https://github.com/eclipse/eclipse-collections/eclipse-collections: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar 
/*
 * Copyright (c) 2016 Goldman Sachs.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompany this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */

package org.eclipse.collections.impl.block.function;

import org.eclipse.collections.api.block.function.Function2;

public final class MultiplyFunction
{
    public static final Function2<Integer, Integer, Integer> INTEGER = new MultiplyIntegerFunction();
    public static final Function2<Double, Double, Double> DOUBLE = new MultiplyDoubleFunction();
    public static final Function2<Long, Long, Long> LONG = new MultiplyLongFunction();

    private MultiplyFunction()
    {
        throw new AssertionError("Suppress default constructor for noninstantiability");
    }

    private static class MultiplyIntegerFunction implements Function2<Integer, Integer, Integer>
    {
        private static final long serialVersionUID = 1L;

        @Override
        public Integer value(Integer argument1, Integer argument2)
        {
            return argument1 * argument2;
        }
    }

    private static class MultiplyDoubleFunction implements Function2<Double, Double, Double>
    {
        private static final long serialVersionUID = 1L;

        @Override
        public Double value(Double argument1, Double argument2)
        {
            return argument1 * argument2;
        }
    }

    private static class MultiplyLongFunction implements Function2<Long, Long, Long>
    {
        private static final long serialVersionUID = 1L;

        @Override
        public Long value(Long argument1, Long argument2)
        {
            return argument1 * argument2;
        }
    }
}