001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.context.expression;
018
019import java.lang.reflect.AnnotatedElement;
020
021import org.springframework.lang.Nullable;
022import org.springframework.util.Assert;
023import org.springframework.util.ObjectUtils;
024
025/**
026 * Represent an {@link AnnotatedElement} on a particular {@link Class}
027 * and is suitable as a key.
028 *
029 * @author Costin Leau
030 * @author Stephane Nicoll
031 * @since 4.2
032 * @see CachedExpressionEvaluator
033 */
034public final class AnnotatedElementKey implements Comparable<AnnotatedElementKey> {
035
036        private final AnnotatedElement element;
037
038        @Nullable
039        private final Class<?> targetClass;
040
041
042        /**
043         * Create a new instance with the specified {@link AnnotatedElement} and
044         * optional target {@link Class}.
045         */
046        public AnnotatedElementKey(AnnotatedElement element, @Nullable Class<?> targetClass) {
047                Assert.notNull(element, "AnnotatedElement must not be null");
048                this.element = element;
049                this.targetClass = targetClass;
050        }
051
052
053        @Override
054        public boolean equals(@Nullable Object other) {
055                if (this == other) {
056                        return true;
057                }
058                if (!(other instanceof AnnotatedElementKey)) {
059                        return false;
060                }
061                AnnotatedElementKey otherKey = (AnnotatedElementKey) other;
062                return (this.element.equals(otherKey.element) &&
063                                ObjectUtils.nullSafeEquals(this.targetClass, otherKey.targetClass));
064        }
065
066        @Override
067        public int hashCode() {
068                return this.element.hashCode() + (this.targetClass != null ? this.targetClass.hashCode() * 29 : 0);
069        }
070
071        @Override
072        public String toString() {
073                return this.element + (this.targetClass != null ? " on " + this.targetClass : "");
074        }
075
076        @Override
077        public int compareTo(AnnotatedElementKey other) {
078                int result = this.element.toString().compareTo(other.element.toString());
079                if (result == 0 && this.targetClass != null) {
080                        if (other.targetClass == null) {
081                                return 1;
082                        }
083                        result = this.targetClass.getName().compareTo(other.targetClass.getName());
084                }
085                return result;
086        }
087
088}