com.google.inject.internal.Annotations Maven / Gradle / Ivy
/*
* Copyright (C) 2006 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.internal;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import com.google.common.base.Joiner;
import com.google.common.base.Joiner.MapJoiner;
import com.google.common.base.Preconditions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.inject.BindingAnnotation;
import com.google.inject.Key;
import com.google.inject.ScopeAnnotation;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.util.Classes;
import com.google.inject.name.Named;
import com.google.inject.name.Names;
import java.lang.annotation.Annotation;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Collection;
import java.util.Map;
/**
* Annotation utilities.
*
* @author [email protected] (Bob Lee)
*/
public class Annotations {
/** Returns {@code true} if the given annotation type has no attributes. */
public static boolean isMarker(Class annotationType) {
return annotationType.getDeclaredMethods().length == 0;
}
public static boolean isAllDefaultMethods(Class annotationType) {
boolean hasMethods = false;
for (Method m : annotationType.getDeclaredMethods()) {
hasMethods = true;
if (m.getDefaultValue() == null) {
return false;
}
}
return hasMethods;
}
private static final LoadingCache, Annotation> cache =
CacheBuilder.newBuilder()
.weakKeys()
.build(
new CacheLoader, Annotation>() {
@Override
public Annotation load(Class input) {
return generateAnnotationImpl(input);
}
});
/**
* Generates an Annotation for the annotation class. Requires that the annotation is all
* optionals.
*/
@SuppressWarnings("unchecked") // Safe because generateAnnotationImpl returns T for Class
public static T generateAnnotation(Class annotationType) {
Preconditions.checkState(
isAllDefaultMethods(annotationType), "%s is not all default methods", annotationType);
return (T) cache.getUnchecked(annotationType);
}
private static T generateAnnotationImpl(final Class annotationType) {
final Map members = resolveMembers(annotationType);
return annotationType.cast(
Proxy.newProxyInstance(
annotationType.getClassLoader(),
new Class[] {annotationType},
new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Exception {
String name = method.getName();
if (name.equals("annotationType")) {
return annotationType;
} else if (name.equals("toString")) {
return annotationToString(annotationType, members);
} else if (name.equals("hashCode")) {
return annotationHashCode(annotationType, members);
} else if (name.equals("equals")) {
return annotationEquals(annotationType, members, args[0]);
} else {
return members.get(name);
}
}
}));
}
private static ImmutableMap resolveMembers(
Class annotationType) {
ImmutableMap.Builder result = ImmutableMap.builder();
for (Method method : annotationType.getDeclaredMethods()) {
result.put(method.getName(), method.getDefaultValue());
}
return result.buildOrThrow();
}
/** Implements {@link Annotation#equals}. */
private static boolean annotationEquals(
Class type, Map members, Object other)
throws Exception {
if (!type.isInstance(other)) {
return false;
}
for (Method method : type.getDeclaredMethods()) {
String name = method.getName();
if (!Arrays.deepEquals(
new Object[] {method.invoke(other)}, new Object[] {members.get(name)})) {
return false;
}
}
return true;
}
/** Implements {@link Annotation#hashCode}. */
private static int annotationHashCode(
Class type, Map members) throws Exception {
int result = 0;
for (Method method : type.getDeclaredMethods()) {
String name = method.getName();
Object value = members.get(name);
result += (127 * name.hashCode()) ^ (Arrays.deepHashCode(new Object[] {value}) - 31);
}
return result;
}
private static final MapJoiner JOINER = Joiner.on(", ").withKeyValueSeparator("=");
/** Implements {@link Annotation#toString}. */
private static String annotationToString(
Class type, Map members) throws Exception {
StringBuilder sb = new StringBuilder().append('@').append(type.getName()).append('(');
JOINER.appendTo(
sb,
Maps.transformValues(
members,
arg -> {
String s = Arrays.deepToString(new Object[] {arg});
return s.substring(1, s.length() - 1); // cut off brackets
}));
return sb.append(')').toString();
}
/** Returns true if the given annotation is retained at runtime. */
public static boolean isRetainedAtRuntime(Class annotationType) {
Retention retention = annotationType.getAnnotation(Retention.class);
return retention != null && retention.value() == RetentionPolicy.RUNTIME;
}
/** Returns the scope annotation on {@code type}, or null if none is specified. */
public static Class findScopeAnnotation(
Errors errors, Class implementation) {
return findScopeAnnotation(errors, implementation.getAnnotations());
}
/** Returns the scoping annotation, or null if there isn't one. */
public static Class findScopeAnnotation(
Errors errors, Annotation[] annotations) {
Class found = null;
for (Annotation annotation : annotations) {
Class annotationType = annotation.annotationType();
if (isScopeAnnotation(annotationType)) {
if (found != null) {
errors.duplicateScopeAnnotations(found, annotationType);
} else {
found = annotationType;
}
}
}
return found;
}
static boolean containsComponentAnnotation(Annotation[] annotations) {
for (Annotation annotation : annotations) {
// TODO(user): Should we scope this down to dagger.Component?
if (annotation.annotationType().getSimpleName().equals("Component")) {
return true;
}
}
return false;
}
private static class AnnotationToStringConfig {
final boolean quote;
final boolean includeMemberName;
final boolean dollarSeparator;
AnnotationToStringConfig(boolean quote, boolean includeMemberName, boolean dollarSeparator) {
this.quote = quote;
this.includeMemberName = includeMemberName;
this.dollarSeparator = dollarSeparator;
}
}
private static final AnnotationToStringConfig ANNOTATION_TO_STRING_CONFIG =
determineAnnotationToStringConfig();
/**
* Returns {@code value}, quoted if annotation implementations quote their member values. In Java
* 9, annotations quote their string members.
*/
public static String memberValueString(String value) {
return ANNOTATION_TO_STRING_CONFIG.quote ? "\"" + value + "\"" : value;
}
/**
* Returns string representation of the annotation memeber.
*
* The value of the member is prefixed with `memberName=` unless the runtime omits the member
* name. The value of the member is quoted if annotation implementations quote their member values
* and the value type is String.
*
*
In Java 9, annotations quote their string members and in Java 15, the member name is
* omitted.
*/
public static String memberValueString(String memberName, Object value) {
StringBuilder sb = new StringBuilder();
boolean quote = ANNOTATION_TO_STRING_CONFIG.quote;
boolean includeMemberName = ANNOTATION_TO_STRING_CONFIG.includeMemberName;
if (includeMemberName) {
sb.append(memberName).append('=');
}
if (quote && (value instanceof String)) {
sb.append('"').append(value).append('"');
} else {
sb.append(value);
}
return sb.toString();
}
/**
* Returns the string representation of the annotation class as it would appear in an annotation
* instance's toString() method.
*
*
In earlier JDKs, the string representation mirrored Class.getName() (which uses $ to
* separate outer and inner classes), but newer JDKs use . as the separator).
*/
public static String annotationInstanceClassString(
Class ann, boolean includePackage) {
if (ANNOTATION_TO_STRING_CONFIG.dollarSeparator) {
if (includePackage || ann.getPackage() == null) {
return "@" + ann.getName();
}
return "@" + ann.getName().substring(ann.getPackage().getName().length() + 1);
}
return "@" + dotSeparatedParentOrPackage(ann, includePackage);
}
private static String dotSeparatedParentOrPackage(Class ann, boolean includePackage) {
if (ann.getDeclaringClass() == null) {
if (includePackage) {
return ann.getPackage().getName() + "." + ann.getSimpleName();
}
return ann.getSimpleName();
}
return dotSeparatedParentOrPackage(ann.getDeclaringClass(), includePackage)
+ "."
+ ann.getSimpleName();
}
@Retention(RUNTIME)
private @interface TestAnnotation {
String value();
}
@TestAnnotation("determineAnnotationToStringConfig")
private static AnnotationToStringConfig determineAnnotationToStringConfig() {
try {
String annotation =
Annotations.class
.getDeclaredMethod("determineAnnotationToStringConfig")
.getAnnotation(TestAnnotation.class)
.toString();
boolean quote = annotation.contains("\"determineAnnotationToStringConfig\"");
boolean includeMemberName = annotation.contains("value=");
boolean dollarSeparator = annotation.contains("Annotations$TestAnnotation");
return new AnnotationToStringConfig(quote, includeMemberName, dollarSeparator);
} catch (NoSuchMethodException e) {
throw new AssertionError(e);
}
}
/** Checks for the presence of annotations. Caches results because Android doesn't. */
static class AnnotationChecker {
private final Collection> annotationTypes;
/** Returns true if the given class has one of the desired annotations. */
private CacheLoader, Boolean> hasAnnotations =
new CacheLoader, Boolean>() {
@Override
public Boolean load(Class annotationType) {
for (Annotation annotation : annotationType.getAnnotations()) {
if (annotationTypes.contains(annotation.annotationType())) {
return true;
}
}
return false;
}
};
final LoadingCache, Boolean> cache =
CacheBuilder.newBuilder().weakKeys().build(hasAnnotations);
/** Constructs a new checker that looks for annotations of the given types. */
AnnotationChecker(Collection> annotationTypes) {
this.annotationTypes = annotationTypes;
}
/** Returns true if the given type has one of the desired annotations. */
boolean hasAnnotations(Class annotated) {
return cache.getUnchecked(annotated);
}
}
private static final AnnotationChecker scopeChecker =
new AnnotationChecker(
Arrays.asList(
ScopeAnnotation.class,
jakarta.inject.Scope.class));
public static boolean isScopeAnnotation(Class annotationType) {
return scopeChecker.hasAnnotations(annotationType);
}
/**
* Adds an error if there is a misplaced annotations on {@code type}. Scoping annotations are not
* allowed on abstract classes or interfaces.
*/
public static void checkForMisplacedScopeAnnotations(
Class type, Object source, Errors errors) {
if (Classes.isConcrete(type)) {
return;
}
Class scopeAnnotation = findScopeAnnotation(errors, type);
if (scopeAnnotation != null
// We let Dagger Components through to aid migrations.
&& !containsComponentAnnotation(type.getAnnotations())) {
errors.withSource(type).scopeAnnotationOnAbstractType(scopeAnnotation, type, source);
}
}
// NOTE: getKey/findBindingAnnotation are used by Gin which is abandoned. So changing this API
// will prevent Gin users from upgrading Guice version.
/** Gets a key for the given type, member and annotations. */
public static Key getKey(
TypeLiteral type, Member member, Annotation[] annotations, Errors errors)
throws ErrorsException {
int numErrorsBefore = errors.size();
Annotation found = findBindingAnnotation(errors, member, annotations);
errors.throwIfNewErrors(numErrorsBefore);
return found == null ? Key.get(type) : Key.get(type, found);
}
/** Returns the binding annotation on {@code member}, or null if there isn't one. */
public static Annotation findBindingAnnotation(
Errors errors, Member member, Annotation[] annotations) {
Annotation found = null;
for (Annotation annotation : annotations) {
Class annotationType = annotation.annotationType();
if (isBindingAnnotation(annotationType)) {
if (found != null) {
errors.duplicateBindingAnnotations(member, found.annotationType(), annotationType);
} else {
found = annotation;
}
}
}
return found;
}
private static final AnnotationChecker bindingAnnotationChecker =
new AnnotationChecker(
Arrays.asList(
BindingAnnotation.class,
jakarta.inject.Qualifier.class));
/** Returns true if annotations of the specified type are binding annotations. */
public static boolean isBindingAnnotation(Class annotationType) {
return bindingAnnotationChecker.hasAnnotations(annotationType);
}
/**
* If the annotation is an instance of {@code jakarta.inject.Named}, canonicalizes to
* com.google.guice.name.Named. Returns the given annotation otherwise.
*/
public static Annotation canonicalizeIfNamed(Annotation annotation) {
if (annotation instanceof jakarta.inject.Named) {
return Names.named(((jakarta.inject.Named) annotation).value());
}
return annotation;
}
/**
* If the annotation is the class {@code jakarta.inject.Named}, canonicalizes to
* com.google.guice.name.Named. Returns the given annotation class otherwise.
*/
public static Class canonicalizeIfNamed(
Class annotationType) {
if (
annotationType == jakarta.inject.Named.class) {
return Named.class;
}
return annotationType;
}
/**
* Returns the name the binding should use. This is based on the annotation. If the annotation has
* an instance and is not a marker annotation, we ask the annotation for its toString. If it was a
* marker annotation or just an annotation type, we use the annotation's name. Otherwise, the name
* is the empty string.
*/
public static String nameOf(Key key) {
Annotation annotation = key.getAnnotation();
Class annotationType = key.getAnnotationType();
if (annotation != null && !isMarker(annotationType)) {
return key.getAnnotation().toString();
} else if (key.getAnnotationType() != null) {
return '@' + key.getAnnotationType().getName();
} else {
return "";
}
}
}