/*
 * 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.aop.support.annotation;

import java.lang.annotation.Annotation;

import org.springframework.aop.ClassFilter;
import org.springframework.aop.MethodMatcher;
import org.springframework.aop.Pointcut;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Simple Pointcut that looks for a specific Java 5 annotation
 * being present on a {@link #forClassAnnotation class} or
 * {@link #forMethodAnnotation method}.
 *
 * @author Juergen Hoeller
 * @author Sam Brannen
 * @since 2.0
 * @see AnnotationClassFilter
 * @see AnnotationMethodMatcher
 */
public class AnnotationMatchingPointcut implements Pointcut {

        private final ClassFilter classFilter;

        private final MethodMatcher methodMatcher;


        /**
         * Create a new AnnotationMatchingPointcut for the given annotation type.
         * @param classAnnotationType the annotation type to look for at the class level
         */
        public AnnotationMatchingPointcut(Class<? extends Annotation> classAnnotationType) {
                this(classAnnotationType, false);
        }

        /**
         * Create a new AnnotationMatchingPointcut for the given annotation type.
         * @param classAnnotationType the annotation type to look for at the class level
         * @param checkInherited whether to also check the superclasses and interfaces
         * as well as meta-annotations for the annotation type
         * @see AnnotationClassFilter#AnnotationClassFilter(Class, boolean)
         */
        public AnnotationMatchingPointcut(Class<? extends Annotation> classAnnotationType, boolean checkInherited) {
                this.classFilter = new AnnotationClassFilter(classAnnotationType, checkInherited);
                this.methodMatcher = MethodMatcher.TRUE;
        }

        /**
         * Create a new AnnotationMatchingPointcut for the given annotation types.
         * @param classAnnotationType the annotation type to look for at the class level
         * (can be {@code null})
         * @param methodAnnotationType the annotation type to look for at the method level
         * (can be {@code null})
         */
        public AnnotationMatchingPointcut(@Nullable Class<? extends Annotation> classAnnotationType,
                        @Nullable Class<? extends Annotation> methodAnnotationType) {

                this(classAnnotationType, methodAnnotationType, false);
        }

        /**
         * Create a new AnnotationMatchingPointcut for the given annotation types.
         * @param classAnnotationType the annotation type to look for at the class level
         * (can be {@code null})
         * @param methodAnnotationType the annotation type to look for at the method level
         * (can be {@code null})
         * @param checkInherited whether to also check the superclasses and interfaces
         * as well as meta-annotations for the annotation type
         * @since 5.0
         * @see AnnotationClassFilter#AnnotationClassFilter(Class, boolean)
         * @see AnnotationMethodMatcher#AnnotationMethodMatcher(Class, boolean)
         */
        public AnnotationMatchingPointcut(@Nullable Class<? extends Annotation> classAnnotationType,
                        @Nullable Class<? extends Annotation> methodAnnotationType, boolean checkInherited) {

                Assert.isTrue((classAnnotationType != null || methodAnnotationType != null),
                                "Either Class annotation type or Method annotation type needs to be specified (or both)");

                if (classAnnotationType != null) {
                        this.classFilter = new AnnotationClassFilter(classAnnotationType, checkInherited);
                }
                else {
                        this.classFilter = new AnnotationCandidateClassFilter(methodAnnotationType);
                }

                if (methodAnnotationType != null) {
                        this.methodMatcher = new AnnotationMethodMatcher(methodAnnotationType, checkInherited);
                }
                else {
                        this.methodMatcher = MethodMatcher.TRUE;
                }
        }


        @Override
        public ClassFilter getClassFilter() {
                return this.classFilter;
        }

        @Override
        public MethodMatcher getMethodMatcher() {
                return this.methodMatcher;
        }

        @Override
        public boolean equals(@Nullable Object other) {
                if (this == other) {
                        return true;
                }
                if (!(other instanceof AnnotationMatchingPointcut)) {
                        return false;
                }
                AnnotationMatchingPointcut otherPointcut = (AnnotationMatchingPointcut) other;
                return (this.classFilter.equals(otherPointcut.classFilter) &&
                                this.methodMatcher.equals(otherPointcut.methodMatcher));
        }

        @Override
        public int hashCode() {
                return this.classFilter.hashCode() * 37 + this.methodMatcher.hashCode();
        }

        @Override
        public String toString() {
                return "AnnotationMatchingPointcut: " + this.classFilter + ", " + this.methodMatcher;
        }

        /**
         * Factory method for an AnnotationMatchingPointcut that matches
         * for the specified annotation at the class level.
         * @param annotationType the annotation type to look for at the class level
         * @return the corresponding AnnotationMatchingPointcut
         */
        public static AnnotationMatchingPointcut forClassAnnotation(Class<? extends Annotation> annotationType) {
                Assert.notNull(annotationType, "Annotation type must not be null");
                return new AnnotationMatchingPointcut(annotationType);
        }

        /**
         * Factory method for an AnnotationMatchingPointcut that matches
         * for the specified annotation at the method level.
         * @param annotationType the annotation type to look for at the method level
         * @return the corresponding AnnotationMatchingPointcut
         */
        public static AnnotationMatchingPointcut forMethodAnnotation(Class<? extends Annotation> annotationType) {
                Assert.notNull(annotationType, "Annotation type must not be null");
                return new AnnotationMatchingPointcut(null, annotationType);
        }


        /**
         * {@link ClassFilter} that delegates to {@link AnnotationUtils#isCandidateClass}
         * for filtering classes whose methods are not worth searching to begin with.
         * @since 5.2
         */
        private static class AnnotationCandidateClassFilter implements ClassFilter {

                private final Class<? extends Annotation> annotationType;

                AnnotationCandidateClassFilter(Class<? extends Annotation> annotationType) {
                        this.annotationType = annotationType;
                }

                @Override
                public boolean matches(Class<?> clazz) {
                        return AnnotationUtils.isCandidateClass(clazz, this.annotationType);
                }

                @Override
                public boolean equals(Object obj) {
                        if (this == obj) {
                                return true;
                        }
                        if (!(obj instanceof AnnotationCandidateClassFilter)) {
                                return false;
                        }
                        AnnotationCandidateClassFilter that = (AnnotationCandidateClassFilter) obj;
                        return this.annotationType.equals(that.annotationType);
                }

                @Override
                public int hashCode() {
                        return this.annotationType.hashCode();
                }

                @Override
                public String toString() {
                        return getClass().getName() + ": " + this.annotationType;
                }

        }

}