Use Temporal update to increase counter

src/main/java/io/iworkflow/controller/CounterWorkflowController.java

@@ -0,0 +1,37 @@
+package io.iworkflow.controller;
+
+import io.iworkflow.core.Client;
+import io.iworkflow.workflow.update.CounterWorkflow;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@Controller
+@RequestMapping("/counter")
+public class CounterWorkflowController {
+
+    private final Client client;
+
+    public CounterWorkflowController(
+            final Client client
+    ) {
+        this.client = client;
+    }
+
+    @GetMapping("/start")
+    public ResponseEntity<String> start(
+            @RequestParam String id
+    ) {
+        client.startWorkflow(CounterWorkflow.class, id, 3600);
+        return ResponseEntity.ok("success");
+    }
+
+    @GetMapping("/inc")
+    ResponseEntity<Integer> verify(
+            @RequestParam String id) {
+        final CounterWorkflow rpcStub = client.newRpcStub(CounterWorkflow.class, id);
+        return ResponseEntity.ok(client.invokeRPC(rpcStub::inc));
+    }
+}

src/main/java/io/iworkflow/workflow/update/CounterWorkflow.java

@@ -0,0 +1,50 @@
+package io.iworkflow.workflow.update;
+
+import io.iworkflow.core.Context;
+import io.iworkflow.core.ObjectWorkflow;
+import io.iworkflow.core.RPC;
+import io.iworkflow.core.StateDef;
+import io.iworkflow.core.communication.Communication;
+import io.iworkflow.core.persistence.DataAttributeDef;
+import io.iworkflow.core.persistence.Persistence;
+import io.iworkflow.core.persistence.PersistenceFieldDef;
+import io.iworkflow.gen.models.PersistenceLoadingType;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+@Component
+
+public class CounterWorkflow implements ObjectWorkflow {
+
+    public static final String DA_COUNT = "COUNT";
+
+    @Override
+    public List<StateDef> getWorkflowStates() {
+        return new ArrayList<>();
+    }
+
+    @Override
+    public List<PersistenceFieldDef> getPersistenceSchema() {
+        return Arrays.asList(
+                DataAttributeDef.create(Integer.class, DA_COUNT)
+        );
+    }
+
+    // Atomically read/write data attributes in RPC will use Temporal sync update features
+    @RPC(
+            dataAttributesLoadingType = PersistenceLoadingType.PARTIAL_WITH_EXCLUSIVE_LOCK,
+            dataAttributesLockingKeys = {DA_COUNT}
+    )
+    public int inc(Context context, Persistence persistence, Communication communication) {
+        Integer count = persistence.getDataAttribute(DA_COUNT, Integer.class);
+        if (count == null) {
+            count = 0;
+        }
+        count++;
+        persistence.setDataAttribute(DA_COUNT, count);
+        return count;
+    }
+}