org.kohsuke.stapler.Optional Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of stapler-core Show documentation

Stapler HTTP request handling engine

The newest version!

/*
 * Copyright (c) 2004-2010, Kohsuke Kawaguchi
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided
 * that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice, this list of
 *       conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.kohsuke.stapler;

/**
 * Represents a T value or no value at all. Used to work around the lack of null value in the computing map.
 *
 * @author Kohsuke Kawaguchi
 */
final class Optional {
    private final T value;

    Optional(T value) {
        this.value = value;
    }

    public T get() { return value; }


    private static Optional NONE = new Optional(null);

    public static  Optional none() {
        return NONE;
    }

    public static  Optional create(T value) {
        if (value==null)    return NONE;    // cache
        return new Optional(value);
    }
}