org.springframework.core.annotation.AnnotationTypeMapping Maven / Gradle / Ivy
/*
* Copyright 2002-2019 the original author or authors.
*
* 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
*
* https://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 org.springframework.core.annotation;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BiFunction;
import org.springframework.core.annotation.AnnotationTypeMapping.MirrorSets.MirrorSet;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
/**
* Provides mapping information for a single annotation (or meta-annotation) in
* the context of a root annotation type.
*
* @author Phillip Webb
* @author Sam Brannen
* @since 5.2
* @see AnnotationTypeMappings
*/
final class AnnotationTypeMapping {
private static final MirrorSet[] EMPTY_MIRROR_SETS = new MirrorSet[0];
@Nullable
private final AnnotationTypeMapping source;
private final AnnotationTypeMapping root;
private final int distance;
private final Class annotationType;
private final List> metaTypes;
@Nullable
private final Annotation annotation;
private final AttributeMethods attributes;
private final MirrorSets mirrorSets;
private final int[] aliasMappings;
private final int[] conventionMappings;
private final int[] annotationValueMappings;
private final AnnotationTypeMapping[] annotationValueSource;
private final Map> aliasedBy;
private final Set claimedAliases = new HashSet<>();
AnnotationTypeMapping(@Nullable AnnotationTypeMapping source,
Class annotationType, @Nullable Annotation annotation) {
this.source = source;
this.root = (source != null ? source.getRoot() : this);
this.distance = (source == null ? 0 : source.getDistance() + 1);
this.annotationType = annotationType;
this.metaTypes = merge(
source != null ? source.getMetaTypes() : null,
annotationType);
this.annotation = annotation;
this.attributes = AttributeMethods.forAnnotationType(annotationType);
this.mirrorSets = new MirrorSets();
this.aliasMappings = filledIntArray(this.attributes.size());
this.conventionMappings = filledIntArray(this.attributes.size());
this.annotationValueMappings = filledIntArray(this.attributes.size());
this.annotationValueSource = new AnnotationTypeMapping[this.attributes.size()];
this.aliasedBy = resolveAliasedForTargets();
processAliases();
addConventionMappings();
addConventionAnnotationValues();
}
private static List merge(@Nullable List existing, T element) {
if (existing == null) {
return Collections.singletonList(element);
}
List merged = new ArrayList<>(existing.size() + 1);
merged.addAll(existing);
merged.add(element);
return Collections.unmodifiableList(merged);
}
private Map> resolveAliasedForTargets() {
Map> aliasedBy = new HashMap<>();
for (int i = 0; i < this.attributes.size(); i++) {
Method attribute = this.attributes.get(i);
AliasFor aliasFor = AnnotationsScanner.getDeclaredAnnotation(attribute, AliasFor.class);
if (aliasFor != null) {
Method target = resolveAliasTarget(attribute, aliasFor);
aliasedBy.computeIfAbsent(target, key -> new ArrayList<>()).add(attribute);
}
}
return Collections.unmodifiableMap(aliasedBy);
}
private Method resolveAliasTarget(Method attribute, AliasFor aliasFor) {
return resolveAliasTarget(attribute, aliasFor, true);
}
private Method resolveAliasTarget(Method attribute, AliasFor aliasFor, boolean checkAliasPair) {
if (StringUtils.hasText(aliasFor.value()) && StringUtils.hasText(aliasFor.attribute())) {
throw new AnnotationConfigurationException(String.format(
"In @AliasFor declared on %s, attribute 'attribute' and its alias 'value' " +
"are present with values of '%s' and '%s', but only one is permitted.",
AttributeMethods.describe(attribute), aliasFor.attribute(),
aliasFor.value()));
}
Class targetAnnotation = aliasFor.annotation();
if (targetAnnotation == Annotation.class) {
targetAnnotation = this.annotationType;
}
String targetAttributeName = aliasFor.attribute();
if (!StringUtils.hasLength(targetAttributeName)) {
targetAttributeName = aliasFor.value();
}
if (!StringUtils.hasLength(targetAttributeName)) {
targetAttributeName = attribute.getName();
}
Method target = AttributeMethods.forAnnotationType(targetAnnotation).get(targetAttributeName);
if (target == null) {
if (targetAnnotation == this.annotationType) {
throw new AnnotationConfigurationException(String.format(
"@AliasFor declaration on %s declares an alias for '%s' which is not present.",
AttributeMethods.describe(attribute), targetAttributeName));
}
throw new AnnotationConfigurationException(String.format(
"%s is declared as an @AliasFor nonexistent %s.",
StringUtils.capitalize(AttributeMethods.describe(attribute)),
AttributeMethods.describe(targetAnnotation, targetAttributeName)));
}
if (target.equals(attribute)) {
throw new AnnotationConfigurationException(String.format(
"@AliasFor declaration on %s points to itself. " +
"Specify 'annotation' to point to a same-named attribute on a meta-annotation.",
AttributeMethods.describe(attribute)));
}
if (!isCompatibleReturnType(attribute.getReturnType(), target.getReturnType())) {
throw new AnnotationConfigurationException(String.format(
"Misconfigured aliases: %s and %s must declare the same return type.",
AttributeMethods.describe(attribute),
AttributeMethods.describe(target)));
}
if (isAliasPair(target) && checkAliasPair) {
AliasFor targetAliasFor = target.getAnnotation(AliasFor.class);
if (targetAliasFor != null) {
Method mirror = resolveAliasTarget(target, targetAliasFor, false);
if (!mirror.equals(attribute)) {
throw new AnnotationConfigurationException(String.format(
"%s must be declared as an @AliasFor %s, not %s.",
StringUtils.capitalize(AttributeMethods.describe(target)),
AttributeMethods.describe(attribute), AttributeMethods.describe(mirror)));
}
}
}
return target;
}
private boolean isAliasPair(Method target) {
return (this.annotationType == target.getDeclaringClass());
}
private boolean isCompatibleReturnType(Class attributeType, Class targetType) {
return (attributeType == targetType || attributeType == targetType.getComponentType());
}
private void processAliases() {
List aliases = new ArrayList<>();
for (int i = 0; i < this.attributes.size(); i++) {
aliases.clear();
aliases.add(this.attributes.get(i));
collectAliases(aliases);
if (aliases.size() > 1) {
processAliases(i, aliases);
}
}
}
private void collectAliases(List aliases) {
AnnotationTypeMapping mapping = this;
while (mapping != null) {
int size = aliases.size();
for (int j = 0; j < size; j++) {
List additional = mapping.aliasedBy.get(aliases.get(j));
if (additional != null) {
aliases.addAll(additional);
}
}
mapping = mapping.source;
}
}
private void processAliases(int attributeIndex, List aliases) {
int rootAttributeIndex = getFirstRootAttributeIndex(aliases);
AnnotationTypeMapping mapping = this;
while (mapping != null) {
if (rootAttributeIndex != -1 && mapping != this.root) {
for (int i = 0; i < mapping.attributes.size(); i++) {
if (aliases.contains(mapping.attributes.get(i))) {
mapping.aliasMappings[i] = rootAttributeIndex;
}
}
}
mapping.mirrorSets.updateFrom(aliases);
mapping.claimedAliases.addAll(aliases);
if (mapping.annotation != null) {
int[] resolvedMirrors = mapping.mirrorSets.resolve(null,
mapping.annotation, ReflectionUtils::invokeMethod);
for (int i = 0; i < mapping.attributes.size(); i++) {
if (aliases.contains(mapping.attributes.get(i))) {
this.annotationValueMappings[attributeIndex] = resolvedMirrors[i];
this.annotationValueSource[attributeIndex] = mapping;
}
}
}
mapping = mapping.source;
}
}
private int getFirstRootAttributeIndex(Collection aliases) {
AttributeMethods rootAttributes = this.root.getAttributes();
for (int i = 0; i < rootAttributes.size(); i++) {
if (aliases.contains(rootAttributes.get(i))) {
return i;
}
}
return -1;
}
private void addConventionMappings() {
if (this.distance == 0) {
return;
}
AttributeMethods rootAttributes = this.root.getAttributes();
int[] mappings = this.conventionMappings;
for (int i = 0; i < mappings.length; i++) {
String name = this.attributes.get(i).getName();
MirrorSet mirrors = getMirrorSets().getAssigned(i);
int mapped = rootAttributes.indexOf(name);
if (!MergedAnnotation.VALUE.equals(name) && mapped != -1) {
mappings[i] = mapped;
if (mirrors != null) {
for (int j = 0; j < mirrors.size(); j++) {
mappings[mirrors.getAttributeIndex(j)] = mapped;
}
}
}
}
}
private void addConventionAnnotationValues() {
for (int i = 0; i < this.attributes.size(); i++) {
Method attribute = this.attributes.get(i);
boolean isValueAttribute = MergedAnnotation.VALUE.equals(attribute.getName());
AnnotationTypeMapping mapping = this;
while (mapping != null && mapping.distance > 0) {
int mapped = mapping.getAttributes().indexOf(attribute.getName());
if (mapped != -1 && isBetterConventionAnnotationValue(i, isValueAttribute, mapping)) {
this.annotationValueMappings[i] = mapped;
this.annotationValueSource[i] = mapping;
}
mapping = mapping.source;
}
}
}
private boolean isBetterConventionAnnotationValue(int index, boolean isValueAttribute,
AnnotationTypeMapping mapping) {
if (this.annotationValueMappings[index] == -1) {
return true;
}
int existingDistance = this.annotationValueSource[index].distance;
return !isValueAttribute && existingDistance > mapping.distance;
}
/**
* Method called after all mappings have been set. At this point no further
* lookups from child mappings will occur.
*/
void afterAllMappingsSet() {
validateAllAliasesClaimed();
for (int i = 0; i < this.mirrorSets.size(); i++) {
validateMirrorSet(this.mirrorSets.get(i));
}
this.claimedAliases.clear();
}
private void validateAllAliasesClaimed() {
for (int i = 0; i < this.attributes.size(); i++) {
Method attribute = this.attributes.get(i);
AliasFor aliasFor = AnnotationsScanner.getDeclaredAnnotation(attribute, AliasFor.class);
if (aliasFor != null && !this.claimedAliases.contains(attribute)) {
Method target = resolveAliasTarget(attribute, aliasFor);
throw new AnnotationConfigurationException(String.format(
"@AliasFor declaration on %s declares an alias for %s which is not meta-present.",
AttributeMethods.describe(attribute), AttributeMethods.describe(target)));
}
}
}
private void validateMirrorSet(MirrorSet mirrorSet) {
Method firstAttribute = mirrorSet.get(0);
Object firstDefaultValue = firstAttribute.getDefaultValue();
for (int i = 1; i <= mirrorSet.size() - 1; i++) {
Method mirrorAttribute = mirrorSet.get(i);
Object mirrorDefaultValue = mirrorAttribute.getDefaultValue();
if (firstDefaultValue == null || mirrorDefaultValue == null) {
throw new AnnotationConfigurationException(String.format(
"Misconfigured aliases: %s and %s must declare default values.",
AttributeMethods.describe(firstAttribute), AttributeMethods.describe(mirrorAttribute)));
}
if (!ObjectUtils.nullSafeEquals(firstDefaultValue, mirrorDefaultValue)) {
throw new AnnotationConfigurationException(String.format(
"Misconfigured aliases: %s and %s must declare the same default value.",
AttributeMethods.describe(firstAttribute), AttributeMethods.describe(mirrorAttribute)));
}
}
}
/**
* Get the root mapping.
* @return the root mapping
*/
AnnotationTypeMapping getRoot() {
return this.root;
}
/**
* Get the source of the mapping or {@code null}.
* @return the source of the mapping
*/
@Nullable
AnnotationTypeMapping getSource() {
return this.source;
}
/**
* Get the distance of this mapping.
* @return the distance of the mapping
*/
int getDistance() {
return this.distance;
}
/**
* Get the type of the mapped annotation.
* @return the annotation type
*/
Class getAnnotationType() {
return this.annotationType;
}
List> getMetaTypes() {
return this.metaTypes;
}
/**
* Get the source annotation for this mapping. This will be the
* meta-annotation, or {@code null} if this is the root mapping.
* @return the source annotation of the mapping
*/
@Nullable
Annotation getAnnotation() {
return this.annotation;
}
/**
* Get the annotation attributes for the mapping annotation type.
* @return the attribute methods
*/
AttributeMethods getAttributes() {
return this.attributes;
}
/**
* Get the related index of an alias mapped attribute, or {@code -1} if
* there is no mapping. The resulting value is the index of the attribute on
* the root annotation that can be invoked in order to obtain the actual
* value.
* @param attributeIndex the attribute index of the source attribute
* @return the mapped attribute index or {@code -1}
*/
int getAliasMapping(int attributeIndex) {
return this.aliasMappings[attributeIndex];
}
/**
* Get the related index of a convention mapped attribute, or {@code -1}
* if there is no mapping. The resulting value is the index of the attribute
* on the root annotation that can be invoked in order to obtain the actual
* value.
* @param attributeIndex the attribute index of the source attribute
* @return the mapped attribute index or {@code -1}
*/
int getConventionMapping(int attributeIndex) {
return this.conventionMappings[attributeIndex];
}
/**
* Get a mapped attribute value from the most suitable
* {@link #getAnnotation() meta-annotation}.
* The resulting value is obtained from the closest meta-annotation,
* taking into consideration both convention and alias based mapping rules.
* For root mappings, this method will always return {@code null}.
* @param attributeIndex the attribute index of the source attribute
* @param metaAnnotationsOnly if only meta annotations should be considered.
* If this parameter is {@code false} then aliases within the annotation will
* also be considered.
* @return the mapped annotation value, or {@code null}
*/
@Nullable
Object getMappedAnnotationValue(int attributeIndex, boolean metaAnnotationsOnly) {
int mappedIndex = this.annotationValueMappings[attributeIndex];
if (mappedIndex == -1) {
return null;
}
AnnotationTypeMapping source = this.annotationValueSource[attributeIndex];
if (source == this && metaAnnotationsOnly) {
return null;
}
return ReflectionUtils.invokeMethod(source.attributes.get(mappedIndex), source.annotation);
}
/**
* Determine if the specified value is equivalent to the default value of the
* attribute at the given index.
* @param attributeIndex the attribute index of the source attribute
* @param value the value to check
* @param valueExtractor the value extractor used to extract values from any
* nested annotations
* @return {@code true} if the value is equivalent to the default value
*/
boolean isEquivalentToDefaultValue(int attributeIndex, Object value,
BiFunction valueExtractor) {
Method attribute = this.attributes.get(attributeIndex);
return isEquivalentToDefaultValue(attribute, value, valueExtractor);
}
/**
* Get the mirror sets for this type mapping.
* @return the attribute mirror sets
*/
MirrorSets getMirrorSets() {
return this.mirrorSets;
}
private static int[] filledIntArray(int size) {
int[] array = new int[size];
Arrays.fill(array, -1);
return array;
}
private static boolean isEquivalentToDefaultValue(Method attribute, Object value,
BiFunction valueExtractor) {
return areEquivalent(attribute.getDefaultValue(), value, valueExtractor);
}
private static boolean areEquivalent(@Nullable Object value, @Nullable Object extractedValue,
BiFunction valueExtractor) {
if (ObjectUtils.nullSafeEquals(value, extractedValue)) {
return true;
}
if (value instanceof Class && extractedValue instanceof String) {
return areEquivalent((Class) value, (String) extractedValue);
}
if (value instanceof Class[] && extractedValue instanceof String[]) {
return areEquivalent((Class[]) value, (String[]) extractedValue);
}
if (value instanceof Annotation) {
return areEquivalent((Annotation) value, extractedValue, valueExtractor);
}
return false;
}
private static boolean areEquivalent(Class[] value, String[] extractedValue) {
if (value.length != extractedValue.length) {
return false;
}
for (int i = 0; i < value.length; i++) {
if (!areEquivalent(value[i], extractedValue[i])) {
return false;
}
}
return true;
}
private static boolean areEquivalent(Class value, String extractedValue) {
return value.getName().equals(extractedValue);
}
private static boolean areEquivalent(Annotation annotation, @Nullable Object extractedValue,
BiFunction valueExtractor) {
AttributeMethods attributes = AttributeMethods.forAnnotationType(annotation.annotationType());
for (int i = 0; i < attributes.size(); i++) {
Method attribute = attributes.get(i);
if (!areEquivalent(ReflectionUtils.invokeMethod(attribute, annotation),
valueExtractor.apply(attribute, extractedValue), valueExtractor)) {
return false;
}
}
return true;
}
/**
* A collection of {@link MirrorSet} instances that provides details of all
* defined mirrors.
*/
class MirrorSets {
private MirrorSet[] mirrorSets;
private final MirrorSet[] assigned;
MirrorSets() {
this.assigned = new MirrorSet[attributes.size()];
this.mirrorSets = EMPTY_MIRROR_SETS;
}
void updateFrom(Collection aliases) {
MirrorSet mirrorSet = null;
int size = 0;
int last = -1;
for (int i = 0; i < attributes.size(); i++) {
Method attribute = attributes.get(i);
if (aliases.contains(attribute)) {
size++;
if (size > 1) {
if (mirrorSet == null) {
mirrorSet = new MirrorSet();
this.assigned[last] = mirrorSet;
}
this.assigned[i] = mirrorSet;
}
last = i;
}
}
if (mirrorSet != null) {
mirrorSet.update();
Set unique = new LinkedHashSet<>(Arrays.asList(this.assigned));
unique.remove(null);
this.mirrorSets = unique.toArray(EMPTY_MIRROR_SETS);
}
}
int size() {
return this.mirrorSets.length;
}
MirrorSet get(int index) {
return this.mirrorSets[index];
}
@Nullable
MirrorSet getAssigned(int attributeIndex) {
return this.assigned[attributeIndex];
}
int[] resolve(@Nullable Object source, @Nullable Object annotation,
BiFunction valueExtractor) {
int[] result = new int[attributes.size()];
for (int i = 0; i < result.length; i++) {
result[i] = i;
}
for (int i = 0; i < size(); i++) {
MirrorSet mirrorSet = get(i);
int resolved = mirrorSet.resolve(source, annotation, valueExtractor);
for (int j = 0; j < mirrorSet.size; j++) {
result[mirrorSet.indexes[j]] = resolved;
}
}
return result;
}
/**
* A single set of mirror attributes.
*/
class MirrorSet {
private int size;
private final int[] indexes = new int[attributes.size()];
void update() {
this.size = 0;
Arrays.fill(this.indexes, -1);
for (int i = 0; i < MirrorSets.this.assigned.length; i++) {
if (MirrorSets.this.assigned[i] == this) {
this.indexes[this.size] = i;
this.size++;
}
}
}
int resolve(@Nullable Object source, @Nullable A annotation,
BiFunction valueExtractor) {
int result = -1;
Object lastValue = null;
for (int i = 0; i < this.size; i++) {
Method attribute = attributes.get(this.indexes[i]);
Object value = valueExtractor.apply(attribute, annotation);
boolean isDefaultValue = (value == null ||
isEquivalentToDefaultValue(attribute, value, valueExtractor));
if (isDefaultValue || ObjectUtils.nullSafeEquals(lastValue, value)) {
if (result == -1) {
result = this.indexes[i];
}
continue;
}
if (lastValue != null && !ObjectUtils.nullSafeEquals(lastValue, value)) {
String on = (source != null) ? " declared on " + source : "";
throw new AnnotationConfigurationException(String.format(
"Different @AliasFor mirror values for annotation [%s]%s; attribute '%s' " +
"and its alias '%s' are declared with values of [%s] and [%s].",
getAnnotationType().getName(), on,
attributes.get(result).getName(),
attribute.getName(),
ObjectUtils.nullSafeToString(lastValue),
ObjectUtils.nullSafeToString(value)));
}
result = this.indexes[i];
lastValue = value;
}
return result;
}
int size() {
return this.size;
}
Method get(int index) {
int attributeIndex = this.indexes[index];
return attributes.get(attributeIndex);
}
int getAttributeIndex(int index) {
return this.indexes[index];
}
}
}
}