feat: 新增 FlexAssert 断言，强制开发者在抛出异常时指定异常信息。

mybatis-flex-core/src/main/java/com/mybatisflex/core/exception/FlexAssert.java

@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
+ *  <p>
+ *  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
+ *  <p>
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *  <p>
+ *  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 com.mybatisflex.core.exception;
+
+import java.util.Map;
+
+/**
+ * 断言。
+ *
+ * @author 王帅
+ * @since 2023-07-08
+ */
+public final class FlexAssert {
+
+    private FlexAssert() {
+    }
+
+    /**
+     * 断言对象不为空，如果为空抛出异常，并指明哪个对象为空。
+     *
+     * @param obj 对象
+     * @param msg 错误消息
+     * @throws MybatisFlexException 如果对象为空，抛出此异常。
+     */
+    public static void notNull(Object obj, String msg) {
+        if (obj == null) {
+            throw FlexExceptions.wrap(msg);
+        }
+    }
+
+    /**
+     * 断言 Map 集合不为 {@code null} 或者空集合，如果为空则抛出异常，并指明为什么不允许为空集合。
+     *
+     * @param map Map 集合
+     * @param msg 错误消息
+     * @throws MybatisFlexException 如果集合为空，抛出此异常。
+     */
+    public static void notEmpty(Map<?, ?> map, String msg) {
+        if (map == null || map.isEmpty()) {
+            throw FlexExceptions.wrap(msg);
+        }
+    }
+
+}