org.gradle.internal.Either Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of gradle-api Show documentation

Gradle 6.9.1 API redistribution.

There is a newer version: 8.11.1

/*
 * Copyright 2021 the original author or authors.
 *
 * 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 org.gradle.internal;

import java.util.function.Function;

import static org.gradle.internal.Cast.uncheckedCast;

/**
 * Represents values with two possibilities.
 *
 * @param  the left type.
 * @param  the right type.
 */
public abstract class Either {

    public static  Either left(L value) {
        return new Left<>(value);
    }

    public static  Either right(R value) {
        return new Right<>(value);
    }

    public abstract  U fold(Function l, Function r);

    public abstract  Either map(Function r);

    private static class Left extends Either {
        private final L value;

        public Left(L value) {
            this.value = value;
        }

        @Override
        public  U fold(Function l, Function r) {
            return l.apply(value);
        }

        @Override
        public  Either map(Function r) {
            return uncheckedCast(this);
        }
    }

    private static class Right extends Either {
        private final R value;

        public Right(R value) {
            this.value = value;
        }

        @Override
        public  U fold(Function l, Function r) {
            return r.apply(value);
        }

        @Override
        public  Either map(Function r) {
            return new Right<>(r.apply(value));
        }
    }
}