com.github.jeluard.guayaba.base.Optionals.java Source code

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Here is the source code for com.github.jeluard.guayaba.base.Optionals.java

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/**
 * Copyright 2012 Julien Eluard
 * This project includes software developed by Julien Eluard: https://github.com/jeluard/
 *
 * 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 com.github.jeluard.guayaba.base;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;

/**
 * Helper methods for {@link Optional}.
 */
public final class Optionals {

    private Optionals() {
    }

    /**
     * @param <T>
     * @param optional
     * @return an {@link Optional} returning encapsulated {@link Optional}
     */
    public static <T> Optional<T> flatten(final Optional<Optional<T>> optional) {
        Preconditions.checkNotNull(optional, "null optional");

        if (!optional.isPresent()) {
            return Optional.absent();
        }

        return optional.get();
    }

}