add a method to construct TypeToken from Class

Author: zhongkechen

sdk/src/main/java/com/amazonaws/lambda/durable/DurableContext.java

@@ -56,7 +56,7 @@ public class DurableContext {
     public <T> T step(String name, Class<T> resultType, Supplier<T> func) {
         return step(
                 name,
-                resultType,
+                TypeToken.get(resultType),
                 func,
                 StepConfig.builder()
                         .retryStrategy(RetryStrategies.Presets.NO_RETRY)
@@ -86,29 +86,15 @@ public <T> T step(String name, TypeToken<T> typeToken, Supplier<T> func, StepCon
     public <T> DurableFuture<T> stepAsync(String name, Class<T> resultType, Supplier<T> func) {
         return stepAsync(
                 name,
-                resultType,
+                TypeToken.get(resultType),
                 func,
                 StepConfig.builder()
                         .retryStrategy(RetryStrategies.Presets.NO_RETRY)
                         .build());
     }
 
     public <T> DurableFuture<T> stepAsync(String name, Class<T> resultType, Supplier<T> func, StepConfig config) {
-        var operationId = nextOperationId();
-
-        // Validate replay consistency
-        var existing = executionManager.getOperation(operationId);
-        if (existing != null) {
-            validateReplay(operationId, OperationType.STEP, name, existing);
-        }
-
-        // Create and start step operation
-        StepOperation<T> operation =
-                new StepOperation<>(operationId, name, func, resultType, config, executionManager, logger, serDes);
-
-        operation.execute(); // Start the step (returns immediately)
-
-        return new DurableFuture<>(operation);
+        return stepAsync(name, TypeToken.get(resultType), func, config);
     }
 
     public <T> DurableFuture<T> stepAsync(String name, TypeToken<T> typeToken, Supplier<T> func) {

sdk/src/main/java/com/amazonaws/lambda/durable/DurableExecutor.java

@@ -156,7 +156,7 @@ private static <I> I extractUserInput(Operation executionOp, SerDes serDes, Clas
         }
 
         var inputPayload = executionOp.executionDetails().inputPayload();
-        return serDes.deserialize(inputPayload, inputType);
+        return serDes.deserialize(inputPayload, TypeToken.get(inputType));
     }
 
     public static <I, O> RequestHandler<DurableExecutionInput, DurableExecutionOutput> wrap(

sdk/src/main/java/com/amazonaws/lambda/durable/TypeToken.java

@@ -44,6 +44,14 @@ protected TypeToken() {
         }
     }
 
+    private TypeToken(Type type) {
+        this.type = type;
+    }
+
+    public static <U> TypeToken<U> get(Class<U> clazz) {
+        return new TypeToken<>(clazz) {};
+    }
+
     /**
      * Returns the captured type.
      *

sdk/src/main/java/com/amazonaws/lambda/durable/operation/StepOperation.java

@@ -341,7 +341,7 @@ public T get() {
             if (resultTypeToken != null) {
                 return serDes.deserialize(result, resultTypeToken);
             } else {
-                return serDes.deserialize(result, resultType);
+                return serDes.deserialize(result, TypeToken.get(resultType));
             }
         } else {
             // It failed so there's some kind of throwable. If we're using a serDes with

sdk/src/main/java/com/amazonaws/lambda/durable/serde/JacksonSerDes.java

@@ -54,16 +54,6 @@ public String serialize(Object value) {
         }
     }
 
-    @Override
-    public <T> T deserialize(String data, Class<T> type) {
-        if (data == null) return null;
-        try {
-            return mapper.readValue(data, type);
-        } catch (Exception e) {
-            throw new SerDesException("Deserialization failed for type: " + type.getName(), e);
-        }
-    }
-
     @Override
     public <T> T deserialize(String data, TypeToken<T> typeToken) {
         if (data == null) return null;

sdk/src/main/java/com/amazonaws/lambda/durable/serde/SerDes.java

@@ -18,16 +18,6 @@ public interface SerDes {
      */
     String serialize(Object value);
 
-    /**
-     * Deserializes a JSON string to an object of the specified type.
-     *
-     * @param data the JSON string to deserialize
-     * @param type the class of the target type
-     * @param <T> the target type
-     * @return the deserialized object, or null if data is null
-     */
-    <T> T deserialize(String data, Class<T> type);
-
     /**
      * Deserializes a JSON string to an object of the specified generic type.
      *

sdk/src/test/java/com/amazonaws/lambda/durable/DurableExecutionWrapperTest.java

@@ -4,8 +4,6 @@
 
 import static java.util.List.of;
 import static org.junit.jupiter.api.Assertions.*;
-import static org.mockito.ArgumentMatchers.*;
-import static org.mockito.Mockito.*;
 
 import com.amazonaws.lambda.durable.client.DurableExecutionClient;
 import com.amazonaws.lambda.durable.model.DurableExecutionInput;
@@ -78,7 +76,7 @@ void testWrapperPattern() {
         assertEquals(ExecutionStatus.SUCCEEDED, output.status());
         assertNotNull(output.result());
 
-        var result = serDes.deserialize(output.result(), TestOutput.class);
+        var result = serDes.deserialize(output.result(), TypeToken.get(TestOutput.class));
         assertEquals("Wrapped: test", result.result);
     }
 
@@ -108,7 +106,7 @@ void testWrapperWithMethodReference() {
         var output = handler.handleRequest(input, null);
 
         assertEquals(ExecutionStatus.SUCCEEDED, output.status());
-        var result = serDes.deserialize(output.result(), TestOutput.class);
+        var result = serDes.deserialize(output.result(), TypeToken.get(TestOutput.class));
         assertEquals("Method: method-ref", result.result);
     }
 

sdk/src/test/java/com/amazonaws/lambda/durable/serde/JacksonSerDesTest.java

@@ -8,6 +8,7 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.amazonaws.lambda.durable.TypeToken;
 import com.amazonaws.lambda.durable.exception.SerDesException;
 import org.junit.jupiter.api.Test;
 
@@ -21,7 +22,7 @@ void testRoundTrip() {
         var original = new TestData("test", 42);
 
         var json = serDes.serialize(original);
-        var deserialized = serDes.deserialize(json, TestData.class);
+        var deserialized = serDes.deserialize(json, TypeToken.get(TestData.class));
 
         assertEquals(original, deserialized);
     }
@@ -31,7 +32,7 @@ void testNullHandling() {
         var serDes = new JacksonSerDes();
 
         assertNull(serDes.serialize(null));
-        assertNull(serDes.deserialize(null, String.class));
+        assertNull(serDes.deserialize(null, TypeToken.get(String.class)));
     }
 
     @Test
@@ -40,7 +41,7 @@ void testDeserializationThrowsSerDesException() {
         var invalidJson = "{invalid json}";
 
         var exception = assertThrows(SerDesException.class, () -> {
-            serDes.deserialize(invalidJson, TestData.class);
+            serDes.deserialize(invalidJson, TypeToken.get(TestData.class));
         });
 
         assertTrue(exception.getMessage().contains("Deserialization failed"));
@@ -79,7 +80,7 @@ void testSerDesExceptionExtendsRuntimeException() {
 
         // Verify SerDesException is a RuntimeException (unchecked)
         assertThrows(RuntimeException.class, () -> {
-            serDes.deserialize(invalidJson, TestData.class);
+            serDes.deserialize(invalidJson, TypeToken.get(TestData.class));
         });
     }
 }

sdk/src/test/java/com/amazonaws/lambda/durable/serde/JacksonSerDesTypeTokenTest.java

@@ -21,7 +21,7 @@ void setUp() {
     }
 
     @Test
-    void testDeserializeListOfStrings() {
+    void testDeserializeListGetStrings() {
         var json = "[\"apple\",\"banana\",\"cherry\"]";
         var token = new TypeToken<List<String>>() {};
 
@@ -35,7 +35,7 @@ void testDeserializeListOfStrings() {
     }
 
     @Test
-    void testDeserializeMapOfStringToInteger() {
+    void testDeserializeMapGetStringToInteger() {
         var json = "{\"one\":1,\"two\":2,\"three\":3}";
         var token = new TypeToken<Map<String, Integer>>() {};
 
@@ -62,7 +62,7 @@ void testDeserializeNestedGeneric() {
     }
 
     @Test
-    void testDeserializeListOfMaps() {
+    void testDeserializeListGetMaps() {
         var json = "[{\"name\":\"Alice\",\"age\":30},{\"name\":\"Bob\",\"age\":25}]";
         var token = new TypeToken<List<Map<String, Object>>>() {};
 
@@ -175,7 +175,7 @@ public TestObject(String name, int value) {
     }
 
     @Test
-    void testDeserializeListOfCustomObjects() {
+    void testDeserializeListGetCustomObjects() {
         var json = "[{\"name\":\"test1\",\"value\":10},{\"name\":\"test2\",\"value\":20}]";
         var token = new TypeToken<List<TestObject>>() {};