SortingTest.java

/* ************************************************
 * Classe per testare gli algoritmi di ordinamento.
 *
 * Esempio di esecuzione::
 *
 * java SortingTest file selectionsort
 *
 * dove "file" è il nome di un file contenente interi
 * e selectionsort è uno degli algoritmi di ordinamento
 * fornini dalla classe Sorting.
 *
 * Attenzione: l'algoritmo quicksort potrebbe causare
 * stack overflow. In tal caso, modificare la dimensione
 * dello stack della JVM con il seguente comando:
 *
 * java -Xss20m SortingTest file quicksort
 *
 * *************************************************/

import java.util.Arrays;
import java.util.ArrayList;
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.lang.reflect.Method;


import algorithm.sorting.Sorting;


public class SortingTest {

    private static int[] readarray(String filename) throws FileNotFoundException {
        ArrayList<Integer> L = new ArrayList<Integer>();
        Scanner input        = new Scanner(new File(filename));
        while(input.hasNext()) 
            L.add(input.nextInt());
        
        
        return L.stream().mapToInt(Integer::intValue).toArray();
    }

    private static int[] savesorted(int A[]) {
        int[] B = A.clone();
        Arrays.sort(B);
        return B;
    } 

    private static boolean issorted(int A[], int B[]) {
        for(int i = 0; i < A.length-1; i++)
            if(A[i] != B[i])
                return false;
        return true;
    }

    public static void main(String args[]) {
        Sorting S   = new Sorting();
        Method  M   = null;
        int     A[] = null;
        int     B[] = null;

        
        if(args.length != 2) {
            
            System.err.println("Usage: SortingTest <filename> <sorting algorithm>\n");
            System.err.println("Sorting algorithms:");
            for (Method m : S.getClass().getMethods()) {
                if (m.getDeclaringClass() == S.getClass() && m.getParameterTypes()[0].equals(int[].class))
                    System.err.println("- " + m.getName());
            }
            System.exit(0);
        }

        try {
            M = S.getClass().getDeclaredMethod(args[1],int[].class);
        } catch(Exception e) {
            System.out.println(e.toString());
            System.exit(1);
        }

        try {
            A = readarray(args[0]);
            B = savesorted(A);
        } catch(Exception e) {
            System.out.println(e.toString());
            System.exit(1);
        }

        try {
            long start = System.currentTimeMillis();
            M.invoke(S,A);
            long end  = System.currentTimeMillis();
            //System.out.println(Arrays.toString(A)); 
            System.out.println("Algorithm: " + args[1] + "    \tTime: " + (end-start)/1000.0 +  "s " + (issorted(A,B) ? "[SORTED]" : "[UNSORTED]"));
        } catch(Exception e) {
            e.printStackTrace();
            System.exit(1);
        }

    }
    
}