serverlessworkflow · fjtirado · Aug 13, 2025 · Aug 13, 2025
@@ -61,7 +61,8 @@ public abstract class AbstractTaskExecutor<T extends TaskBase> implements TaskEx
   private final Optional<SchemaValidator> contextSchemaValidator;
   private final Optional<WorkflowPredicate> ifFilter;
 
-  public abstract static class AbstractTaskExecutorBuilder<T extends TaskBase>
+  public abstract static class AbstractTaskExecutorBuilder<
+          T extends TaskBase, V extends AbstractTaskExecutor<T>>
       implements TaskExecutorBuilder<T> {
     private Optional<WorkflowFilter> inputProcessor = Optional.empty();
     private Optional<WorkflowFilter> outputProcessor = Optional.empty();
@@ -77,7 +78,7 @@ public abstract static class AbstractTaskExecutorBuilder<T extends TaskBase>
     protected final Workflow workflow;
     protected final ResourceLoader resourceLoader;
 
-    private TaskExecutor<T> instance;
+    private V instance;
 
     protected AbstractTaskExecutorBuilder(
         WorkflowMutablePosition position,
@@ -145,17 +146,20 @@ private TaskExecutorBuilder<?> next(Map<String, TaskExecutorBuilder<?>> connecti
       return next;
     }
 
-    public TaskExecutor<T> build() {
+    public V build() {
       if (instance == null) {
         instance = buildInstance();
+        buildTransition(instance);
       }
       return instance;
     }
 
-    protected abstract TaskExecutor<T> buildInstance();
+    protected abstract V buildInstance();
+
+    protected abstract void buildTransition(V instance);
   }
 
-  protected AbstractTaskExecutor(AbstractTaskExecutorBuilder<T> builder) {
+  protected AbstractTaskExecutor(AbstractTaskExecutorBuilder<T, ?> builder) {
     this.task = builder.task;
     this.taskName = builder.taskName;
     this.position = builder.position;

@@ -46,7 +46,7 @@ protected CallTaskExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<T> buildInstance() {
+    public CallTaskExecutor<T> buildInstance() {
       return new CallTaskExecutor<>(this);
     }
   }

@@ -46,7 +46,7 @@ protected DoExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<DoTask> buildInstance() {
+    public DoExecutor buildInstance() {
       return new DoExecutor(this);
     }
   }

@@ -61,7 +61,7 @@ protected EmitExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<EmitTask> buildInstance() {
+    public EmitExecutor buildInstance() {
       return new EmitExecutor(this);
     }
   }

@@ -68,7 +68,7 @@ protected WorkflowValueResolver<Collection<?>> buildCollectionFilter() {
     }
 
     @Override
-    public TaskExecutor<ForTask> buildInstance() {
+    public ForExecutor buildInstance() {
       return new ForExecutor(this);
     }
   }

@@ -62,7 +62,7 @@ protected ForkExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<ForkTask> buildInstance() {
+    public ForkExecutor buildInstance() {
       return new ForkExecutor(this);
     }
   }

@@ -155,7 +155,7 @@ private EventRegistrationBuilder from(EventFilter filter) {
     }
 
     @Override
-    public TaskExecutor<ListenTask> buildInstance() {
+    public ListenExecutor buildInstance() {
       return registrations.isAnd() ? new AndListenExecutor(this) : new OrListenExecutor(this);
     }
   }

@@ -114,7 +114,7 @@ private Error findError(String raiseErrorReference) {
     }
 
     @Override
-    public TaskExecutor<RaiseTask> buildInstance() {
+    public RaiseExecutor buildInstance() {
       return new RaiseExecutor(this);
     }
   }

@@ -28,15 +28,14 @@
 
 public abstract class RegularTaskExecutor<T extends TaskBase> extends AbstractTaskExecutor<T> {
 
-  protected final TransitionInfo transition;
+  protected TransitionInfo transition;
 
   protected RegularTaskExecutor(RegularTaskExecutorBuilder<T> builder) {
     super(builder);
-    this.transition = TransitionInfo.build(builder.transition);
   }
 
   public abstract static class RegularTaskExecutorBuilder<T extends TaskBase>
-      extends AbstractTaskExecutorBuilder<T> {
+      extends AbstractTaskExecutorBuilder<T, RegularTaskExecutor<T>> {
 
     private TransitionInfoBuilder transition;
 
@@ -52,6 +51,11 @@ protected RegularTaskExecutorBuilder(
     public void connect(Map<String, TaskExecutorBuilder<?>> connections) {
       this.transition = next(task.getThen(), connections);
     }
+
+    @Override
+    protected void buildTransition(RegularTaskExecutor<T> instance) {
+      instance.transition = TransitionInfo.build(transition);
+    }
   }
 
   @Override

@@ -54,7 +54,7 @@ protected SetExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<SetTask> buildInstance() {
+    public SetExecutor buildInstance() {
       return new SetExecutor(this);
     }
   }

@@ -39,7 +39,8 @@ public class SwitchExecutor extends AbstractTaskExecutor<SwitchTask> {
   private final Map<WorkflowPredicate, TransitionInfo> workflowFilters;
   private final TransitionInfo defaultTask;
 
-  public static class SwitchExecutorBuilder extends AbstractTaskExecutorBuilder<SwitchTask> {
+  public static class SwitchExecutorBuilder
+      extends AbstractTaskExecutorBuilder<SwitchTask, SwitchExecutor> {
     private final Map<SwitchCase, WorkflowPredicate> workflowFilters = new HashMap<>();
     private Map<WorkflowPredicate, TransitionInfoBuilder> switchFilters = new HashMap<>();
     private FlowDirective defaultDirective;
@@ -77,9 +78,12 @@ public void connect(Map<String, TaskExecutorBuilder<?>> connections) {
     }
 
     @Override
-    protected TaskExecutor<SwitchTask> buildInstance() {
+    protected SwitchExecutor buildInstance() {
       return new SwitchExecutor(this);
     }
+
+    @Override
+    protected void buildTransition(SwitchExecutor ex) {}
   }
 
   @Override

@@ -77,7 +77,7 @@ protected TryExecutorBuilder(
     }
 
     @Override
-    public TaskExecutor<TryTask> buildInstance() {
+    public TryExecutor buildInstance() {
       return new TryExecutor(this);
     }
   }

@@ -60,7 +60,7 @@ private Duration toLong(DurationInline durationInline) {
     }
 
     @Override
-    public TaskExecutor<WaitTask> buildInstance() {
+    public WaitExecutor buildInstance() {
       return new WaitExecutor(this);
     }
   }

@@ -73,6 +73,10 @@ private static Stream<Arguments> provideParameters() {
             "for-sum.yaml",
             Map.of("input", Arrays.asList(1, 2, 3)),
             o -> assertThat(o).isEqualTo(6)),
+        args(
+            "switch-then-loop.yaml",
+            Map.of("count", 1),
+            o -> assertThat(o).isEqualTo(Map.of("count", 6))),
         args(
             "for-collect.yaml",
             Map.of("input", Arrays.asList(1, 2, 3)),

@@ -0,0 +1,18 @@
+document:
+  dsl: 1.0.0-alpha5
+  namespace: test
+  name:  switch-loop
+  version: 0.1.0
+do:
+  - inc:
+     set:
+        count: ${.count+1}
+     then: looping
+  - looping:
+       switch:
+         - loopCount:
+             when: .count < 6
+             then: inc
+         - default:
+             then: exit
+