[Update] remove hashCode, add nano & secure

core-java-modules/core-java-uuid/src/test/java/com/baeldung/uuid/UUIDPositiveLongGeneratorUnitTest.java

@@ -1,52 +1,43 @@
 package com.baeldung.uuid;
 
 import org.junit.jupiter.api.Test;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.lang.reflect.Method;
-import java.text.DecimalFormat;
 import java.util.HashSet;
 import java.util.Set;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class UUIDPositiveLongGeneratorUnitTest {
-    private final static int NUMBER_OF_CHECKS = 1000000;
-    private final static double COLLISION_THRESHOLD = 0.001;
+
     private final UUIDPositiveLongGenerator uuidLongGenerator = new UUIDPositiveLongGenerator();
-    private final Logger logger = LoggerFactory.getLogger(UUIDPositiveLongGeneratorUnitTest.class);
+
+    private final Set<Long> uniqueValues = new HashSet<>();
 
     @Test
-    void whenForeachGenerateLongValue_thenCollisionsCheck() throws Exception {
-        printTableHeader();
+    void whenForeachMethods_thenRetryWhileNotUnique() throws Exception {
         for (Method method : uuidLongGenerator.getClass().getDeclaredMethods()) {
-            collisionCheck(method);
-        }
-    }
-
-    private void printTableHeader() {
-        logger.info(String.format("%-30s %-15s %-15s", "Approach(method name)", "collisions", "probability"));
-        logger.info("-----------------------------------------------------------------------");
-    }
-
-    private void printOutput(String method, int collisionsCount, double collisionsProbability) {
-        DecimalFormat decimalFormat = new DecimalFormat("#.#####");
-        logger.info(String.format("%-30s %-15s %-15s", method, collisionsCount, decimalFormat.format(collisionsProbability)));
-    }
-
-    private void collisionCheck(Method method) throws Exception {
-        Set<Long> uniqueValues = new HashSet<>();
-        int collisions = 0;
-        for (int i = 0; i < NUMBER_OF_CHECKS; i++) {
-            long uniqueValue = (long) method.invoke(uuidLongGenerator);
+            long uniqueValue;
+            do uniqueValue = (long) method.invoke(uuidLongGenerator); while (!isUnique(uniqueValue));
             assertThat(uniqueValue).isPositive();
-            if (!uniqueValues.add(uniqueValue)) {
-                collisions++;
-            }
         }
-        double collisionsProbability = (double) collisions / NUMBER_OF_CHECKS;
-        printOutput(method.getName(), collisions, collisionsProbability);
-        assertThat(collisionsProbability).isLessThan(COLLISION_THRESHOLD);
     }
+
+    @Test
+    void whenGivenLongValue_thenCheckUniqueness() {
+        long uniqueValue = generateUniqueLong();
+        assertThat(uniqueValue).isPositive();
+    }
+
+    private long generateUniqueLong() {
+        long uniqueValue;
+        do uniqueValue = uuidLongGenerator.combineBitwise(); while (!isUnique(uniqueValue));
+        return uniqueValue;
+    }
+
+    private boolean isUnique(long value) {
+        // Implement uniqueness checking logic, for example, by checking in the database
+        return uniqueValues.add(value);
+    }
+
 }