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/*
 * The MIT License
 *
 * Copyright 2016-2018 Jong Soft.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.jongsoft.lang.control;

import java.util.function.Supplier;

/**
 * The OrElse interface is an extension to the {@link com.jongsoft.lang.control.Optional} interface. This interface can be used to cascade behaviour
 * when an entity is or is not present in the wrapper.
 * 
 *     For example if the {@link com.jongsoft.lang.control.Optional} has no entity contained within then the OrElse can be used to throw an exception
 *     or run alternative logic.
 * 
 * 
 * Example:
 * {@code  API.Option(null)
 *      .ifPresent(System.out::println)
 *      .elseThrow(() -> new NullPointerException("No value present"))
 * }
 *
 * @since 0.0.1
 */
public interface OrElse {

    /**
     * This operation will run when the precondition of this OrElse is not met.
     *
     * @param runner    the code to be run when the else is running
     */
    default void elseRun(Runnable runner) {}

    /**
     * This operation will create an exception using the provided {@link Supplier} and throw it.
     *
     * @param exceptionSupplier the supplier to create the exception
     * @param                the type of exception
     * @throws X                the exception in case of an OrElse run
     */
    default  void elseThrow(Supplier exceptionSupplier) throws X {}

}