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Basic utilities to compensate shortcomings of Java SE. Part of chicory.
There is a newer version: 0.36
/*
 * Copyright (c) 2014, Victor Nazarov 
 * 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.
 *     * Neither the name of the Victor Nazarov nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * 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  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 com.github.sviperll;

import java.util.NoSuchElementException;

public class OptionalVisitors {
    public static  OptionalVisitor throwNoSuchElementException() {
        return new OptionalVisitor() {
            @Override
            public T present(T value) throws NoSuchElementException {
                return value;
            }

            @Override
            public T missing() throws NoSuchElementException {
                throw new NoSuchElementException();
            }
        };
    }

    public static  OptionalVisitor returnNull() {
        return new OptionalVisitor() {
            @Override
            public T present(T value) throws RuntimeException {
                return value;
            }

            @Override
            public T missing() throws RuntimeException {
                return null;
            }
        };
    }

    public static  OptionalVisitor returnDefault(final T defaultValue) {
        return new OptionalVisitor() {
            @Override
            public T present(T value) throws RuntimeException {
                return value;
            }

            @Override
            public T missing() throws RuntimeException {
                return defaultValue;
            }
        };
    }

    private OptionalVisitors() {
    }
}