/*            *  Licensed to the Apache Software Foundation (ASF) under one or more            *  contributor license agreements.  See the NOTICE file distributed with            *  this work for additional information regarding copyright ownership.            *  The ASF licenses this file to You 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            *            *      http://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.apache.commons.collections.map;            
import java.io.IOException;            import java.io.ObjectInputStream;            import java.io.ObjectOutputStream;            import java.io.Serializable;            import java.util.Iterator;            import java.util.Map;            
import org.apache.commons.collections.Transformer;            
/**              * Decorates another Map to transform objects that are added.              *  * The Map put methods and Map.Entry setValue method are affected by this class.      * Thus objects must be removed or searched for using their transformed form.      * For example, if the transformation converts Strings to Integers, you must      * use the Integer form to remove objects.      *
  *Note that TransformedMap is not synchronized and is not thread-safe.      * If you wish to use this map from multiple threads concurrently, you must use      * appropriate synchronization. The simplest approach is to wrap this map      * using {@link java.util.Collections#synchronizedMap(Map)}. This class may throw      * exceptions when accessed by concurrent threads without synchronization.      *
  * This class is Serializable from Commons Collections 3.1.      *      * @since Commons Collections 3.0      * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $      *      * @author Stephen Colebourne    */
public class TransformedMap extends AbstractInputCheckedMapDecorator implements Serializable {    
/** Serialization version */    private static final long serialVersionUID = 7023152376788900464L;    
/** The transformer to use for the key */    protected final Transformer keyTransformer;    /** The transformer to use for the value */    protected final Transformer valueTransformer;    
/**         * Factory method to create a transforming map.         *
     * If there are any elements already in the map being decorated, they         * are NOT transformed.         * Constrast this with {@link #decorateTransform}.         *         * @param map  the map to decorate, must not be null         * @param keyTransformer  the transformer to use for key conversion, null means no transformation         * @param valueTransformer  the transformer to use for value conversion, null means no transformation         * @throws IllegalArgumentException if map is null         */    public static Map decorate(Map map, Transformer keyTransformer, Transformer valueTransformer) {            return new TransformedMap(map, keyTransformer, valueTransformer);        }    
    //-----------------------------------------------------------------------/**         * Constructor that wraps (not copies).         *
     * If there are any elements already in the collection being decorated, they         * are NOT transformed.         *         * @param map  the map to decorate, must not be null         * @param keyTransformer  the transformer to use for key conversion, null means no conversion         * @param valueTransformer  the transformer to use for value conversion, null means no conversion         * @throws IllegalArgumentException if map is null         */protected TransformedMap(Map map, Transformer keyTransformer, Transformer valueTransformer) {            super(map);            this.keyTransformer = keyTransformer;            this.valueTransformer = valueTransformer;        }    
    //-----------------------------------------------------------------------/**         * Transforms a key.         *
     * The transformer itself may throw an exception if necessary.         *         * @param object  the object to transform         * @throws the transformed object         */protected Object transformKey(Object object) {            if (keyTransformer == null) {                return object;            }    return keyTransformer.transform(object);        }    
/**         * Transforms a value.         *
     * The transformer itself may throw an exception if necessary.         *         * @param object  the object to transform         * @throws the transformed object         */protected Object transformValue(Object object) {            if (valueTransformer == null) {                return object;            }    return valueTransformer.transform(object);        }    
/**         * Override to transform the value when usingsetValue.         *         * @param value  the value to transform         * @return the transformed value         * @since Commons Collections 3.1         */protected Object checkSetValue(Object value) {            return valueTransformer.transform(value);        }    
    //-----------------------------------------------------------------------public Object put(Object key, Object value) {            key = transformKey(key);            value = transformValue(value);            return getMap().put(key, value);        }    
}

InvokerTransformer.transform()TransformedMap.checkSetvalue()AbstractInputCheckedMapDecorator.Map.Entry.setValue()AnnotationInvocationHandler.readObject()

HashMap的内部类Node与Map的内部类Entry的关系以及Node与Entry、EntrySet三者之间的关系：https://blog.csdn.net/weixin_46195957/article/details/125314612Map.Entry的定义https://blog.csdn.net/please93/article/details/121866493