io.github.theangrydev.businessflows.BusinessFlow Maven / Gradle / Ivy
/*
* 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;
import java.util.Optional;
import java.util.function.Supplier;
import static java.lang.String.format;
/**
* A {@link BusinessFlow} is a biased view of a {@link BusinessCase}.
* This is the base {@link BusinessFlow} that contains operations that are common to all the biased views.
*
* @param The type of happy object this {@link BusinessFlow} may represent
* @param The type of sad object this {@link BusinessFlow} may represent
* @param The type of bias (happy, sad or technical failure) this {@link BusinessFlow} has
*/
public interface BusinessFlow extends BusinessCase {
/**
* @return A view of the underlying business case an {@link Optional} in terms of the {@link Bias}
*/
Optional toOptional();
/**
* @return If the underlying business case is the {@link Bias} then the {@link Bias}, else an {@link IllegalStateException}
* @throws IllegalStateException If the underlying business case is not the {@link Bias}
*/
default Bias get() {
return orElseThrow(() -> new IllegalStateException(format("Not present. Business case is: '%s'.", this)));
}
/**
* @param alternative The result if the underlying business case is not the {@link Bias}
* @return If the underlying business case is the {@link Bias} then the {@link Bias}, else the given alternative
*/
default Bias orElse(Bias alternative) {
return toOptional().orElse(alternative);
}
/**
* @param alternativeSupplier The supplier of the alternative result if the underlying business case is not the {@link Bias}
* @return If the underlying business case is the {@link Bias} then the {@link Bias}, else the given alternative
*/
default Bias orElseGet(Supplier alternativeSupplier) {
return toOptional().orElseGet(alternativeSupplier);
}
/**
* @param exceptionSupplier The supplier of the exception to be thrown if the underlying business case is not the {@link Bias}
* @param The type of {@link Exception} that will be thrown if the underlying business case is not the {@link Bias}
* @return If the underlying business case is the {@link Bias} then the {@link Bias}, else the given alternative
* @throws X If the underlying business case is not the {@link Bias}
*/
default Bias orElseThrow(Supplier exceptionSupplier) throws X {
return toOptional().orElseThrow(exceptionSupplier);
}
/**
* A {@link TechnicalFailure} view of the {@link BusinessFlow}.
*
* NOTE: The technical failure will only be present if the failure occurred inside of a {@link BusinessFlow}.
* To ensure failures are caught inside a flow, use e.g. {@link HappyPath#happyPathAttempt(Attempt)} at the top of
* the scope, before this method is called.
*
*
* @return A view of the underlying business case as a {@link TechnicalFailure}
*/
TechnicalFailure ifTechnicalFailure();
/**
* A {@link SadPath} view of the {@link BusinessFlow}.
*
* @return A view of the underlying business case as a {@link SadPath}
*/
SadPath ifSad();
/**
* A {@link HappyPath} view of the {@link BusinessFlow}.
*
* @return A view of the underlying business case as a {@link HappyPath}
*/
HappyPath ifHappy();
}