/*
 * 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.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.annotation.Inherited;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import javax.annotation.Nullable;

import org.junit.jupiter.api.Test;

import org.springframework.core.annotation.AnnotationTypeMapping.MirrorSets;
import org.springframework.core.annotation.AnnotationTypeMapping.MirrorSets.MirrorSet;
import org.springframework.lang.UsesSunMisc;
import org.springframework.util.ReflectionUtils;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

/**
 * Tests for {@link AnnotationTypeMappings} and {@link AnnotationTypeMapping}.
 *
 * @author Phillip Webb
 */
class AnnotationTypeMappingsTests {

	@Test
	void forAnnotationTypeWhenNoMetaAnnotationsReturnsMappings() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(SimpleAnnotation.class);
		assertThat(mappings.size()).isEqualTo(1);
		assertThat(mappings.get(0).getAnnotationType()).isEqualTo(SimpleAnnotation.class);
		assertThat(getAll(mappings)).flatExtracting(
				AnnotationTypeMapping::getAnnotationType).containsExactly(SimpleAnnotation.class);
	}

	@Test
	void forAnnotationWhenHasSpringAnnotationReturnsFilteredMappings() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(WithSpringLangAnnotation.class);
		assertThat(mappings.size()).isEqualTo(1);
	}

	@Test
	void forAnnotationTypeWhenMetaAnnotationsReturnsMappings() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(MetaAnnotated.class);
		assertThat(mappings.size()).isEqualTo(6);
		assertThat(getAll(mappings)).flatExtracting(
				AnnotationTypeMapping::getAnnotationType).containsExactly(
						MetaAnnotated.class, A.class, B.class, AA.class, AB.class,
						ABC.class);
	}

	@Test
	void forAnnotationTypeWhenHasRepeatingMetaAnnotationReturnsMapping() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(WithRepeatedMetaAnnotations.class);
		assertThat(mappings.size()).isEqualTo(3);
		assertThat(getAll(mappings)).flatExtracting(
				AnnotationTypeMapping::getAnnotationType).containsExactly(
						WithRepeatedMetaAnnotations.class, Repeating.class, Repeating.class);
	}

	@Test
	void forAnnotationTypeWhenSelfAnnotatedReturnsMapping() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(SelfAnnotated.class);
		assertThat(mappings.size()).isEqualTo(1);
		assertThat(getAll(mappings)).flatExtracting(
				AnnotationTypeMapping::getAnnotationType).containsExactly(SelfAnnotated.class);
	}

	@Test
	void forAnnotationTypeWhenFormsLoopReturnsMapping() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(LoopA.class);
		assertThat(mappings.size()).isEqualTo(2);
		assertThat(getAll(mappings)).flatExtracting(
				AnnotationTypeMapping::getAnnotationType).containsExactly(LoopA.class, LoopB.class);
	}

	@Test
	void forAnnotationTypeWhenHasAliasForWithBothValueAndAttributeThrowsException() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForWithBothValueAndAttribute.class))
			.withMessage("In @AliasFor declared on attribute 'test' in annotation ["
								+ AliasForWithBothValueAndAttribute.class.getName()
								+ "], attribute 'attribute' and its alias 'value' are present with values of 'foo' and 'bar', but only one is permitted.");
	}

	@Test
	void forAnnotationTypeWhenAliasForToSelfNonExistingAttribute() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForToSelfNonExistingAttribute.class))
			.withMessage("@AliasFor declaration on attribute 'test' in annotation ["
								+ AliasForToSelfNonExistingAttribute.class.getName()
								+ "] declares an alias for 'missing' which is not present.");
	}

	@Test
	void forAnnotationTypeWhenAliasForToOtherNonExistingAttribute() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForToOtherNonExistingAttribute.class))
			.withMessage("Attribute 'test' in annotation ["
								+ AliasForToOtherNonExistingAttribute.class.getName()
								+ "] is declared as an @AliasFor nonexistent "
								+ "attribute 'missing' in annotation ["
								+ AliasForToOtherNonExistingAttributeTarget.class.getName()
								+ "].");
	}

	@Test
	void forAnnotationTypeWhenAliasForToSelf() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForToSelf.class))
			.withMessage("@AliasFor declaration on attribute 'test' in annotation ["
								+ AliasForToSelf.class.getName()
								+ "] points to itself. Specify 'annotation' to point to "
								+ "a same-named attribute on a meta-annotation.");
	}

	@Test
	void forAnnotationTypeWhenAliasForWithArrayCompatibleReturnTypes() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				AliasForWithArrayCompatibleReturnTypes.class);
		AnnotationTypeMapping mapping = getMapping(mappings,
				AliasForWithArrayCompatibleReturnTypesTarget.class);
		assertThat(getAliasMapping(mapping, 0).getName()).isEqualTo("test");
	}

	@Test
	void forAnnotationTypeWhenAliasForWithIncompatibleReturnTypes() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForWithIncompatibleReturnTypes.class))
			.withMessage("Misconfigured aliases: attribute 'test' in annotation ["
								+ AliasForWithIncompatibleReturnTypes.class.getName()
								+ "] and attribute 'test' in annotation ["
								+ AliasForWithIncompatibleReturnTypesTarget.class.getName()
								+ "] must declare the same return type.");
	}

	@Test
	void forAnnotationTypeWhenAliasForToSelfAnnotatedToOtherAttribute() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForToSelfAnnotatedToOtherAttribute.class))
			.withMessage("Attribute 'b' in annotation ["
								+ AliasForToSelfAnnotatedToOtherAttribute.class.getName()
								+ "] must be declared as an @AliasFor 'a', not 'c'.");
	}

	@Test
	void forAnnotationTypeWhenAliasForNonMetaAnnotated() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForNonMetaAnnotated.class))
			.withMessage("@AliasFor declaration on attribute 'test' in annotation ["
								+ AliasForNonMetaAnnotated.class.getName()
								+ "] declares an alias for attribute 'test' in annotation ["
								+ AliasForNonMetaAnnotatedTarget.class.getName()
								+ "] which is not meta-present.");
	}

	@Test
	void forAnnotationTypeWhenAliasForSelfWithDifferentDefaults() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForSelfWithDifferentDefaults.class))
			.withMessage("Misconfigured aliases: attribute 'a' in annotation ["
								+ AliasForSelfWithDifferentDefaults.class.getName()
								+ "] and attribute 'b' in annotation ["
								+ AliasForSelfWithDifferentDefaults.class.getName()
								+ "] must declare the same default value.");
	}

	@Test
	void forAnnotationTypeWhenAliasForSelfWithMissingDefault() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasForSelfWithMissingDefault.class))
			.withMessage("Misconfigured aliases: attribute 'a' in annotation ["
									+ AliasForSelfWithMissingDefault.class.getName()
									+ "] and attribute 'b' in annotation ["
									+ AliasForSelfWithMissingDefault.class.getName()
									+ "] must declare default values.");
	}

	@Test
	void forAnnotationTypeWhenAliasWithExplicitMirrorAndDifferentDefaults() {
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				AnnotationTypeMappings.forAnnotationType(AliasWithExplicitMirrorAndDifferentDefaults.class))
			.withMessage("Misconfigured aliases: attribute 'a' in annotation ["
								+ AliasWithExplicitMirrorAndDifferentDefaults.class.getName()
								+ "] and attribute 'c' in annotation ["
								+ AliasWithExplicitMirrorAndDifferentDefaults.class.getName()
								+ "] must declare the same default value.");
	}

	@Test
	void getDistanceReturnsDistance() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				Mapped.class);
		assertThat(mappings.get(0).getDistance()).isEqualTo(0);
		assertThat(mappings.get(1).getDistance()).isEqualTo(1);
	}

	@Test
	void getAnnotationTypeReturnsAnnotationType() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				Mapped.class);
		assertThat(mappings.get(0).getAnnotationType()).isEqualTo(Mapped.class);
		assertThat(mappings.get(1).getAnnotationType()).isEqualTo(MappedTarget.class);
	}

	@Test
	void getMetaTypeReturnsTypes() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				ThreeDeepA.class);
		AnnotationTypeMapping mappingC = mappings.get(2);
		assertThat(mappingC.getMetaTypes()).containsExactly(
				ThreeDeepA.class, ThreeDeepB.class, ThreeDeepC.class);
	}

	@Test
	void getAnnotationWhenRootReturnsNull() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				Mapped.class);
		assertThat(mappings.get(0).getAnnotation()).isNull();
	}

	@Test
	void getAnnotationWhenMetaAnnotationReturnsAnnotation() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				Mapped.class);
		assertThat(mappings.get(1).getAnnotation()).isEqualTo(
				Mapped.class.getAnnotation(MappedTarget.class));

	}

	@Test
	void getAttributesReturnsAttributes() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				Mapped.class).get(0);
		AttributeMethods attributes = mapping.getAttributes();
		assertThat(attributes.size()).isEqualTo(2);
		assertThat(attributes.get(0).getName()).isEqualTo("alias");
		assertThat(attributes.get(1).getName()).isEqualTo("convention");
	}

	@Test
	void getAliasMappingReturnsAttributes() throws Exception {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				Mapped.class).get(1);
		assertThat(getAliasMapping(mapping, 0)).isEqualTo(
				Mapped.class.getDeclaredMethod("alias"));
	}

	@Test
	void getConventionMappingReturnsAttributes() throws Exception {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				Mapped.class).get(1);
		assertThat(getConventionMapping(mapping, 1)).isEqualTo(
				Mapped.class.getDeclaredMethod("convention"));
	}

	@Test
	void getMirrorSetWhenAliasPairReturnsMirrors() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				AliasPair.class).get(0);
		MirrorSets mirrorSets = mapping.getMirrorSets();
		assertThat(mirrorSets.size()).isEqualTo(1);
		assertThat(mirrorSets.get(0).size()).isEqualTo(2);
		assertThat(mirrorSets.get(0).get(0).getName()).isEqualTo("a");
		assertThat(mirrorSets.get(0).get(1).getName()).isEqualTo("b");
	}

	@Test
	void getMirrorSetWhenImplicitMirrorsReturnsMirrors() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ImplicitMirrors.class).get(0);
		MirrorSets mirrorSets = mapping.getMirrorSets();
		assertThat(mirrorSets.size()).isEqualTo(1);
		assertThat(mirrorSets.get(0).size()).isEqualTo(2);
		assertThat(mirrorSets.get(0).get(0).getName()).isEqualTo("a");
		assertThat(mirrorSets.get(0).get(1).getName()).isEqualTo("b");
	}

	@Test
	void getMirrorSetWhenThreeDeepReturnsMirrors() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				ThreeDeepA.class);
		AnnotationTypeMapping mappingA = mappings.get(0);
		MirrorSets mirrorSetsA = mappingA.getMirrorSets();
		assertThat(mirrorSetsA.size()).isEqualTo(2);
		assertThat(getNames(mirrorSetsA.get(0))).containsExactly("a1", "a2", "a3");
		AnnotationTypeMapping mappingB = mappings.get(1);
		MirrorSets mirrorSetsB = mappingB.getMirrorSets();
		assertThat(mirrorSetsB.size()).isEqualTo(1);
		assertThat(getNames(mirrorSetsB.get(0))).containsExactly("b1", "b2");
		AnnotationTypeMapping mappingC = mappings.get(2);
		MirrorSets mirrorSetsC = mappingC.getMirrorSets();
		assertThat(mirrorSetsC.size()).isEqualTo(0);
	}

	@Test
	void getAliasMappingWhenThreeDeepReturnsMappedAttributes() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				ThreeDeepA.class);
		AnnotationTypeMapping mappingA = mappings.get(0);
		assertThat(getAliasMapping(mappingA, 0)).isNull();
		assertThat(getAliasMapping(mappingA, 1)).isNull();
		assertThat(getAliasMapping(mappingA, 2)).isNull();
		assertThat(getAliasMapping(mappingA, 3)).isNull();
		assertThat(getAliasMapping(mappingA, 4)).isNull();
		AnnotationTypeMapping mappingB = mappings.get(1);
		assertThat(getAliasMapping(mappingB, 0).getName()).isEqualTo("a1");
		assertThat(getAliasMapping(mappingB, 1).getName()).isEqualTo("a1");
		AnnotationTypeMapping mappingC = mappings.get(2);
		assertThat(getAliasMapping(mappingC, 0).getName()).isEqualTo("a1");
		assertThat(getAliasMapping(mappingC, 1).getName()).isEqualTo("a4");
	}

	@Test
	void getAliasMappingsWhenHasDefinedAttributesReturnsMappedAttributes() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				DefinedAttributes.class).get(1);
		assertThat(getAliasMapping(mapping, 0)).isNull();
		assertThat(getAliasMapping(mapping, 1).getName()).isEqualTo("value");
	}

	@Test
	void resolveMirrorsWhenAliasPairResolves() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				AliasPair.class).get(0);
		Method[] resolvedA = resolveMirrorSets(mapping, WithAliasPairA.class,
				AliasPair.class);
		assertThat(resolvedA[0].getName()).isEqualTo("a");
		assertThat(resolvedA[1].getName()).isEqualTo("a");
		Method[] resolvedB = resolveMirrorSets(mapping, WithAliasPairB.class,
				AliasPair.class);
		assertThat(resolvedB[0].getName()).isEqualTo("b");
		assertThat(resolvedB[1].getName()).isEqualTo("b");
	}

	@Test
	void resolveMirrorsWhenHasSameValuesUsesFirst() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				AliasPair.class).get(0);
		Method[] resolved = resolveMirrorSets(mapping, WithSameValueAliasPair.class,
				AliasPair.class);
		assertThat(resolved[0].getName()).isEqualTo("a");
		assertThat(resolved[1].getName()).isEqualTo("a");
	}

	@Test
	void resolveMirrorsWhenOnlyHasDefaultValuesResolvesNone() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				AliasPair.class).get(0);
		Method[] resolved = resolveMirrorSets(mapping, WithDefaultValueAliasPair.class,
				AliasPair.class);
		assertThat(resolved[0]).isNull();
		assertThat(resolved[1]).isNull();
	}

	@Test
	void resolveMirrorsWhenHasDifferentValuesThrowsException() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				AliasPair.class).get(0);
		assertThatExceptionOfType(AnnotationConfigurationException.class).isThrownBy(() ->
				resolveMirrorSets(mapping, WithDifferentValueAliasPair.class, AliasPair.class))
			.withMessage("Different @AliasFor mirror values for annotation ["
								+ AliasPair.class.getName() + "] declared on "
								+ WithDifferentValueAliasPair.class.getName()
								+ "; attribute 'a' and its alias 'b' are declared with values of [test1] and [test2].");
	}

	@Test
	void resolveMirrorsWhenHasWithMulipleRoutesToAliasReturnsMirrors() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				MulipleRoutesToAliasA.class);
		AnnotationTypeMapping mappingsA = getMapping(mappings,
				MulipleRoutesToAliasA.class);
		assertThat(mappingsA.getMirrorSets().size()).isZero();
		AnnotationTypeMapping mappingsB = getMapping(mappings,
				MulipleRoutesToAliasB.class);
		assertThat(getNames(mappingsB.getMirrorSets().get(0))).containsExactly("b1", "b2",
				"b3");
		AnnotationTypeMapping mappingsC = getMapping(mappings,
				MulipleRoutesToAliasC.class);
		assertThat(getNames(mappingsC.getMirrorSets().get(0))).containsExactly("c1",
				"c2");
	}

	@Test
	void getAliasMappingWhenHasWithMulipleRoutesToAliasReturnsMappedAttributes() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				MulipleRoutesToAliasA.class);
		AnnotationTypeMapping mappingsA = getMapping(mappings,
				MulipleRoutesToAliasA.class);
		assertThat(getAliasMapping(mappingsA, 0)).isNull();
		AnnotationTypeMapping mappingsB = getMapping(mappings,
				MulipleRoutesToAliasB.class);
		assertThat(getAliasMapping(mappingsB, 0).getName()).isEqualTo("a1");
		assertThat(getAliasMapping(mappingsB, 1).getName()).isEqualTo("a1");
		assertThat(getAliasMapping(mappingsB, 2).getName()).isEqualTo("a1");
		AnnotationTypeMapping mappingsC = getMapping(mappings,
				MulipleRoutesToAliasC.class);
		assertThat(getAliasMapping(mappingsC, 0).getName()).isEqualTo("a1");
		assertThat(getAliasMapping(mappingsC, 1).getName()).isEqualTo("a1");
	}

	@Test
	void getConventionMappingWhenConventionToExplicitAliasesReturnsMappedAttributes() {
		AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
				ConventionToExplicitAliases.class);
		AnnotationTypeMapping mapping = getMapping(mappings,
				ConventionToExplicitAliasesTarget.class);
		assertThat(mapping.getConventionMapping(0)).isEqualTo(0);
		assertThat(mapping.getConventionMapping(1)).isEqualTo(0);
	}

	@Test
	void isEquivalentToDefaultValueWhenValueAndDefaultAreNullReturnsTrue() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ClassValue.class).get(0);
		assertThat(mapping.isEquivalentToDefaultValue(0, null,
				ReflectionUtils::invokeMethod)).isTrue();
	}

	@Test
	void isEquivalentToDefaultValueWhenValueAndDefaultMatchReturnsTrue() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ClassValueWithDefault.class).get(0);
		assertThat(mapping.isEquivalentToDefaultValue(0, InputStream.class,
				ReflectionUtils::invokeMethod)).isTrue();
	}

	@Test
	void isEquivalentToDefaultValueWhenClassAndStringNamesMatchReturnsTrue() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ClassValueWithDefault.class).get(0);
		assertThat(mapping.isEquivalentToDefaultValue(0, "java.io.InputStream",
				ReflectionUtils::invokeMethod)).isTrue();
	}

	@Test
	void isEquivalentToDefaultValueWhenClassArrayAndStringArrayNamesMatchReturnsTrue() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ClassArrayValueWithDefault.class).get(0);
		assertThat(mapping.isEquivalentToDefaultValue(0,
				new String[] { "java.io.InputStream", "java.io.OutputStream" },
				ReflectionUtils::invokeMethod)).isTrue();
	}

	@Test
	void isEquivalentToDefaultValueWhenNestedAnnotationAndExtractedValuesMatchReturnsTrue() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				NestedValue.class).get(0);
		Map<String, Object> value = Collections.singletonMap("value",
				"java.io.InputStream");
		assertThat(mapping.isEquivalentToDefaultValue(0, value,
				this::extractFromMap)).isTrue();
	}

	@Test
	void isEquivalentToDefaultValueWhenNotMatchingReturnsFalse() {
		AnnotationTypeMapping mapping = AnnotationTypeMappings.forAnnotationType(
				ClassValueWithDefault.class).get(0);
		assertThat(mapping.isEquivalentToDefaultValue(0, OutputStream.class,
				ReflectionUtils::invokeMethod)).isFalse();
	}

	private Method[] resolveMirrorSets(AnnotationTypeMapping mapping, Class<?> element,
			Class<? extends Annotation> annotationClass) {
		Annotation annotation = element.getAnnotation(annotationClass);
		int[] resolved = mapping.getMirrorSets().resolve(element.getName(), annotation,
				ReflectionUtils::invokeMethod);
		Method[] result = new Method[resolved.length];
		for (int i = 0; i < resolved.length; i++) {
			result[i] = resolved[i] != -1 ? mapping.getAttributes().get(resolved[i])
					: null;
		}
		return result;
	}

	@Nullable
	private Method getAliasMapping(AnnotationTypeMapping mapping, int attributeIndex) {
		int mapped = mapping.getAliasMapping(attributeIndex);
		return mapped != -1 ? mapping.getRoot().getAttributes().get(mapped) : null;
	}

	@Nullable
	private Method getConventionMapping(AnnotationTypeMapping mapping,
			int attributeIndex) {
		int mapped = mapping.getConventionMapping(attributeIndex);
		return mapped != -1 ? mapping.getRoot().getAttributes().get(mapped) : null;
	}

	private AnnotationTypeMapping getMapping(AnnotationTypeMappings mappings,
			Class<? extends Annotation> annotationType) {
		for (AnnotationTypeMapping candidate : getAll(mappings)) {
			if (candidate.getAnnotationType() == annotationType) {
				return candidate;
			}
		}
		return null;
	}

	private List<AnnotationTypeMapping> getAll(AnnotationTypeMappings mappings) {
		// AnnotationTypeMappings does not implement Iterable so we don't create
		// too many garbage Iterators
		List<AnnotationTypeMapping> result = new ArrayList<>(mappings.size());
		for (int i = 0; i < mappings.size(); i++) {
			result.add(mappings.get(i));
		}
		return result;
	}

	private List<String> getNames(MirrorSet mirrorSet) {
		List<String> names = new ArrayList<>(mirrorSet.size());
		for (int i = 0; i < mirrorSet.size(); i++) {
			names.add(mirrorSet.get(i).getName());
		}
		return names;
	}

	@SuppressWarnings("unchecked")
	private Object extractFromMap(Method attribute, Object map) {
		return map != null ? ((Map<String, ?>) map).get(attribute.getName()) : null;
	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface SimpleAnnotation {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@Inherited
	@UsesSunMisc
	@interface WithSpringLangAnnotation {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@A
	@B
	@interface MetaAnnotated {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@AA
	@AB
	@interface A {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AA {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@ABC
	@interface AB {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ABC {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface B {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@Repeating
	@Repeating
	@interface WithRepeatedMetaAnnotations {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@Repeatable(Repeatings.class)
	@interface Repeating {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface Repeatings {

		Repeating[] value();

	}

	@Retention(RetentionPolicy.RUNTIME)
	@SelfAnnotated
	@interface SelfAnnotated {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@LoopB
	@interface LoopA {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@LoopA
	@interface LoopB {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForWithBothValueAndAttribute {

		@AliasFor(value = "bar", attribute = "foo")
		String test();

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForToSelfNonExistingAttribute {

		@AliasFor("missing")
		String test() default "";

		String other() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@AliasForToOtherNonExistingAttributeTarget
	@interface AliasForToOtherNonExistingAttribute {

		@AliasFor(annotation = AliasForToOtherNonExistingAttributeTarget.class, attribute = "missing")
		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForToOtherNonExistingAttributeTarget {

		String other() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForToSelf {

		@AliasFor("test")
		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@AliasForWithArrayCompatibleReturnTypesTarget
	@interface AliasForWithArrayCompatibleReturnTypes {

		@AliasFor(annotation = AliasForWithArrayCompatibleReturnTypesTarget.class)
		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForWithArrayCompatibleReturnTypesTarget {

		String[] test() default {};

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForWithIncompatibleReturnTypes {

		@AliasFor(annotation = AliasForWithIncompatibleReturnTypesTarget.class)
		String[] test() default {};

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForWithIncompatibleReturnTypesTarget {

		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForToSelfAnnotatedToOtherAttribute {

		@AliasFor("b")
		String a() default "";

		@AliasFor("c")
		String b() default "";

		@AliasFor("a")
		String c() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForNonMetaAnnotated {

		@AliasFor(annotation = AliasForNonMetaAnnotatedTarget.class)
		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForNonMetaAnnotatedTarget {

		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForSelfWithDifferentDefaults {

		@AliasFor("b")
		String a() default "a";

		@AliasFor("a")
		String b() default "b";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasForSelfWithMissingDefault {

		@AliasFor("b")
		String a() default "a";

		@AliasFor("a")
		String b();

	}

	@Retention(RetentionPolicy.RUNTIME)
	@AliasWithExplicitMirrorAndDifferentDefaultsTarget
	@interface AliasWithExplicitMirrorAndDifferentDefaults {

		@AliasFor(annotation = AliasWithExplicitMirrorAndDifferentDefaultsTarget.class, attribute = "a")
		String a() default "x";

		@AliasFor(annotation = AliasWithExplicitMirrorAndDifferentDefaultsTarget.class, attribute = "a")
		String b() default "x";

		@AliasFor(annotation = AliasWithExplicitMirrorAndDifferentDefaultsTarget.class, attribute = "a")
		String c() default "y";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasWithExplicitMirrorAndDifferentDefaultsTarget {

		String a() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@MappedTarget
	@interface Mapped {

		String convention() default "";

		@AliasFor(annotation = MappedTarget.class, attribute = "aliasTarget")
		String alias() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface MappedTarget {

		String convention() default "";

		String aliasTarget() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface AliasPair {

		@AliasFor("b")
		String a() default "";

		@AliasFor("a")
		String b() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@ImplicitMirrorsTarget
	@interface ImplicitMirrors {

		@AliasFor(annotation = ImplicitMirrorsTarget.class, attribute = "c")
		String a() default "";

		@AliasFor(annotation = ImplicitMirrorsTarget.class, attribute = "c")
		String b() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ImplicitMirrorsTarget {

		@AliasFor("d")
		String c() default "";

		@AliasFor("c")
		String d() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@ThreeDeepB
	@interface ThreeDeepA {

		@AliasFor(annotation = ThreeDeepB.class, attribute = "b1")
		String a1() default "";

		@AliasFor(annotation = ThreeDeepB.class, attribute = "b2")
		String a2() default "";

		@AliasFor(annotation = ThreeDeepC.class, attribute = "c1")
		String a3() default "";

		@AliasFor(annotation = ThreeDeepC.class, attribute = "c2")
		String a4() default "";

		@AliasFor(annotation = ThreeDeepC.class, attribute = "c2")
		String a5() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@ThreeDeepC
	@interface ThreeDeepB {

		@AliasFor(annotation = ThreeDeepC.class, attribute = "c1")
		String b1() default "";

		@AliasFor(annotation = ThreeDeepC.class, attribute = "c1")
		String b2() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ThreeDeepC {

		String c1() default "";

		String c2() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@DefinedAttributesTarget(a = "test")
	@interface DefinedAttributes {

		@AliasFor(annotation = DefinedAttributesTarget.class, attribute = "b")
		String value();

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface DefinedAttributesTarget {

		String a();

		String b() default "";

	}

	@AliasPair(a = "test")
	static class WithAliasPairA {

	}

	@AliasPair(b = "test")
	static class WithAliasPairB {

	}

	@AliasPair(a = "test", b = "test")
	static class WithSameValueAliasPair {

	}

	@AliasPair(a = "test1", b = "test2")
	static class WithDifferentValueAliasPair {

	}

	@AliasPair
	static class WithDefaultValueAliasPair {

	}

	@Retention(RetentionPolicy.RUNTIME)
	@MulipleRoutesToAliasB
	@interface MulipleRoutesToAliasA {

		@AliasFor(annotation = MulipleRoutesToAliasB.class, attribute = "b2")
		String a1() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@MulipleRoutesToAliasC
	@interface MulipleRoutesToAliasB {

		@AliasFor(annotation = MulipleRoutesToAliasC.class, attribute = "c2")
		String b1() default "";

		@AliasFor(annotation = MulipleRoutesToAliasC.class, attribute = "c2")
		String b2() default "";

		@AliasFor(annotation = MulipleRoutesToAliasC.class, attribute = "c1")
		String b3() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface MulipleRoutesToAliasC {

		@AliasFor("c2")
		String c1() default "";

		@AliasFor("c1")
		String c2() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@ConventionToExplicitAliasesTarget
	@interface ConventionToExplicitAliases {

		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ConventionToExplicitAliasesTarget {

		@AliasFor("test")
		String value() default "";

		@AliasFor("value")
		String test() default "";

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ClassValue {

		Class<?> value();

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ClassValueWithDefault {

		Class<?> value() default InputStream.class;

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface ClassArrayValueWithDefault {

		Class<?>[] value() default { InputStream.class, OutputStream.class };

	}

	@Retention(RetentionPolicy.RUNTIME)
	@interface NestedValue {

		ClassValue value() default @ClassValue(InputStream.class);

	}

}
