    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      https://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.lang3.builder;
    019
    020import org.apache.commons.lang3.function.FailableSupplier;
    021
    022/**
    023 * Abstracts supplying an instance of {@code T}. Use to implement the builder pattern.
    024 *
    025 * @param <T> The type of results supplied by this supplier.
    026 * @param <B> the type of builder.
    027 * @param <E> The kind of thrown exception or error.
    028 * @since 3.14.0
    029 */
    030public abstract class AbstractSupplier<T, B extends AbstractSupplier<T, B, E>, E extends Throwable> implements FailableSupplier<T, E> {
    031
    032    /**
    033     * Constructs a new instance.
    034     */
    035    public AbstractSupplier() {
    036        // empty
    037    }
    038
    039    /**
    040     * Returns this instance typed as the subclass type {@code B}.
    041     * <p>
    042     * This is the same as the expression:
    043     * </p>
    044     * <pre>
    045     * (B) this
    046     * </pre>
    047     *
    048     * @return {@code this} instance typed as the subclass type {@code B}.
    049     */
    050    @SuppressWarnings("unchecked")
    051    protected B asThis() {
    052        return (B) this;
    053    }
    054
    055}