001/* 002 * Copyright 2002-2020 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.cache.interceptor; 018 019import java.io.IOException; 020import java.io.ObjectInputStream; 021import java.io.Serializable; 022import java.util.Arrays; 023 024import org.springframework.lang.Nullable; 025import org.springframework.util.Assert; 026import org.springframework.util.StringUtils; 027 028/** 029 * A simple key as returned from the {@link SimpleKeyGenerator}. 030 * 031 * @author Phillip Webb 032 * @author Juergen Hoeller 033 * @since 4.0 034 * @see SimpleKeyGenerator 035 */ 036@SuppressWarnings("serial") 037public class SimpleKey implements Serializable { 038 039 /** 040 * An empty key. 041 */ 042 public static final SimpleKey EMPTY = new SimpleKey(); 043 044 045 private final Object[] params; 046 047 // Effectively final, just re-calculated on deserialization 048 private transient int hashCode; 049 050 051 /** 052 * Create a new {@link SimpleKey} instance. 053 * @param elements the elements of the key 054 */ 055 public SimpleKey(Object... elements) { 056 Assert.notNull(elements, "Elements must not be null"); 057 this.params = elements.clone(); 058 // Pre-calculate hashCode field 059 this.hashCode = Arrays.deepHashCode(this.params); 060 } 061 062 063 @Override 064 public boolean equals(@Nullable Object other) { 065 return (this == other || 066 (other instanceof SimpleKey && Arrays.deepEquals(this.params, ((SimpleKey) other).params))); 067 } 068 069 @Override 070 public final int hashCode() { 071 // Expose pre-calculated hashCode field 072 return this.hashCode; 073 } 074 075 @Override 076 public String toString() { 077 return getClass().getSimpleName() + " [" + StringUtils.arrayToCommaDelimitedString(this.params) + "]"; 078 } 079 080 private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException { 081 ois.defaultReadObject(); 082 // Re-calculate hashCode field on deserialization 083 this.hashCode = Arrays.deepHashCode(this.params); 084 } 085 086}