feat: use monotonic ulid behavior

Signed-off-by: Matheus Cruz <[email protected]>

Author: mcruzdev

impl/core/src/main/java/io/serverlessworkflow/impl/UlidWorkflowInstanceIdFactory.java renamed to impl/core/src/main/java/io/serverlessworkflow/impl/MonotonicUlidWorkflowInstanceIdFactory.java

@@ -19,15 +19,22 @@
 import java.security.SecureRandom;
 
 /**
- * A {@link WorkflowInstanceIdFactory} implementation that generates ULIDs as workflow instance IDs.
+ * A {@link WorkflowInstanceIdFactory} implementation that generates Monotonic ULIDs as workflow
+ * instance IDs.
  */
-public class UlidWorkflowInstanceIdFactory implements WorkflowInstanceIdFactory {
+public class MonotonicUlidWorkflowInstanceIdFactory implements WorkflowInstanceIdFactory {
 
   private final SecureRandom random = new SecureRandom();
   private final ULID ulid = new ULID(random);
+  private ULID.Value previousUlid;
 
   @Override
-  public String get() {
-    return ulid.nextULID();
+  public synchronized String get() {
+    if (previousUlid == null) {
+      previousUlid = ulid.nextValue();
+    } else {
+      previousUlid = ulid.nextMonotonicValue(previousUlid);
+    }
+    return previousUlid.toString();
   }
 }

impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowApplication.java

@@ -140,7 +140,7 @@ public SchemaValidator getValidator(SchemaInline inline) {
     private ResourceLoaderFactory resourceLoaderFactory = DefaultResourceLoaderFactory.get();
     private SchemaValidatorFactory schemaValidatorFactory;
     private WorkflowPositionFactory positionFactory = () -> new QueueWorkflowPosition();
-    private WorkflowInstanceIdFactory idFactory = new UlidWorkflowInstanceIdFactory();
+    private WorkflowInstanceIdFactory idFactory = new MonotonicUlidWorkflowInstanceIdFactory();
     private ExecutorServiceFactory executorFactory = new DefaultExecutorServiceFactory();
     private EventConsumer<?, ?> eventConsumer;
     private Collection<EventPublisher> eventPublishers = new ArrayList<>();