/**
 * B+ Tree Test Method.
 * 
 * @category Architecture of DBMS WS 06/07 - Assignment
 * @author DBIS, University of Konstanz
 */
public final class Test {
  /** Random instance with initial seed to guarantee constant random numbers. */
  private static final java.util.Random RANDOM = new java.util.Random(1);
  /** Timer, used for performance measuring. */
  private static long time;

  /**
   * Main method, user for testing.
   * @param args command line arguments (ignored)
   */
  public static void main(String[] args) {
    out("*** B+Tree Testing ***\n\n");

    /** Test simple string array. */
    test(new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 });

    /** Test random string array. */
    //test(randomValues(100));
    //test(randomValues(10000));
    //test(randomValues(1000000));

    out("*** Finished Testing ***\n");
  }
    
  /**
   * Create and test a B+ Tree with the specified values.
   * @param values values to be inserted and tested
   */
  public static void test(int[] values) {
    // number of strings to be inserted
    int nrValues = values.length;

    // initialize timer
    time = System.nanoTime();

    out("Create B+ Tree with " + nrValues + " Values...\n");
    BTree tree = new BTree();
    mem();

    out("Insert Values...\n");
    for(int v : values) tree.insert(v);
    int size = tree.nrValues();
    out("Stored Nodes: " + size + "\n");
    mem();

    out("Finding Values...\n");
    int found = 0;
    for(int v : values) if(tree.contains(v)) found++;
    out(found + " found, " + nrValues + " expected.\n");
    mem();

    out("Reinsert Values... \n");
    for(int v : values) tree.insert(v);
    out(tree.nrValues() + " stored, " + size + " expected.\n");
    mem();

    out("Finding Values...\n");
    found = 0;
    for(int v : values) if(tree.contains(v)) found++;
    out(found + " found, " + nrValues + " expected.\n");
    mem();

    out("\n");
  }

  /**
   * Creates an array with random strings.
   * @param n number of random strings
   * @return random string
   */
  private static int[] randomValues(int n) {
    int[] strings = new int[n];
    for(int i = 0; i < n; i++) strings[i] = RANDOM.nextInt() & 65535;
    return strings;
  }

  /**
   * Displays some timing and approximate memory info.
   */
  public static void mem() {
    // display timing information
    out("- Time: " + (System.nanoTime() - time) / 1000000 + " ms");

    // initialize memory and calculate memory consumption
    for(int i = 0; i < 3; i++) System.gc();
    Runtime r = Runtime.getRuntime();
    long a = r.totalMemory() - r.freeMemory();
    boolean b = a > 1 << 20;
    long f = b ? 20 : 10;
    out(" (" + (a + (1 << f - 1) >> f) + (b ? " mb" : " kb") + ")\n\n");

    // set new timer
    time = System.nanoTime();
  }

  /**
   * Prints the specified text to {@link System#out}.
   * @param text text to be printed
   */
  private static void out(String text) {
    System.out.print(text);
  }
}