[java] Comparator

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

import com.ulcjava.base.shared.internal.IllegalArgumentException;

public class ComparatorTest {
	private static final int NUM_PROJECTS = 5;
	private static final int NUM_METRICS = 3;

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		List<List<Record>> myList = new ArrayList<List<Record>>();
		Random r = new Random();

		generateNewList(myList, r);

		Collections.sort(myList, new RecordComparator(1, true));
		System.out.println(myList);
		Collections.sort(myList, new RecordComparator(1, false));
		System.out.println(myList);
		Collections.sort(myList, new RecordComparator(2, true));
		System.out.println(myList);
		Collections.sort(myList, new RecordComparator(2, false));
		System.out.println(myList);
		//so on...

	}

	private static void generateNewList(List<List<Record>> myList, Random r) {
		//now the dragon eat me for index starting at 1... ah, no, this dragon is still hunting authors of JDBC
		for (int projId = 1; projId <= NUM_PROJECTS; projId++) {
			List<Record> project = new ArrayList<Record>(10);
			for (int metricsId = 1; metricsId <= NUM_METRICS; metricsId++) {
				project.add(new Record(projId, metricsId, r.nextFloat()));
			}
			myList.add(project);
		}
	}

	public static class RecordComparator implements java.util.Comparator<List<Record>> {
		private final int metricsId;
		private final boolean ascending;

		public RecordComparator(int metricsId, boolean ascending) {
			this.metricsId = metricsId;
			this.ascending = ascending;
		}

		@Override
		public int compare(List<Record> project1, List<Record> project2) {
			int compare = Float.compare(findMetricsValue(project1, metricsId), findMetricsValue(project2, metricsId));
			if (ascending) {
				return compare;
			} else {
				return -compare;
			}
		}

		private static float findMetricsValue(List<Record> project, int metricsId) {
			for (Record oneRecord : project) {
				if (oneRecord.metrics == metricsId) {
					return oneRecord.value;
				}
			}
			throw new IllegalArgumentException("No metrics " + metricsId + "in record" + project);
		}

	}

	public static class Record {

		private final int id;
		private final int metrics;
		private final float value;

		public Record(int id, int metrics, float value) {
			this.id = id;
			this.metrics = metrics;
			this.value = value;
		}

		@Override
		public String toString() {
			return "(" + id + "," + metrics + "," + value + ")";
		}

	}

}