1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.lang3.builder;
19
20 import org.apache.commons.lang3.function.FailableSupplier;
21
22 /**
23 * Abstracts supplying an instance of {@code T}. Use to implement the builder pattern.
24 *
25 * @param <T> The type of results supplied by this supplier.
26 * @param <B> the type of builder.
27 * @param <E> The kind of thrown exception or error.
28 * @since 3.14.0
29 */
30 public abstract class AbstractSupplier<T, B extends AbstractSupplier<T, B, E>, E extends Throwable> implements FailableSupplier<T, E> {
31
32 /**
33 * Constructs a new instance.
34 */
35 public AbstractSupplier() {
36 // empty
37 }
38
39 /**
40 * Returns this instance typed as the subclass type {@code B}.
41 * <p>
42 * This is the same as the expression:
43 * </p>
44 * <pre>
45 * (B) this
46 * </pre>
47 *
48 * @return {@code this} instance typed as the subclass type {@code B}.
49 */
50 @SuppressWarnings("unchecked")
51 protected B asThis() {
52 return (B) this;
53 }
54
55 }