com.osbolab.commons.MoreEithers.java Source code

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Here is the source code for com.osbolab.commons.MoreEithers.java

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/*
 * #%L
 * Osbolab Commons
 * %%
 * Copyright (C) 2014 Osbolab LLC
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */
package com.osbolab.commons;

import com.google.common.base.Function;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;

import com.atlassian.fugue.Either;
import com.atlassian.fugue.Option;
import com.osbolab.commons.function.Effect;

/**
 * @author matt@osbolab.com (Matt Barnard)
 */
public class MoreEithers {

    public static <L, T> boolean isLeftOrEmpty(Either<L, Option<T>> from) {
        return from.isLeft() || from.right().get().isEmpty();
    }

    public static <L, T> boolean fold(Either<L, Option<T>> from, Effect<L> l, Effect<T> r) {
        if (from.isLeft()) {
            l.apply(from.left().get());
            return true;
        } else {
            if (!from.right().get().isEmpty()) {
                r.apply(from.right().get().get());
                return true;
            }
        }
        return false;
    }

    public static <L, T, R> Option<R> fold(Either<L, Option<T>> from, Function<L, R> l, Function<T, R> r) {
        if (from.isLeft()) {
            return Option.some(l.apply(from.left().get()));
        } else {
            if (!from.right().get().isEmpty()) {
                return Option.some(r.apply(from.right().get().get()));
            }
        }
        return Option.none();
    }

    public static <L, T> Either<L, Option<T>> someRight(T of) {
        return Either.right(Option.some(of));
    }

    public static <L, T> ListenableFuture<Either<L, Option<T>>> someFutureRight(T of) {
        return Futures.immediateFuture(MoreEithers.<L, T>someRight(of));
    }

    public static <L, R> ListenableFuture<Either<L, R>> futureRight(R of) {
        return Futures.immediateFuture(Either.<L, R>right(of));
    }
}