/*
* Data Hub Service (DHuS) - For Space data distribution.
* Copyright (C) 2016 GAEL Systems
*
* This file is part of DHuS software sources.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package fr.gael.dhus.util.functional;
import org.apache.commons.collections4.Transformer;
/**
* Usefull Utilities for the Java functional programming package.
*/
public class FunctionalTools
{
/**
* Compose 2 Transformers into 1.
* @param <A> Input type.
* @param <B> Transition type.
* @param <C> Output type.
* @param first firstly invoked Transformer.
* @param second secondly invoked Transformer.
* @return {@code second.transform(first.transform(A))}.
*/
public static <A,B,C> Transformer<A,C> compose(Transformer<A,B> first,
Transformer<? super B,C> second)
{
final Transformer<A,B> ffirst = first;
final Transformer<? super B,C> fsecond = second;
return new Transformer<A,C>()
{
@Override
public C transform(A u)
{
return fsecond.transform(ffirst.transform(u));
}
};
}
}