net.sf.gluebooster.java.booster.basic.container.ContainerBoostUtilsBasic Maven / Gradle / Ivy

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package net.sf.gluebooster.java.booster.basic.container;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import net.sf.gluebooster.java.booster.essentials.meta.BoostedComparator;
import net.sf.gluebooster.java.booster.essentials.utils.ContainerBoostUtils;

/**
 * Additional container boost utils.
 * 
 * @author cbauer
 *
 */
public class ContainerBoostUtilsBasic extends ContainerBoostUtils {

	/**
	 * Sorts a list using a comparator.
	 * 
	 * @param list
	 *            the list to be modified
	 * @param comparator
	 *            there may be only a partial ordering
	 */
	public static  void sortPartialOrderedList(List list, Comparator comparator) {
		try {
			Collections.sort(list, comparator);
		} catch (Exception orderingProblemException) {
			if (comparator instanceof BoostedComparator) {
				ArrayList result = new ArrayList(list.size());
				ArrayList changingList = new ArrayList(list);
				// try to get a partial ordering.
				while (!changingList.isEmpty()) {
					Element minimum = getMinimum(changingList, comparator);
					result.add(minimum);
					changingList.remove(minimum);
				}

				// check the ordering (easy check)
				for (int i = result.size() - 1; i > 0; i--) {
					Element element1 = result.get(i - 1);
					Element element2 = result.get(i);
					Integer comparison = ComparatorBoostUtils.compare(element1, element2, comparator);
					if (comparison != null && comparison.intValue() > 0) {
						ComparatorBoostUtils.compare(element1, element2, comparator);
						throw new IllegalStateException("could not order list because " + element1 + " should not be greater than " + element2);
					}
				}

				list.clear();
				list.addAll(result);

			} else {
				throw orderingProblemException;
			}
		}
	}


}