1 /*
2 * Copyright 2016-2025 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.mybatis.dynamic.sql.select.aggregate;
17
18 import java.util.Optional;
19
20 import org.jspecify.annotations.Nullable;
21 import org.mybatis.dynamic.sql.BindableColumn;
22
23 /**
24 * Count functions are implemented differently than the other aggregates. This is primarily to preserve
25 * backwards compatibility. Count functions are configured as BindableColumns of type Long
26 * as it is assumed that the count functions always return a number.
27 */
28 public abstract class AbstractCount implements BindableColumn<Long> {
29 private final @Nullable String alias;
30
31 protected AbstractCount() {
32 this(null);
33 }
34
35 protected AbstractCount(@Nullable String alias) {
36 this.alias = alias;
37 }
38
39 @Override
40 public Optional<String> alias() {
41 return Optional.ofNullable(alias);
42 }
43 }