Merge pull request #3179 from egoebelbecker/master

BAEL-1374 - search an array

core-java/src/test/java/com/baeldung/array/SearchArrayTest.java

@@ -0,0 +1,116 @@
+package com.baeldung.array;
+
+import org.junit.Test;
+
+import java.util.*;
+
+public class SearchArrayTest {
+
+
+    @Test
+    public void searchArrayAllocNewCollections() {
+
+        int count = 1000;
+
+        String[] strings = seedArray(count);
+
+        long startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            searchList(strings, "W");
+        }
+        long duration = System.nanoTime() - startTime;
+        System.out.println("SearchList:  " + duration / 10000);
+
+        startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            searchSet(strings,"S");
+        }
+        duration = System.nanoTime() - startTime;
+        System.out.println("SearchSet:  " + duration / 10000);
+
+        startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            searchLoop(strings, "T");
+        }
+        duration = System.nanoTime() - startTime;
+        System.out.println("SearchLoop:  " + duration / 10000);
+    }
+
+    @Test
+    public void searchArrayReuseCollections() {
+
+        int count = 10000;
+        String[] strings = seedArray(count);
+
+        List<String> asList = Arrays.asList(strings);
+        Set<String> asSet = new HashSet<>(Arrays.asList(strings));
+
+        long startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            asList.contains("W");
+        }
+        long duration = System.nanoTime() - startTime;
+        System.out.println("List:  " + duration / 10000);
+
+        startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            asSet.contains("S");
+        }
+        duration = System.nanoTime() - startTime;
+        System.out.println("Set:  " + duration / 10000);
+
+        startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            searchLoop(strings, "T");
+        }
+        duration = System.nanoTime() - startTime;
+        System.out.println("Loop:  " + duration / 10000);
+
+    }
+
+
+    @Test
+    public void searchArrayBinarySearch() {
+
+        int count = 10000;
+        String[] strings = seedArray(count);
+        Arrays.sort(strings);
+
+        long startTime = System.nanoTime();
+        for (int i = 0; i < count; i++) {
+            Arrays.binarySearch(strings, "A");
+        }
+        long duration = System.nanoTime() - startTime;
+        System.out.println("Binary search:  " + duration / 10000);
+
+    }
+
+    private boolean searchList(String[] strings, String searchString) {
+      return Arrays.asList(strings).contains(searchString);
+  }
+
+    private boolean searchSet(String[] strings, String searchString) {
+        Set<String> set = new HashSet<>(Arrays.asList(strings));
+        return set.contains(searchString);
+    }
+
+    private boolean searchLoop(String[] strings, String searchString) {
+        for (String s : strings) {
+            if (s.equals(searchString))
+            return true;
+        }
+        return false;
+    }
+
+    private String[] seedArray(int length) {
+
+        String[] strings = new String[length];
+        Random random = new Random();
+        for (int i = 0; i < length; i++)
+        {
+            strings[i] = String.valueOf(random.nextInt());
+        }
+        return strings;
+    }
+
+}