound(
MethodVariableAccess.of(fieldDescription.getType().asErasure())
.loadOffset(methodDescription.getParameters().get(0).getOffset()),
stackManipulation,
FieldAccess.forField(fieldDescription).putter()
)
);
}
/**
* A generic implementation of the application of a {@link com.fitbur.mockito.bytebuddy.implementation.bytecode.ByteCodeAppender}.
*
* @param methodVisitor The method visitor to write any instructions to.
* @param implementationContext The implementation context of the current implementation.
* @param fieldDescription The description of the field to access.
* @param methodDescription The method that is target of the implementation.
* @param fieldAccess The manipulation that represents the field access.
* @return A suitable {@link com.fitbur.mockito.bytebuddy.implementation.bytecode.ByteCodeAppender}.
*/
private ByteCodeAppender.Size apply(MethodVisitor methodVisitor,
Implementation.Context implementationContext,
FieldDescription fieldDescription,
MethodDescription methodDescription,
StackManipulation fieldAccess) {
if (methodDescription.isStatic() && !fieldDescription.isStatic()) {
throw new IllegalArgumentException("Cannot call instance field "
+ fieldDescription + " from static method " + methodDescription);
}
StackManipulation.Size stackSize = new StackManipulation.Compound(
fieldDescription.isStatic()
? StackManipulation.Trivial.INSTANCE
: MethodVariableAccess.REFERENCE.loadOffset(0),
fieldAccess,
MethodReturn.returning(methodDescription.getReturnType().asErasure())
).apply(methodVisitor, implementationContext);
return new ByteCodeAppender.Size(stackSize.getMaximalSize(), methodDescription.getStackSize());
}
/**
* Locates a field's name.
*
* @param targetMethod The method that is target of the implementation.
* @return The name of the field to be located for this implementation.
*/
protected abstract String getFieldName(MethodDescription targetMethod);
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& typing == ((FieldAccessor) other).typing
&& assigner.equals(((FieldAccessor) other).assigner);
}
@Override
public int hashCode() {
return 31 * assigner.hashCode() + typing.hashCode();
}
/**
* A field name extractor is responsible for determining a field name to a method that is implemented
* to access this method.
*/
public interface FieldNameExtractor {
/**
* Extracts a field name to be accessed by a getter or setter method.
*
* @param methodDescription The method for which a field name is to be determined.
* @return The name of the field to be accessed by this method.
*/
String fieldNameFor(MethodDescription methodDescription);
/**
* A {@link com.fitbur.mockito.bytebuddy.implementation.FieldAccessor.FieldNameExtractor} that determines a field name
* according to the rules of Java bean naming conventions.
*/
enum ForBeanProperty implements FieldNameExtractor {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public String fieldNameFor(MethodDescription methodDescription) {
String name = methodDescription.getInternalName();
int crop;
if (name.startsWith("get") || name.startsWith("set")) {
crop = 3;
} else if (name.startsWith("is")) {
crop = 2;
} else {
throw new IllegalArgumentException(methodDescription + " does not follow Java bean naming conventions");
}
name = name.substring(crop);
if (name.length() == 0) {
throw new IllegalArgumentException(methodDescription + " does not specify a bean name");
}
return Character.toLowerCase(name.charAt(0)) + name.substring(1);
}
@Override
public String toString() {
return "FieldAccessor.FieldNameExtractor.ForBeanProperty." + name();
}
}
}
/**
* A field accessor that can be configured to use a given assigner and runtime type use configuration.
*/
public interface AssignerConfigurable extends Implementation {
/**
* Returns a field accessor that is identical to this field accessor but uses the given assigner
* and runtime type use configuration.
*
* @param assigner The assigner to use.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
* @return This field accessor with the given assigner and runtime type use configuration.
*/
Implementation withAssigner(Assigner assigner, Assigner.Typing typing);
}
/**
* A field accessor that can be configured to locate a field in a specific manner.
*/
public interface OwnerTypeLocatable extends AssignerConfigurable {
/**
* Determines that a field should only be considered when it was defined in a given type.
*
* @param type The type to be considered.
* @return This field accessor which will only considered fields that are defined in the given type.
*/
AssignerConfigurable in(Class type);
/**
* Determines that a field should only be considered when it was defined in a given type.
*
* @param typeDescription A description of the type to be considered.
* @return This field accessor which will only considered fields that are defined in the given type.
*/
AssignerConfigurable in(TypeDescription typeDescription);
/**
* Determines that a field should only be considered when it was identified by a field locator that is
* produced by the given factory.
*
* @param factory A factory that will produce a field locator that will be used to find locate
* a field to be accessed.
* @return This field accessor which will only considered fields that are defined in the given type.
*/
AssignerConfigurable in(FieldLocator.Factory factory);
}
/**
* Determines a field accessor that accesses a field of a given name which might not yet be
* defined.
*/
public interface FieldDefinable extends OwnerTypeLocatable {
/**
* Defines a field with the given name in the instrumented type.
*
* @param type The type of the field.
* @param modifier The modifiers for the field.
* @return A field accessor that defines a field of the given type.
*/
AssignerConfigurable defineAs(Type type, ModifierContributor.ForField... modifier);
/**
* Defines a field with the given name in the instrumented type.
*
* @param typeDefinition The type of the field.
* @param modifier The modifiers for the field.
* @return A field accessor that defines a field of the given type.
*/
AssignerConfigurable defineAs(TypeDefinition typeDefinition, ModifierContributor.ForField... modifier);
}
/**
* Implementation of a field accessor implementation where a field is identified by a method's name following
* the Java specification for bean properties.
*/
protected static class ForUnnamedField extends FieldAccessor implements OwnerTypeLocatable {
/**
* A factory for creating a field locator for implementing this field accessor.
*/
private final FieldLocator.Factory fieldLocatorFactory;
/**
* The field name extractor to be used.
*/
private final FieldNameExtractor fieldNameExtractor;
/**
* Creates a new field accessor implementation.
*
* @param assigner The assigner to use.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
* @param fieldNameExtractor The field name extractor to use.
*/
protected ForUnnamedField(Assigner assigner, Assigner.Typing typing, FieldNameExtractor fieldNameExtractor) {
this(assigner, typing, fieldNameExtractor, FieldLocator.ForClassHierarchy.Factory.INSTANCE);
}
/**
* Creates a new field accessor implementation.
*
* @param assigner The assigner to use.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
* @param fieldNameExtractor The field name extractor to use.
* @param fieldLocatorFactory A factory that will produce a field locator that will be used to find locate
* a field to be accessed.
*/
protected ForUnnamedField(Assigner assigner,
Assigner.Typing typing,
FieldNameExtractor fieldNameExtractor,
FieldLocator.Factory fieldLocatorFactory) {
super(assigner, typing);
this.fieldNameExtractor = fieldNameExtractor;
this.fieldLocatorFactory = fieldLocatorFactory;
}
@Override
public AssignerConfigurable in(FieldLocator.Factory factory) {
return new ForUnnamedField(assigner, typing, fieldNameExtractor, factory);
}
@Override
public AssignerConfigurable in(Class type) {
return in(new TypeDescription.ForLoadedType(type));
}
@Override
public AssignerConfigurable in(TypeDescription typeDescription) {
return typeDescription.represents(TargetType.class)
? in(FieldLocator.ForClassHierarchy.Factory.INSTANCE)
: in(new FieldLocator.ForExactType.Factory(typeDescription));
}
@Override
public Implementation withAssigner(Assigner assigner, Assigner.Typing typing) {
return new ForUnnamedField(assigner, typing, fieldNameExtractor, fieldLocatorFactory);
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType;
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new Appender(fieldLocatorFactory.make(implementationTarget.getInstrumentedType()));
}
@Override
protected String getFieldName(MethodDescription targetMethod) {
return fieldNameExtractor.fieldNameFor(targetMethod);
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& super.equals(other)
&& fieldNameExtractor.equals(((ForUnnamedField) other).fieldNameExtractor)
&& fieldLocatorFactory.equals(((ForUnnamedField) other).fieldLocatorFactory);
}
@Override
public int hashCode() {
return 31 * (31 * super.hashCode() + fieldLocatorFactory.hashCode()) + fieldNameExtractor.hashCode();
}
@Override
public String toString() {
return "FieldAccessor.ForUnnamedField{" +
"assigner=" + assigner +
", typing=" + typing +
", fieldLocatorFactory=" + fieldLocatorFactory +
", fieldNameExtractor=" + fieldNameExtractor +
'}';
}
}
/**
* Implementation of a field accessor implementation where the field name is given explicitly.
*/
protected static class ForNamedField extends FieldAccessor implements FieldDefinable {
/**
* The name of the field that is accessed.
*/
private final String fieldName;
/**
* The preparation handler for implementing this field accessor.
*/
private final PreparationHandler preparationHandler;
/**
* The field locator factory for implementing this field accessor.
*/
private final FieldLocator.Factory fieldLocatorFactory;
/**
* Creates a field accessor implementation for a field of a given name.
*
* @param assigner The assigner to use.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
* @param fieldName The name of the field.
*/
protected ForNamedField(Assigner assigner, Assigner.Typing typing, String fieldName) {
super(assigner, typing);
this.fieldName = fieldName;
preparationHandler = PreparationHandler.NoOp.INSTANCE;
fieldLocatorFactory = FieldLocator.ForClassHierarchy.Factory.INSTANCE;
}
/**
* reates a field accessor implementation for a field of a given name.
*
* @param fieldName The name of the field.
* @param typing Indicates if dynamic type castings should be attempted for incompatible assignments.
* @param preparationHandler The preparation handler for potentially defining a field.
* @param fieldLocatorFactory A factory that will produce a field locator that will be used to find locate
* a field to be accessed.
* @param assigner The assigner to use.
*/
private ForNamedField(Assigner assigner,
Assigner.Typing typing,
String fieldName,
PreparationHandler preparationHandler,
FieldLocator.Factory fieldLocatorFactory) {
super(assigner, typing);
this.fieldName = fieldName;
this.preparationHandler = preparationHandler;
this.fieldLocatorFactory = fieldLocatorFactory;
}
@Override
public AssignerConfigurable defineAs(Type type, ModifierContributor.ForField... modifier) {
return defineAs(TypeDefinition.Sort.describe(type), modifier);
}
@Override
public AssignerConfigurable defineAs(TypeDefinition typeDefinition, ModifierContributor.ForField... modifier) {
return new ForNamedField(assigner,
typing,
fieldName,
PreparationHandler.FieldDefiner.of(fieldName, typeDefinition.asGenericType(), modifier),
FieldLocator.ForClassHierarchy.Factory.INSTANCE);
}
@Override
public AssignerConfigurable in(FieldLocator.Factory factory) {
return new ForNamedField(assigner,
typing,
fieldName,
preparationHandler,
factory);
}
@Override
public AssignerConfigurable in(Class type) {
return in(new TypeDescription.ForLoadedType(type));
}
@Override
public AssignerConfigurable in(TypeDescription typeDescription) {
return typeDescription.represents(TargetType.class)
? in(FieldLocator.ForClassHierarchy.Factory.INSTANCE)
: in(new FieldLocator.ForExactType.Factory(typeDescription));
}
@Override
public Implementation withAssigner(Assigner assigner, Assigner.Typing typing) {
return new ForNamedField(assigner,
typing,
fieldName,
preparationHandler,
fieldLocatorFactory);
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return preparationHandler.prepare(instrumentedType);
}
@Override
public ByteCodeAppender appender(Target implementationTarget) {
return new Appender(fieldLocatorFactory.make(implementationTarget.getInstrumentedType()));
}
@Override
protected String getFieldName(MethodDescription targetMethod) {
return fieldName;
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
if (!super.equals(other)) return false;
ForNamedField that = (ForNamedField) other;
return fieldLocatorFactory.equals(that.fieldLocatorFactory)
&& fieldName.equals(that.fieldName)
&& preparationHandler.equals(that.preparationHandler);
}
@Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + fieldName.hashCode();
result = 31 * result + preparationHandler.hashCode();
result = 31 * result + fieldLocatorFactory.hashCode();
return result;
}
@Override
public String toString() {
return "FieldAccessor.ForNamedField{" +
"assigner=" + assigner +
", fieldName='" + fieldName + '\'' +
", typing=" + typing +
", preparationHandler=" + preparationHandler +
", fieldLocatorFactory=" + fieldLocatorFactory +
'}';
}
/**
* A preparation handler is responsible for defining a field value on an implementation, if necessary.
*/
protected interface PreparationHandler {
/**
* Prepares the instrumented type.
*
* @param instrumentedType The instrumented type to be prepared.
* @return The readily prepared instrumented type.
*/
InstrumentedType prepare(InstrumentedType instrumentedType);
/**
* A non-operational preparation handler that does not alter the field.
*/
enum NoOp implements PreparationHandler {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
return instrumentedType;
}
@Override
public String toString() {
return "FieldAccessor.ForNamedField.PreparationHandler.NoOp." + name();
}
}
/**
* A preparation handler that actually defines a field on an instrumented type.
*/
class FieldDefiner implements PreparationHandler {
/**
* The name of the field that is defined by this preparation handler.
*/
private final String name;
/**
* The type of the field that is to be defined.
*/
private final TypeDescription.Generic typeDescription;
/**
* The modifier of the field that is to be defined.
*/
private final int modifiers;
/**
* Creates a new field definer.
*
* @param name The name of the field that is defined by this preparation handler.
* @param typeDescription The type of the field that is to be defined.
* @param modifiers The modifiers of the field that is to be defined.
*/
protected FieldDefiner(String name, TypeDescription.Generic typeDescription, int modifiers) {
this.name = name;
this.typeDescription = typeDescription;
this.modifiers = modifiers;
}
/**
* Creates a new preparation handler that defines a given field.
*
* @param name The name of the field that is defined by this preparation handler.
* @param typeDescription The type of the field that is to be defined.
* @param contributor The modifiers of the field that is to be defined.
* @return A corresponding preparation handler.
*/
public static PreparationHandler of(String name, TypeDescription.Generic typeDescription, ModifierContributor.ForField... contributor) {
return new FieldDefiner(name, typeDescription, ModifierContributor.Resolver.of(contributor).resolve());
}
@Override
public InstrumentedType prepare(InstrumentedType instrumentedType) {
if (instrumentedType.isInterface() && ((modifiers & Opcodes.ACC_PUBLIC) == 0 || (modifiers & Opcodes.ACC_STATIC) == 0)) {
throw new IllegalStateException("Cannot define a non-public, non-static field for " + instrumentedType);
}
return instrumentedType.withField(new FieldDescription.Token(name, modifiers, typeDescription));
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
FieldDefiner that = (FieldDefiner) other;
return modifiers == that.modifiers
&& name.equals(that.name)
&& typeDescription.equals(that.typeDescription);
}
@Override
public int hashCode() {
int result = name.hashCode();
result = 31 * result + typeDescription.hashCode();
result = 31 * result + modifiers;
return result;
}
@Override
public String toString() {
return "FieldAccessor.ForNamedField.PreparationHandler.FieldDefiner{" +
"name='" + name + '\'' +
", typeDescription=" + typeDescription +
", modifiers=" + modifiers +
'}';
}
}
}
}
/**
* An byte code appender for an field accessor implementation.
*/
protected class Appender implements ByteCodeAppender {
/**
* The field locator for implementing this appender.
*/
private final FieldLocator fieldLocator;
/**
* Creates a new byte code appender for a field accessor implementation.
*
* @param fieldLocator The field locator for this byte code appender.
*/
protected Appender(FieldLocator fieldLocator) {
this.fieldLocator = fieldLocator;
}
@Override
public Size apply(MethodVisitor methodVisitor,
Implementation.Context implementationContext,
MethodDescription instrumentedMethod) {
if (isConstructor().matches(instrumentedMethod)) {
throw new IllegalArgumentException("Constructors cannot define beans: " + instrumentedMethod);
}
FieldLocator.Resolution resolution = fieldLocator.locate(getFieldName(instrumentedMethod));
if (!resolution.isResolved() || (instrumentedMethod.isStatic() && !resolution.getField().isStatic())) {
throw new IllegalStateException("Cannot locate accessible field for " + instrumentedMethod);
}
if (takesArguments(0).and(not(returns(void.class))).matches(instrumentedMethod)) {
return applyGetter(methodVisitor,
implementationContext,
resolution.getField(),
instrumentedMethod);
} else if (takesArguments(1).and(returns(void.class)).matches(instrumentedMethod)) {
return applySetter(methodVisitor,
implementationContext,
resolution.getField(),
instrumentedMethod);
} else {
throw new IllegalArgumentException("Method " + implementationContext + " is no bean property");
}
}
/**
* Returns the outer instance.
*
* @return The outer instance.
*/
private FieldAccessor getFieldAccessor() {
return FieldAccessor.this;
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& fieldLocator.equals(((Appender) other).fieldLocator)
&& FieldAccessor.this.equals(((Appender) other).getFieldAccessor());
}
@Override
public int hashCode() {
return 31 * FieldAccessor.this.hashCode() + fieldLocator.hashCode();
}
@Override
public String toString() {
return "FieldAccessor.Appender{" +
"fieldLocator=" + fieldLocator +
"fieldAccessor=" + FieldAccessor.this +
'}';
}
}
}
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