io.github.theangrydev.businessflows.PotentialFailure Maven / Gradle / Ivy

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/*
 * Copyright 2016 Liam Williams .
 *
 * This file is part of business-flows.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.github.theangrydev.businessflows;

/**
 * This type represents a failure that may occur in e.g. {@link HappyPath#attempt(ActionThatMightFail)}.
 *
 * @param  The type of sad object that represents a failure
 */
public interface PotentialFailure extends WithOptional {

    /**
     * Construct a known failure that is mapped to a {@link Sad} object.
     *
     * @param sad   The sad object that represents a failure
     * @param  The type of sad object that represents a failure
     * @return A {@link PotentialFailure} that represents a failure
     */
    static  PotentialFailure failure(Sad sad) {
        return new PotentialFailureFailure<>(sad);
    }

    /**
     * Construct a known success.
     *
     * @param  The type of sad object that represents a failure
     * @return A {@link PotentialFailure} that represents a success
     */
    static  PotentialFailure success() {
        return new PotentialFailureSuccess<>();
    }

    /**
     * Convert the {@link PotentialFailure} to a {@link HappyPath}.
     *
     * @param happy   The happy object the {@link PotentialFailure} is about
     * @param  The type of the happy object the {@link PotentialFailure} is about
     * @return A {@link HappyPath} that is happy if the {@link PotentialFailure} is a {@link PotentialFailure#success()}
     * or sad inside if the {@link PotentialFailure} is a {@link PotentialFailure#failure(Object)}
     */
     HappyPath toHappyPath(Happy happy);
}