/*
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* Copyright (c) 2011-2020, baomidou (jobob@qq.com).
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* <p>
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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* <p>
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* https://www.apache.org/licenses/LICENSE-2.0
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* <p>
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.yuanchu.mom.numgen;
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import com.baomidou.mybatisplus.core.metadata.TableInfo;
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import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
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import com.baomidou.mybatisplus.core.toolkit.StringUtils;
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import com.baomidou.mybatisplus.core.toolkit.support.ColumnCache;
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import com.baomidou.mybatisplus.core.toolkit.support.SFunction;
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import java.lang.ref.WeakReference;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.Optional;
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import java.util.concurrent.ConcurrentHashMap;
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import static java.util.Locale.ENGLISH;
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/**
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* Lambda 解析工具类
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*
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* @author HCL, MieMie
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* @since 2018-05-10
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*/
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public final class LambdaUtils {
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/**
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* 字段映射
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*/
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private static final Map<String, Map<String, ColumnCache>> COLUMN_CACHE_MAP = new ConcurrentHashMap<>();
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/**
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* SerializedLambda 反序列化缓存
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*/
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private static final Map<String, WeakReference<SerializedLambda>> FUNC_CACHE = new ConcurrentHashMap<>();
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/**
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* 解析 lambda 表达式, 该方法只是调用了 {@link SerializedLambda#resolve(SFunction)} 中的方法，在此基础上加了缓存。
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* 该缓存可能会在任意不定的时间被清除
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*
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* @param func 需要解析的 lambda 对象
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* @param <T> 类型，被调用的 Function 对象的目标类型
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* @return 返回解析后的结果
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* @see SerializedLambda#resolve(SFunction)
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*/
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public static <T> SerializedLambda resolve(SFunction<T, ?> func) {
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Class<?> clazz = func.getClass();
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String canonicalName = clazz.getCanonicalName();
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return Optional.ofNullable(FUNC_CACHE.get(canonicalName))
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.map(WeakReference::get)
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.orElseGet(() -> {
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SerializedLambda lambda = SerializedLambda.resolve(func);
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FUNC_CACHE.put(canonicalName, new WeakReference<>(lambda));
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return lambda;
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});
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}
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/**
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* 格式化 key 将传入的 key 变更为大写格式
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*
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* <pre>
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* Assert.assertEquals("USERID", formatKey("userId"))
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* </pre>
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*
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* @param key key
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* @return 大写的 key
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*/
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public static String formatKey(String key) {
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return key.toUpperCase(ENGLISH);
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}
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/**
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* 将传入的表信息加入缓存
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*
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* @param tableInfo 表信息
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*/
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public static void installCache(TableInfo tableInfo) {
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COLUMN_CACHE_MAP.put(tableInfo.getEntityType().getName(), createColumnCacheMap(tableInfo));
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}
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/**
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* 缓存实体字段 MAP 信息
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*
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* @param info 表信息
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* @return 缓存 map
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*/
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private static Map<String, ColumnCache> createColumnCacheMap(TableInfo info) {
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Map<String, ColumnCache> map = new HashMap<>();
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String kp = info.getKeyProperty();
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if (StringUtils.isNotBlank(kp)) {
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map.put(formatKey(kp), new ColumnCache(info.getKeyColumn(), info.getKeySqlSelect()));
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}
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info.getFieldList().forEach(i ->
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map.put(formatKey(i.getProperty()), new ColumnCache(i.getColumn(), i.getSqlSelect()))
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);
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return map;
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}
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/**
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* 获取实体对应字段 MAP
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*
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* @param clazz 实体类
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* @return 缓存 map
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*/
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public static Map<String, ColumnCache> getColumnMap(Class<?> clazz) {
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return COLUMN_CACHE_MAP.computeIfAbsent(clazz.getName(), key -> {
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TableInfo info = TableInfoHelper.getTableInfo(clazz);
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return info == null ? null : createColumnCacheMap(info);
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});
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}
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}
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