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Dson对象序列化模块
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/*
 * Copyright 2023-2024 wjybxx([email protected])
 *
 * 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
 *
 *     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 cn.wjybxx.dson.codec;

import java.util.*;

/**
 * 类型id的写入策略
 *
 * @author wjybxx
 * date - 2023/4/27
 */
public enum ClassIdPolicy {

    /**
     * 当对象的运行时类型和声明类型相同时不写入类型信息
     * 通常我们的字段类型定义是明确的，因此可以省去大量不必要的类型信息。
     * 如果仅用于java或其它静态类型语言，建议使用该模式。
     */
    OPTIMIZED,

    /**
     * 总是写入对象的类型信息，无论运行时类型与声明类型是否相同
     * 这种方式有更好的兼容性，对跨语言友好，因为目标语言可能没有泛型，或没有注解处理器生成辅助代码等
     */
    ALWAYS,

    /**
     * 总是不写入对象的类型信息，无论运行时类型与声明类型是否相同
     */
    NONE;

    public boolean test(Class declared, Class encodeClass) {
        return switch (this) {
            case NONE -> false;
            case ALWAYS -> true;
            case OPTIMIZED -> {
                if (encodeClass == declared) {
                    yield false;
                }
                // 默认解码类型的父类型无需写入，List/Map/Set
                if (encodeClass == ArrayList.class) {
                    yield false;
                }
                if ((encodeClass == HashMap.class || encodeClass == LinkedHashMap.class)
                        && Map.class.isAssignableFrom(declared)) {
                    yield false;
                }
                if ((encodeClass == HashSet.class || encodeClass == LinkedHashSet.class)
                        && Set.class.isAssignableFrom(declared)) {
                    yield false;
                }
                yield true;
            }
        };
    }

}