/**
* Copyright (C) 2008 Google Inc.
*
* 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 com.google.inject.spi;
import static com.google.inject.internal.MoreTypes.getRawType;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.inject.ConfigurationException;
import com.google.inject.Inject;
import com.google.inject.Key;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.Annotations;
import com.google.inject.internal.Errors;
import com.google.inject.internal.ErrorsException;
import com.google.inject.internal.Nullability;
import com.google.inject.internal.util.Classes;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A constructor, field or method that can receive injections. Typically this is a member with the
* {@literal @}{@link Inject} annotation. For non-private, no argument constructors, the member may
* omit the annotation.
*
* @author crazybob@google.com (Bob Lee)
* @since 2.0
*/
public final class InjectionPoint {
private static final Logger logger = Logger.getLogger(InjectionPoint.class.getName());
private final boolean optional;
private final Member member;
private final TypeLiteral<?> declaringType;
private final ImmutableList<Dependency<?>> dependencies;
InjectionPoint(TypeLiteral<?> declaringType, Method method, boolean optional) {
this.member = method;
this.declaringType = declaringType;
this.optional = optional;
this.dependencies = forMember(method, declaringType, method.getParameterAnnotations());
}
InjectionPoint(TypeLiteral<?> declaringType, Constructor<?> constructor) {
this.member = constructor;
this.declaringType = declaringType;
this.optional = false;
this.dependencies = forMember(
constructor, declaringType, constructor.getParameterAnnotations());
}
InjectionPoint(TypeLiteral<?> declaringType, Field field, boolean optional) {
this.member = field;
this.declaringType = declaringType;
this.optional = optional;
Annotation[] annotations = field.getAnnotations();
Errors errors = new Errors(field);
Key<?> key = null;
try {
key = Annotations.getKey(declaringType.getFieldType(field), field, annotations, errors);
} catch (ConfigurationException e) {
errors.merge(e.getErrorMessages());
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
errors.throwConfigurationExceptionIfErrorsExist();
this.dependencies = ImmutableList.<Dependency<?>>of(
newDependency(key, Nullability.allowsNull(annotations), -1));
}
private ImmutableList<Dependency<?>> forMember(Member member, TypeLiteral<?> type,
Annotation[][] paramterAnnotations) {
Errors errors = new Errors(member);
Iterator<Annotation[]> annotationsIterator = Arrays.asList(paramterAnnotations).iterator();
List<Dependency<?>> dependencies = Lists.newArrayList();
int index = 0;
for (TypeLiteral<?> parameterType : type.getParameterTypes(member)) {
try {
Annotation[] parameterAnnotations = annotationsIterator.next();
Key<?> key = Annotations.getKey(parameterType, member, parameterAnnotations, errors);
dependencies.add(newDependency(key, Nullability.allowsNull(parameterAnnotations), index));
index++;
} catch (ConfigurationException e) {
errors.merge(e.getErrorMessages());
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
}
errors.throwConfigurationExceptionIfErrorsExist();
return ImmutableList.copyOf(dependencies);
}
// This metohd is necessary to create a Dependency<T> with proper generic type information
private <T> Dependency<T> newDependency(Key<T> key, boolean allowsNull, int parameterIndex) {
return new Dependency<T>(this, key, allowsNull, parameterIndex);
}
/**
* Returns the injected constructor, field, or method.
*/
public Member getMember() {
// TODO: Don't expose the original member (which probably has setAccessible(true)).
return member;
}
/**
* Returns the dependencies for this injection point. If the injection point is for a method or
* constructor, the dependencies will correspond to that member's parameters. Field injection
* points always have a single dependency for the field itself.
*
* @return a possibly-empty list
*/
public List<Dependency<?>> getDependencies() {
return dependencies;
}
/**
* Returns true if this injection point shall be skipped if the injector cannot resolve bindings
* for all required dependencies. Both explicit bindings (as specified in a module), and implicit
* bindings ({@literal @}{@link com.google.inject.ImplementedBy ImplementedBy}, default
* constructors etc.) may be used to satisfy optional injection points.
*/
public boolean isOptional() {
return optional;
}
/**
* Returns true if the element is annotated with {@literal @}{@link Toolable}.
*
* @since 3.0
*/
public boolean isToolable() {
return ((AnnotatedElement)member).isAnnotationPresent(Toolable.class);
}
/**
* Returns the generic type that defines this injection point. If the member exists on a
* parameterized type, the result will include more type information than the member's {@link
* Member#getDeclaringClass() raw declaring class}.
*
* @since 3.0
*/
public TypeLiteral<?> getDeclaringType() {
return declaringType;
}
@Override public boolean equals(Object o) {
return o instanceof InjectionPoint
&& member.equals(((InjectionPoint) o).member)
&& declaringType.equals(((InjectionPoint) o).declaringType);
}
@Override public int hashCode() {
return member.hashCode() ^ declaringType.hashCode();
}
@Override public String toString() {
return Classes.toString(member);
}
/**
* Returns a new injection point for the specified constructor. If the declaring type of {@code
* constructor} is parameterized (such as {@code List<T>}), prefer the overload that includes a
* type literal.
*
* @param constructor any single constructor present on {@code type}.
*
* @since 3.0
*/
public static <T> InjectionPoint forConstructor(Constructor<T> constructor) {
return new InjectionPoint(TypeLiteral.get(constructor.getDeclaringClass()), constructor);
}
/**
* Returns a new injection point for the specified constructor of {@code type}.
*
* @param constructor any single constructor present on {@code type}.
* @param type the concrete type that defines {@code constructor}.
*
* @since 3.0
*/
public static <T> InjectionPoint forConstructor(
Constructor<T> constructor, TypeLiteral<? extends T> type) {
if (type.getRawType() != constructor.getDeclaringClass()) {
new Errors(type)
.constructorNotDefinedByType(constructor, type)
.throwConfigurationExceptionIfErrorsExist();
}
return new InjectionPoint(type, constructor);
}
/**
* Returns a new injection point for the injectable constructor of {@code type}.
*
* @param type a concrete type with exactly one constructor annotated {@literal @}{@link Inject},
* or a no-arguments constructor that is not private.
* @throws ConfigurationException if there is no injectable constructor, more than one injectable
* constructor, or if parameters of the injectable constructor are malformed, such as a
* parameter with multiple binding annotations.
*/
public static InjectionPoint forConstructorOf(TypeLiteral<?> type) {
Class<?> rawType = getRawType(type.getType());
Errors errors = new Errors(rawType);
Constructor<?> injectableConstructor = null;
for (Constructor<?> constructor : rawType.getDeclaredConstructors()) {
boolean optional;
Inject guiceInject = constructor.getAnnotation(Inject.class);
if (guiceInject == null) {
javax.inject.Inject javaxInject = constructor.getAnnotation(javax.inject.Inject.class);
if (javaxInject == null) {
continue;
}
optional = false;
} else {
optional = guiceInject.optional();
}
if (optional) {
errors.optionalConstructor(constructor);
}
if (injectableConstructor != null) {
errors.tooManyConstructors(rawType);
}
injectableConstructor = constructor;
checkForMisplacedBindingAnnotations(injectableConstructor, errors);
}
errors.throwConfigurationExceptionIfErrorsExist();
if (injectableConstructor != null) {
return new InjectionPoint(type, injectableConstructor);
}
// If no annotated constructor is found, look for a no-arg constructor instead.
try {
Constructor<?> noArgConstructor = rawType.getDeclaredConstructor();
// Disallow private constructors on non-private classes (unless they have @Inject)
if (Modifier.isPrivate(noArgConstructor.getModifiers())
&& !Modifier.isPrivate(rawType.getModifiers())) {
errors.missingConstructor(rawType);
throw new ConfigurationException(errors.getMessages());
}
checkForMisplacedBindingAnnotations(noArgConstructor, errors);
return new InjectionPoint(type, noArgConstructor);
} catch (NoSuchMethodException e) {
errors.missingConstructor(rawType);
throw new ConfigurationException(errors.getMessages());
}
}
/**
* Returns a new injection point for the injectable constructor of {@code type}.
*
* @param type a concrete type with exactly one constructor annotated {@literal @}{@link Inject},
* or a no-arguments constructor that is not private.
* @throws ConfigurationException if there is no injectable constructor, more than one injectable
* constructor, or if parameters of the injectable constructor are malformed, such as a
* parameter with multiple binding annotations.
*/
public static InjectionPoint forConstructorOf(Class<?> type) {
return forConstructorOf(TypeLiteral.get(type));
}
/**
* Returns all static method and field injection points on {@code type}.
*
* @return a possibly empty set of injection points. The set has a specified iteration order. All
* fields are returned and then all methods. Within the fields, supertype fields are returned
* before subtype fields. Similarly, supertype methods are returned before subtype methods.
* @throws ConfigurationException if there is a malformed injection point on {@code type}, such as
* a field with multiple binding annotations. The exception's {@link
* ConfigurationException#getPartialValue() partial value} is a {@code Set<InjectionPoint>}
* of the valid injection points.
*/
public static Set<InjectionPoint> forStaticMethodsAndFields(TypeLiteral<?> type) {
Errors errors = new Errors();
Set<InjectionPoint> result;
if (type.getRawType().isInterface()) {
errors.staticInjectionOnInterface(type.getRawType());
result = null;
} else {
result = getInjectionPoints(type, true, errors);
}
if (errors.hasErrors()) {
throw new ConfigurationException(errors.getMessages()).withPartialValue(result);
}
return result;
}
/**
* Returns all static method and field injection points on {@code type}.
*
* @return a possibly empty set of injection points. The set has a specified iteration order. All
* fields are returned and then all methods. Within the fields, supertype fields are returned
* before subtype fields. Similarly, supertype methods are returned before subtype methods.
* @throws ConfigurationException if there is a malformed injection point on {@code type}, such as
* a field with multiple binding annotations. The exception's {@link
* ConfigurationException#getPartialValue() partial value} is a {@code Set<InjectionPoint>}
* of the valid injection points.
*/
public static Set<InjectionPoint> forStaticMethodsAndFields(Class<?> type) {
return forStaticMethodsAndFields(TypeLiteral.get(type));
}
/**
* Returns all instance method and field injection points on {@code type}.
*
* @return a possibly empty set of injection points. The set has a specified iteration order. All
* fields are returned and then all methods. Within the fields, supertype fields are returned
* before subtype fields. Similarly, supertype methods are returned before subtype methods.
* @throws ConfigurationException if there is a malformed injection point on {@code type}, such as
* a field with multiple binding annotations. The exception's {@link
* ConfigurationException#getPartialValue() partial value} is a {@code Set<InjectionPoint>}
* of the valid injection points.
*/
public static Set<InjectionPoint> forInstanceMethodsAndFields(TypeLiteral<?> type) {
Errors errors = new Errors();
Set<InjectionPoint> result = getInjectionPoints(type, false, errors);
if (errors.hasErrors()) {
throw new ConfigurationException(errors.getMessages()).withPartialValue(result);
}
return result;
}
/**
* Returns all instance method and field injection points on {@code type}.
*
* @return a possibly empty set of injection points. The set has a specified iteration order. All
* fields are returned and then all methods. Within the fields, supertype fields are returned
* before subtype fields. Similarly, supertype methods are returned before subtype methods.
* @throws ConfigurationException if there is a malformed injection point on {@code type}, such as
* a field with multiple binding annotations. The exception's {@link
* ConfigurationException#getPartialValue() partial value} is a {@code Set<InjectionPoint>}
* of the valid injection points.
*/
public static Set<InjectionPoint> forInstanceMethodsAndFields(Class<?> type) {
return forInstanceMethodsAndFields(TypeLiteral.get(type));
}
/**
* Returns true if the binding annotation is in the wrong place.
*/
private static boolean checkForMisplacedBindingAnnotations(Member member, Errors errors) {
Annotation misplacedBindingAnnotation = Annotations.findBindingAnnotation(
errors, member, ((AnnotatedElement) member).getAnnotations());
if (misplacedBindingAnnotation == null) {
return false;
}
// don't warn about misplaced binding annotations on methods when there's a field with the same
// name. In Scala, fields always get accessor methods (that we need to ignore). See bug 242.
if (member instanceof Method) {
try {
if (member.getDeclaringClass().getDeclaredField(member.getName()) != null) {
return false;
}
} catch (NoSuchFieldException ignore) {
}
}
errors.misplacedBindingAnnotation(member, misplacedBindingAnnotation);
return true;
}
/**
* Node in the doubly-linked list of injectable members (fields and methods).
*/
static abstract class InjectableMember {
final TypeLiteral<?> declaringType;
final boolean optional;
final boolean jsr330;
InjectableMember previous;
InjectableMember next;
InjectableMember(TypeLiteral<?> declaringType, Annotation atInject) {
this.declaringType = declaringType;
if (atInject.annotationType() == javax.inject.Inject.class) {
optional = false;
jsr330 = true;
return;
}
jsr330 = false;
optional = ((Inject) atInject).optional();
}
abstract InjectionPoint toInjectionPoint();
}
static class InjectableField extends InjectableMember {
final Field field;
InjectableField(TypeLiteral<?> declaringType, Field field,
Annotation atInject) {
super(declaringType, atInject);
this.field = field;
}
@Override
InjectionPoint toInjectionPoint() {
return new InjectionPoint(declaringType, field, optional);
}
}
static class InjectableMethod extends InjectableMember {
final Method method;
/**
* true if this method overrode a method that was annotated
* with com.google.inject.Inject. used to allow different
* override behavior for guice inject vs javax.inject.Inject
*/
boolean overrodeGuiceInject;
InjectableMethod(TypeLiteral<?> declaringType, Method method,
Annotation atInject) {
super(declaringType, atInject);
this.method = method;
}
@Override
InjectionPoint toInjectionPoint() {
return new InjectionPoint(declaringType, method, optional);
}
public boolean isFinal() {
return Modifier.isFinal(method.getModifiers());
}
}
static Annotation getAtInject(AnnotatedElement member) {
Annotation a = member.getAnnotation(javax.inject.Inject.class);
return a == null ? member.getAnnotation(Inject.class) : a;
}
/**
* Linked list of injectable members.
*/
static class InjectableMembers {
InjectableMember head;
InjectableMember tail;
void add(InjectableMember member) {
if (head == null) {
head = tail = member;
} else {
member.previous = tail;
tail.next = member;
tail = member;
}
}
void remove(InjectableMember member) {
if (member.previous != null) {
member.previous.next = member.next;
}
if (member.next != null) {
member.next.previous = member.previous;
}
if (head == member) {
head = member.next;
}
if (tail == member) {
tail = member.previous;
}
}
boolean isEmpty() {
return head == null;
}
}
/** Position in type hierarchy. */
enum Position {
TOP, // No need to check for overridden methods
MIDDLE,
BOTTOM // Methods won't be overridden
}
/**
* Keeps track of injectable methods so we can remove methods that get overridden in O(1) time.
* Uses our position in the type hierarchy to perform optimizations.
*/
static class OverrideIndex {
final InjectableMembers injectableMembers;
Map<Signature, List<InjectableMethod>> bySignature;
Position position = Position.TOP;
OverrideIndex(InjectableMembers injectableMembers) {
this.injectableMembers = injectableMembers;
}
/* Caches the signature for the last method. */
Method lastMethod;
Signature lastSignature;
/**
* Removes a method overridden by the given method, if present. In order to
* remain backwards compatible with prior Guice versions, this will *not*
* remove overridden methods if 'alwaysRemove' is false and the overridden
* signature was annotated with a com.google.inject.Inject.
*
* @param method
* The method used to determine what is overridden and should be
* removed.
* @param alwaysRemove
* true if overridden methods should be removed even if they were
* guice @Inject
* @param injectableMethod
* if this method overrode any guice @Inject methods,
* {@link InjectableMethod#overrodeGuiceInject} is set to true
*/
boolean removeIfOverriddenBy(Method method, boolean alwaysRemove,
InjectableMethod injectableMethod) {
if (position == Position.TOP) {
// If we're at the top of the hierarchy, there's nothing to override.
return false;
}
if (bySignature == null) {
// We encountered a method in a subclass. Time to index the
// methods in the parent class.
bySignature = new HashMap<Signature, List<InjectableMethod>>();
for (InjectableMember member = injectableMembers.head; member != null;
member = member.next) {
if (!(member instanceof InjectableMethod)) continue;
InjectableMethod im = (InjectableMethod) member;
if (im.isFinal()) continue;
List<InjectableMethod> methods = new ArrayList<InjectableMethod>();
methods.add(im);
bySignature.put(new Signature(im.method), methods);
}
}
lastMethod = method;
Signature signature = lastSignature = new Signature(method);
List<InjectableMethod> methods = bySignature.get(signature);
boolean removed = false;
if (methods != null) {
for (Iterator<InjectableMethod> iterator = methods.iterator();
iterator.hasNext();) {
InjectableMethod possiblyOverridden = iterator.next();
if (overrides(method, possiblyOverridden.method)) {
boolean wasGuiceInject =
!possiblyOverridden.jsr330 || possiblyOverridden.overrodeGuiceInject;
if(injectableMethod != null) {
injectableMethod.overrodeGuiceInject = wasGuiceInject;
}
// Only actually remove the methods if we want to force
// remove or if the signature never specified @com.google.inject.Inject
// somewhere.
if(alwaysRemove || !wasGuiceInject) {
removed = true;
iterator.remove();
injectableMembers.remove(possiblyOverridden);
}
}
}
}
return removed;
}
/**
* Adds the given method to the list of injection points. Keeps track of it in this index
* in case it gets overridden.
*/
void add(InjectableMethod injectableMethod) {
injectableMembers.add(injectableMethod);
if (position == Position.BOTTOM
|| injectableMethod.isFinal()) {
// This method can't be overridden, so there's no need to index it.
return;
}
if (bySignature != null) {
// Try to reuse the signature we created during removal
Signature signature = injectableMethod.method == lastMethod
? lastSignature : new Signature(injectableMethod.method);
List<InjectableMethod> methods = bySignature.get(signature);
if (methods == null) {
methods = new ArrayList<InjectableMethod>();
bySignature.put(signature, methods);
}
methods.add(injectableMethod);
}
}
}
/**
* Returns an ordered, immutable set of injection points for the given type. Members in
* superclasses come before members in subclasses. Within a class, fields come before methods.
* Overridden methods are filtered out.
*
* @param statics true is this method should return static members, false for instance members
* @param errors used to record errors
*/
private static Set<InjectionPoint> getInjectionPoints(final TypeLiteral<?> type,
boolean statics, Errors errors) {
InjectableMembers injectableMembers = new InjectableMembers();
OverrideIndex overrideIndex = null;
List<TypeLiteral<?>> hierarchy = hierarchyFor(type);
int topIndex = hierarchy.size() - 1;
for (int i = topIndex; i >= 0; i--) {
if (overrideIndex != null && i < topIndex) {
// Knowing the position within the hierarchy helps us make optimizations.
if (i == 0) {
overrideIndex.position = Position.BOTTOM;
} else {
overrideIndex.position = Position.MIDDLE;
}
}
TypeLiteral<?> current = hierarchy.get(i);
for (Field field : current.getRawType().getDeclaredFields()) {
if (Modifier.isStatic(field.getModifiers()) == statics) {
Annotation atInject = getAtInject(field);
if (atInject != null) {
InjectableField injectableField = new InjectableField(current, field, atInject);
if (injectableField.jsr330 && Modifier.isFinal(field.getModifiers())) {
errors.cannotInjectFinalField(field);
}
injectableMembers.add(injectableField);
}
}
}
for (Method method : current.getRawType().getDeclaredMethods()) {
if (isEligibleForInjection(method, statics)) {
Annotation atInject = getAtInject(method);
if (atInject != null) {
InjectableMethod injectableMethod = new InjectableMethod(
current, method, atInject);
if (checkForMisplacedBindingAnnotations(method, errors)
|| !isValidMethod(injectableMethod, errors)) {
if (overrideIndex != null) {
boolean removed = overrideIndex.removeIfOverriddenBy(method, false, injectableMethod);
if(removed) {
logger.log(Level.WARNING, "Method: {0} is not a valid injectable method ("
+ "because it either has misplaced binding annotations "
+ "or specifies type parameters) but is overriding a method that is valid. "
+ "Because it is not valid, the method will not be injected. "
+ "To fix this, make the method a valid injectable method.", method);
}
}
continue;
}
if (statics) {
injectableMembers.add(injectableMethod);
} else {
if (overrideIndex == null) {
/*
* Creating the override index lazily means that the first type in the hierarchy
* with injectable methods (not necessarily the top most type) will be treated as
* the TOP position and will enjoy the same optimizations (no checks for overridden
* methods, etc.).
*/
overrideIndex = new OverrideIndex(injectableMembers);
} else {
// Forcibly remove the overriden method, otherwise we'll inject
// it twice.
overrideIndex.removeIfOverriddenBy(method, true, injectableMethod);
}
overrideIndex.add(injectableMethod);
}
} else {
if(overrideIndex != null) {
boolean removed = overrideIndex.removeIfOverriddenBy(method, false, null);
if(removed) {
logger.log(Level.WARNING, "Method: {0} is not annotated with @Inject but "
+ "is overriding a method that is annotated with @javax.inject.Inject. Because "
+ "it is not annotated with @Inject, the method will not be injected. "
+ "To fix this, annotate the method with @Inject.", method);
}
}
}
}
}
}
if (injectableMembers.isEmpty()) {
return Collections.emptySet();
}
ImmutableSet.Builder<InjectionPoint> builder = ImmutableSet.builder();
for (InjectableMember im = injectableMembers.head; im != null;
im = im.next) {
try {
builder.add(im.toInjectionPoint());
} catch (ConfigurationException ignorable) {
if (!im.optional) {
errors.merge(ignorable.getErrorMessages());
}
}
}
return builder.build();
}
/**
* Returns true if the method is eligible to be injected. This is different than
* {@link #isValidMethod}, because ineligibility will not drop a method
* from being injected if a superclass was eligible & valid.
* Bridge & synthetic methods are excluded from eligibility for two reasons:
*
* <p>Prior to Java8, javac would generate these methods in subclasses without
* annotations, which means this would accidentally stop injecting a method
* annotated with {@link javax.inject.Inject}, since the spec says to stop
* injecting if a subclass isn't annotated with it.
*
* <p>Starting at Java8, javac copies the annotations to the generated subclass
* method, except it leaves out the generic types. If this considered it a valid
* injectable method, this would eject the parent's overridden method that had the
* proper generic types, and would use invalid injectable parameters as a result.
*
* <p>The fix for both is simply to ignore these synthetic bridge methods.
*/
private static boolean isEligibleForInjection(Method method, boolean statics) {
return Modifier.isStatic(method.getModifiers()) == statics
&& !method.isBridge()
&& !method.isSynthetic();
}
private static boolean isValidMethod(InjectableMethod injectableMethod,
Errors errors) {
boolean result = true;
if (injectableMethod.jsr330) {
Method method = injectableMethod.method;
if (Modifier.isAbstract(method.getModifiers())) {
errors.cannotInjectAbstractMethod(method);
result = false;
}
if (method.getTypeParameters().length > 0) {
errors.cannotInjectMethodWithTypeParameters(method);
result = false;
}
}
return result;
}
private static List<TypeLiteral<?>> hierarchyFor(TypeLiteral<?> type) {
List<TypeLiteral<?>> hierarchy = new ArrayList<TypeLiteral<?>>();
TypeLiteral<?> current = type;
while (current.getRawType() != Object.class) {
hierarchy.add(current);
current = current.getSupertype(current.getRawType().getSuperclass());
}
return hierarchy;
}
/**
* Returns true if a overrides b. Assumes signatures of a and b are the same and a's declaring
* class is a subclass of b's declaring class.
*/
private static boolean overrides(Method a, Method b) {
// See JLS section 8.4.8.1
int modifiers = b.getModifiers();
if (Modifier.isPublic(modifiers) || Modifier.isProtected(modifiers)) {
return true;
}
if (Modifier.isPrivate(modifiers)) {
return false;
}
// b must be package-private
return a.getDeclaringClass().getPackage().equals(b.getDeclaringClass().getPackage());
}
/**
* A method signature. Used to handle method overridding.
*/
static class Signature {
final String name;
final Class[] parameterTypes;
final int hash;
Signature(Method method) {
this.name = method.getName();
this.parameterTypes = method.getParameterTypes();
int h = name.hashCode();
h = h * 31 + parameterTypes.length;
for (Class parameterType : parameterTypes) {
h = h * 31 + parameterType.hashCode();
}
this.hash = h;
}
@Override public int hashCode() {
return this.hash;
}
@Override public boolean equals(Object o) {
if (!(o instanceof Signature)) {
return false;
}
Signature other = (Signature) o;
if (!name.equals(other.name)) {
return false;
}
if (parameterTypes.length != other.parameterTypes.length) {
return false;
}
for (int i = 0; i < parameterTypes.length; i++) {
if (parameterTypes[i] != other.parameterTypes[i]) {
return false;
}
}
return true;
}
}
}