ULID sequence guarantee test

Author: ShanePark

projects/java/build.gradle

@@ -19,15 +19,22 @@ repositories {
 }
 
 dependencies {
+    // Lombok
+    compileOnly 'org.projectlombok:lombok:1.18.20'
+    annotationProcessor 'org.projectlombok:lombok'
+
+    // Spring Boot
     implementation 'org.springframework.boot:spring-boot-starter'
     implementation 'org.springframework.boot:spring-boot-starter-web'
-    implementation 'org.apache.commons:commons-text:1.9'
-    implementation group: 'com.opencsv', name: 'opencsv', version: '5.5.2'
     implementation 'org.springframework.boot:spring-boot-starter-test'
-    compileOnly 'org.projectlombok:lombok:1.18.20'
-    annotationProcessor 'org.projectlombok:lombok'
     implementation 'org.springframework.boot:spring-boot-starter-test'
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
+
+    // Utils
+    implementation 'org.apache.commons:commons-text:1.9'
+    implementation group: 'com.opencsv', name: 'opencsv', version: '5.5.2'
+    implementation 'com.github.f4b6a3:ulid-creator:5.2.3'
+
 }
 
 test {

projects/java/src/main/java/com/tistory/shanepark/uuid/UlidTest.java

@@ -0,0 +1,40 @@
+package com.tistory.shanepark.uuid;
+
+import com.github.f4b6a3.ulid.Ulid;
+import com.github.f4b6a3.ulid.UlidCreator;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+
+public class UlidTest {
+    static final int LOOP_COUNT = 100;
+
+    public static void main(String[] args) throws InterruptedException {
+        List<String> ulids = new ArrayList<>();
+        List<String> uuids = new ArrayList<>();
+        for (int i = 0; i < LOOP_COUNT; i++) {
+            Ulid ulid = createUlid();
+            UUID uuid = ulid.toUuid();
+            ulids.add(ulid.toString());
+            uuids.add(uuid.toString());
+            System.out.printf("ulid = %s, uuid = %s LOOP : %d/%d\n", ulid, uuid, i, LOOP_COUNT);
+            Thread.sleep(200);
+        }
+
+        // check whether those two lists are sorted
+        for (int i = 0; i < LOOP_COUNT - 1; i++) {
+            if (ulids.get(i).compareTo(ulids.get(i + 1)) > 0) {
+                throw new RuntimeException("ulid is not sorted");
+            }
+            if (uuids.get(i).compareTo(uuids.get(i + 1)) > 0) {
+                throw new RuntimeException("uuid is not sorted");
+            }
+        }
+    }
+
+    private static Ulid createUlid() {
+        return UlidCreator.getMonotonicUlid();
+    }
+
+}