Java abstract class for sorting classes according to Algorithms fourth edition (ISBN: 978-0-321-57351-3)

BaseSort

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    Written and Copyright (C) by Corne Lukken
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
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import java.util.Comparator;
import java.util.List;

/**
 * Defined sort class standard as described in book.
 * @author Corne Lukken
 * @urk https://dantalion.nl
 */

public abstract class BaseSort<T> {
    protected List<T> list;
    protected Comparator comparator;
    
    protected long comparisons = 0;
    protected long swaps = 0;
    
    public BaseSort(List<T> list, Comparator<T> comparator) {
        this.list = list;
        this.comparator = comparator;
    }
    
    public abstract void sort();
    
    public boolean less(T a, T b) {
        comparisons++;
        return comparator.compare(a, b) < 0;
    }
    
    public void exch(int i, int j) {
        swaps++;
        T tempT = list.get(j);
        list.set(j, list.get(i));
        list.set(i, tempT);
    }
    
    public boolean isSorted() {
        for(int i = 1; i < list.size(); i++) {
            if(less(list.get(i), list.get(i-1))) return false;
        }
        return true;
    }
    
    public abstract void show();
}