Allowing passing WorkflowModel as function input parameter

experimental/lambda/src/main/java/io/serverlessworkflow/impl/expressions/func/JavaModel.java

@@ -94,6 +94,9 @@ public Class<?> objectClass() {
 
   @Override
   public <T> Optional<T> as(Class<T> clazz) {
+    if (WorkflowModel.class.isAssignableFrom(clazz)) {
+      return Optional.of(clazz.cast(this));
+    }
     return object != null && clazz.isAssignableFrom(object.getClass())
         ? Optional.of(clazz.cast(object))
         : Optional.empty();

experimental/lambda/src/test/java/io/serverless/workflow/impl/CallTest.java

@@ -33,6 +33,7 @@
 import io.serverlessworkflow.api.types.func.SwitchCaseFunction;
 import io.serverlessworkflow.impl.WorkflowApplication;
 import io.serverlessworkflow.impl.WorkflowDefinition;
+import io.serverlessworkflow.impl.WorkflowModel;
 import io.serverlessworkflow.impl.expressions.TaskMetadataKeys;
 import java.util.Collection;
 import java.util.List;
@@ -166,6 +167,30 @@ void testIf() throws InterruptedException, ExecutionException {
     }
   }
 
+  @Test
+  void testIfWithModel() throws InterruptedException, ExecutionException {
+    try (WorkflowApplication app = WorkflowApplication.builder().build()) {
+      Workflow workflow =
+          new Workflow()
+              .withDocument(
+                  new Document().withNamespace("test").withName("testIf").withVersion("1.0"))
+              .withDo(
+                  List.of(
+                      new TaskItem(
+                          "java",
+                          new Task()
+                              .withCallTask(
+                                  new CallTaskJava(
+                                      withPredicate(
+                                          CallJava.function(
+                                              CallTest::zeroWithModel, WorkflowModel.class),
+                                          CallTest::isOdd))))));
+      WorkflowDefinition definition = app.workflowDefinition(workflow);
+      assertThat(definition.instance(3).start().get().asNumber().orElseThrow()).isEqualTo(0);
+      assertThat(definition.instance(4).start().get().asNumber().orElseThrow()).isEqualTo(4);
+    }
+  }
+
   private <T> CallJava withPredicate(CallJava call, Predicate<T> pred) {
     return (CallJava)
         call.withMetadata(
@@ -184,6 +209,10 @@ public static int zero(Integer value) {
     return 0;
   }
 
+  public static int zeroWithModel(WorkflowModel value) {
+    return 0;
+  }
+
   public static Integer sum(Object model, Integer item) {
     return model instanceof Collection ? item : (Integer) model + item;
   }