001/**
002 * The MIT License (MIT)
003 *
004 * Copyright (c) 2018 nobark (tools4j), Marco Terzer, Anton Anufriev
005 *
006 * Permission is hereby granted, free of charge, to any person obtaining a copy
007 * of this software and associated documentation files (the "Software"), to deal
008 * in the Software without restriction, including without limitation the rights
009 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010 * copies of the Software, and to permit persons to whom the Software is
011 * furnished to do so, subject to the following conditions:
012 *
013 * The above copyright notice and this permission notice shall be included in all
014 * copies or substantial portions of the Software.
015 *
016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
022 * SOFTWARE.
023 */
024package org.tools4j.nobark.loop;
025
026/**
027 * Handler for unexpected exceptions thrown by a {@link Step} in a {@link Loop}.
028 */
029@FunctionalInterface
030public interface ExceptionHandler {
031
032    /**
033     * Handles an unexpected exception that was thrown by the given {@code step} that is part of the given {@code loop}.
034     *
035     * @param loop      the loop which the failed step is part of
036     * @param step      the step that throws the specified exception
037     * @param throwable the exception thrown by step
038     */
039    void handleException(Loop loop, Step step, Throwable throwable);
040
041    /**
042     * {@link Step#perform() Performs} the step's method handling possible exceptions by invoking this handler's
043     * {@link #handleException(Loop, Step, Throwable)} method.
044     *
045     * @param loop the loop to which the step belongs
046     * @param step the step to perform
047     * @return true if work was performed by the step, and false otherwise or if an exception was caught
048     */
049    default boolean performQuietly(final Loop loop, final Step step) {
050        try {
051            return step.perform();
052        } catch (final Throwable t) {
053            handleException(loop, step, t);
054            return false;
055        }
056    }
057}