添加注释。

src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalLongFunction.java

@@ -1,8 +1,35 @@
+/*
+ * Copyright 2022-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 xyz.zhouxy.plusone.commons.function;
 
 import java.util.OptionalLong;
 import java.util.function.Function;
 
+/**
+ * ToOptionalLongFunction
+ *
+ * <p>
+ * 接受类型为 T 的参数，返回 {@link OptionalLong} 对象。
+ *
+ * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
+ * @since 0.1.0
+ * @see OptionalLong
+ * @see Function
+ */
 @FunctionalInterface
 public interface ToOptionalLongFunction<T> extends Function<T, OptionalLong> {
 }