Vorlesung 13 / Aufgabe 3

VL13/Aufgabe03/Aufgabe03.java

@@ -0,0 +1,135 @@
+package VL13.Aufgabe03;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.Random;
+
+/**
+ * Vorlesung 13 / Aufgabe 3
+ *
+ * @author Sebastian Brosch
+ */
+public class Aufgabe03 {
+  public static void main(String[] args) {
+    final int MAX_RUNS = 10;
+    int[] sizes = { 10000, 20000, 50000, 100000, 200000, 500000, 1000000, 2000000, 5000000, 10000000, 20000000,
+        50000000 };
+
+    for (int size : sizes) {
+      long sumArrayList = 0;
+      long sumLinkedList = 0;
+
+      for (int i = 0; i < MAX_RUNS; i++) {
+        ArrayList<String> values = getValues(size);
+        sumArrayList += runTestArrayList(values);
+        sumLinkedList += runTestLinkedList(values);
+      }
+
+      System.out.printf("\nMittelwert (Zeichenketten: %,d):\n", size);
+      System.out.printf("  ArrayList: %d Millisekunden\n", (sumArrayList / MAX_RUNS));
+      System.out.printf("  LinkedList: %d Millisekunden\n", (sumLinkedList / MAX_RUNS));
+    }
+
+    System.out.println("\nAlle Tests wurden beendet.");
+  }
+
+  /**
+   * Method to run a test using a ArrayList.
+   *
+   * @param values The values to fill in ArrayList.
+   * @return The elapsed time of the test.
+   */
+  private static long runTestArrayList(ArrayList<String> values) {
+    long timeStart = System.currentTimeMillis();
+    ArrayList<String> testArrayList = new ArrayList<String>();
+
+    for (String value : values) {
+      testArrayList.add(value);
+    }
+
+    return System.currentTimeMillis() - timeStart;
+  }
+
+  /**
+   * Method to run a test using LinkedList.
+   *
+   * @param values The values to fill in LinkedList.
+   * @return The elapsed time of the test.
+   */
+  private static long runTestLinkedList(ArrayList<String> values) {
+    long timeStart = System.currentTimeMillis();
+    LinkedList<String> testLinkedList = new LinkedList<String>();
+
+    for (String value : values) {
+      testLinkedList.add(value);
+    }
+
+    return System.currentTimeMillis() - timeStart;
+  }
+
+  /**
+   * Method to determine a random number from a certain range.
+   *
+   * @param start The first number of the range.
+   * @param end   The last number of the range.
+   * @return A random number from a certain range.
+   */
+  private static int getRandomNumber(int start, int end) {
+    return (new Random()).nextInt((end - start + 1)) + start;
+  }
+
+  /**
+   * Method to generate a random string.
+   *
+   * @param min The minimum length of the random string.
+   * @param max The maximum length of the random string.
+   * @return A random string.
+   */
+  private static String getRandomString(int min, int max) {
+    final String NUMBERS = "0123456789";
+    final String UCHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    final String LCHARS = UCHARS.toLowerCase();
+
+    String random = "";
+    int length = getRandomNumber(min, max);
+
+    for (int i = 0; i < length; i++) {
+      String chars = "";
+
+      switch (getRandomNumber(1, 3)) {
+        case 1:
+          chars = NUMBERS;
+          break;
+        case 2:
+          chars = UCHARS;
+          break;
+        case 3:
+          chars = LCHARS;
+          break;
+      }
+
+      int charIndex = getRandomNumber(0, chars.length() - 1);
+      random += chars.substring(charIndex, charIndex + 1);
+    }
+
+    return random;
+  }
+
+  /**
+   * Method to get a list with random strings.
+   *
+   * @param numberOfStrings The amount of random strings to generate.
+   * @return A list with random strings.
+   */
+  private static ArrayList<String> getValues(int numberOfStrings) {
+    final int MIN_LENGTH = 10;
+    final int MAX_LENGTH = 16;
+    ArrayList<String> values = new ArrayList<String>();
+
+    for (int i = 0; i < numberOfStrings; i++) {
+      values.add(getRandomString(MIN_LENGTH, MAX_LENGTH));
+    }
+
+    return values;
+  }
+}