largeRCRF-Java/src/main/java/ca/joeltherrien/randomforest/Bootstrapper.java

/*
 * Copyright (c) 2019 Joel Therrien.
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU 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 General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package ca.joeltherrien.randomforest;

import lombok.RequiredArgsConstructor;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

@RequiredArgsConstructor
public class Bootstrapper<T> {

    final private List<T> originalData;

    public List<T> bootstrap(Random random){
        final int n = originalData.size();

        final List<T> newList = new ArrayList<>(n);

        for(int i=0; i<n; i++){
            final int index = random.nextInt(n);

            newList.add(originalData.get(index));
        }

        return newList;

    }

}