Converted @DonNotCompleteOnReturn to Activity.doNotCompleteOnReturn() (#112)

* Switched DonCompleteOnReturn to a method call from annotation

* Converted Windows end of line to unix

Author: mfateev

README.md

@@ -241,7 +241,7 @@ A workflow must define an interface class. All its methods must have one of the
 parameters (like executionStartToCloseTimeoutSeconds) that are not specified through the annotation must be provided at runtime.
 - @Signal indicates a method that reacts to external signals. Must have a `void` return type.
 - @Query indicates a method that reacts to synchronous query requests.
-It is possible to have more than method with the same annotation.
+It is possible to have more than one method with the same annotation.
 ```java
 public interface FileProcessingWorkflow {
 
@@ -267,8 +267,8 @@ WorkflowClient workflowClient = WorkflowClient.newClient(cadenceServiceHost, cad
 // Create workflow stub
 FileProcessingWorkflow workflow = workflowClient.newWorkflowStub(FileProcessingWorkflow.class);
 ```
-There are two ways to start workflow execution. Synchronously and asynchronously. Synchronous invocation starts a workflow
-and then waits for its completion. If process that started workflow crashes or stops waiting workflow continues execution.
+There are two ways to start workflow execution synchronously and asynchronously. Synchronous invocation starts a workflow
+and then waits for its completion. If process that started workflow crashes or stops the waiting workflow continues execution.
 As workflows are potentially long running and crashes of clients happen it is not very commonly found in production use.
 Asynchronous start initiates workflow execution and immediately returns to the caller. This is most common way to start 
 workflows in production code.
@@ -316,7 +316,7 @@ It takes activity type and activity options as arguments. Activity options are n
 Calling a method on this interface invokes an activity that implements this method. 
 An activity invocation synchronously blocks until the activity completes (or fails or times out). Even if activity 
 execution takes a few months the workflow code still see it as a single synchronous invocation.
-Isn't it great? I doesn't matter what happens to the processes that host the worklfow. The business logic code
+Isn't it great? I doesn't matter what happens to the processes that host the workflow. The business logic code
 just sees a single method call.
 ```java
 public class FileProcessingWorkflowImpl implements FileProcessingWorkflow {
@@ -501,8 +501,8 @@ Calling methods annotated with @QueryMethod is not allowed from within a workflo
 
 Cadence uses [event sourcing](https://docs.microsoft.com/en-us/azure/architecture/patterns/event-sourcing) to recover 
 the state of a workflow object including its threads and local variable values.
-. In essence every time a workflow state has to be restored its code is reexecuted from the beginning ignoring side 
-effects (like activity invocations) which were already recorded in the workflow event history.
+. In essence every time a workflow state has to be restored its code is reexecuted from the beginning. When replaying side 
+effects (like activity invocations) are ignored as they are already recorded in the workflow event history.
  Don't get confused, when writing workflow logic the replay is not visible,
 so the code should be written as it executes only once. But this design still puts the following constraints on the workflow 
 implementation:

src/main/java/com/uber/cadence/activity/Activity.java

@@ -31,6 +31,15 @@
  */
 public final class Activity {
 
+    /**
+     * If this method is called during an activity execution then activity is not going to complete
+     * when its method returns. It is expected to be completed asynchronously using
+     * {@link com.uber.cadence.client.ActivityCompletionClient}.
+     */
+    public static void doNotCompleteOnReturn() {
+        ActivityInternal.doNotCompleteOnReturn();
+    }
+
     /**
      * @return task token that is required to report task completion when
      * manual activity completion is used.

src/main/java/com/uber/cadence/activity/DoNotCompleteOnReturn.java

@@ -18,12 +18,12 @@
 package com.uber.cadence.client;
 
 import com.uber.cadence.WorkflowExecution;
+import com.uber.cadence.activity.Activity;
 
 import java.util.concurrent.CancellationException;
 
 /**
- * Used to complete asynchronously activities that have their implementation method annotated with
- * {@link com.uber.cadence.activity.DoNotCompleteOnReturn}.
+ * Used to complete asynchronously activities that called {@link Activity#doNotCompleteOnReturn()}.
  * <p>
  * Use {@link WorkflowClient#newActivityCompletionClient()} to create an instance.
  * </p>

src/main/java/com/uber/cadence/client/ActivityCompletionClient.java

@@ -26,15 +26,15 @@
 import com.uber.cadence.internal.replay.SignalExternalWorkflowParameters;
 
 public interface GenericWorkflowClientExternal {
-    
+
     WorkflowExecution startWorkflow(StartWorkflowExecutionParameters startParameters) throws WorkflowExecutionAlreadyStartedError;
-    
+
     void signalWorkflowExecution(SignalExternalWorkflowParameters signalParameters);
-    
+
     void requestCancelWorkflowExecution(WorkflowExecution execution);
-    
+
     byte[] queryWorkflow(QueryWorkflowParameters queryParameters);
-    
+
     void terminateWorkflowExecution(TerminateWorkflowExecutionParameters terminateParameters);
 
     String generateUniqueId();

src/main/java/com/uber/cadence/internal/external/GenericWorkflowClientExternal.java

@@ -16,16 +16,16 @@
  */
 
 package com.uber.cadence.internal.external;
-
-import java.util.concurrent.CancellationException;
-
-public abstract class ManualActivityCompletionClient {
-
-    public abstract void complete(Object result);
-    
-    public abstract void fail(Throwable failure);
-    
-    public abstract void recordHeartbeat(Object details) throws CancellationException;
-    
-    public abstract void reportCancellation(Object details);
-}
+
+import java.util.concurrent.CancellationException;
+
+public abstract class ManualActivityCompletionClient {
+
+    public abstract void complete(Object result);
+
+    public abstract void fail(Throwable failure);
+
+    public abstract void recordHeartbeat(Object details) throws CancellationException;
+
+    public abstract void reportCancellation(Object details);
+}

src/main/java/com/uber/cadence/internal/external/ManualActivityCompletionClient.java

@@ -16,13 +16,13 @@
  */
 
 package com.uber.cadence.internal.external;
-
-
-import com.uber.cadence.WorkflowExecution;
-
-public abstract class ManualActivityCompletionClientFactory {
-
-    public abstract ManualActivityCompletionClient getClient(byte[] taskToken);
-
-    public abstract ManualActivityCompletionClient getClient(WorkflowExecution execution, String activityId);
-}
+
+
+import com.uber.cadence.WorkflowExecution;
+
+public abstract class ManualActivityCompletionClientFactory {
+
+    public abstract ManualActivityCompletionClient getClient(byte[] taskToken);
+
+    public abstract ManualActivityCompletionClient getClient(WorkflowExecution execution, String activityId);
+}

src/main/java/com/uber/cadence/internal/external/ManualActivityCompletionClientFactory.java

@@ -16,55 +16,55 @@
  */
 
 package com.uber.cadence.internal.external;
-
-import com.uber.cadence.WorkflowExecution;
-import com.uber.cadence.WorkflowService;
-import com.uber.cadence.converter.DataConverter;
-
-public class ManualActivityCompletionClientFactoryImpl extends ManualActivityCompletionClientFactory {
-
-    private final WorkflowService.Iface service;
-
-    private final DataConverter dataConverter;
-    private final String domain;
-
-    public ManualActivityCompletionClientFactoryImpl(WorkflowService.Iface service, String domain, DataConverter dataConverter) {
-        this.service = service;
-        this.domain = domain;
-        this.dataConverter = dataConverter;
-    }
-
-    public WorkflowService.Iface getService() {
-        return service;
-    }
-
-    public DataConverter getDataConverter() {
-        return dataConverter;
-    }
-
-    @Override
-    public ManualActivityCompletionClient getClient(byte[] taskToken) {
-        if (service == null) {
-            throw new IllegalStateException("required property service is null");
-        }
-        if (dataConverter == null) {
-            throw new IllegalStateException("required property dataConverter is null");
-        }
-        if (taskToken == null || taskToken.length == 0) {
-            throw new IllegalArgumentException("null or empty task token");
-        }
-        return new ManualActivityCompletionClientImpl(service, taskToken, dataConverter);
-    }
-
-    @Override
-    public ManualActivityCompletionClient getClient(WorkflowExecution execution, String activityId) {
-        if (execution == null) {
-            throw new IllegalArgumentException("null execution");
-        }
-        if (activityId == null) {
-            throw new IllegalArgumentException("null activityId");
-        }
-        return new ManualActivityCompletionClientImpl(service, domain, execution, activityId, dataConverter);
-    }
-
-}
+
+import com.uber.cadence.WorkflowExecution;
+import com.uber.cadence.WorkflowService;
+import com.uber.cadence.converter.DataConverter;
+
+public class ManualActivityCompletionClientFactoryImpl extends ManualActivityCompletionClientFactory {
+
+    private final WorkflowService.Iface service;
+
+    private final DataConverter dataConverter;
+    private final String domain;
+
+    public ManualActivityCompletionClientFactoryImpl(WorkflowService.Iface service, String domain, DataConverter dataConverter) {
+        this.service = service;
+        this.domain = domain;
+        this.dataConverter = dataConverter;
+    }
+
+    public WorkflowService.Iface getService() {
+        return service;
+    }
+
+    public DataConverter getDataConverter() {
+        return dataConverter;
+    }
+
+    @Override
+    public ManualActivityCompletionClient getClient(byte[] taskToken) {
+        if (service == null) {
+            throw new IllegalStateException("required property service is null");
+        }
+        if (dataConverter == null) {
+            throw new IllegalStateException("required property dataConverter is null");
+        }
+        if (taskToken == null || taskToken.length == 0) {
+            throw new IllegalArgumentException("null or empty task token");
+        }
+        return new ManualActivityCompletionClientImpl(service, taskToken, dataConverter);
+    }
+
+    @Override
+    public ManualActivityCompletionClient getClient(WorkflowExecution execution, String activityId) {
+        if (execution == null) {
+            throw new IllegalArgumentException("null execution");
+        }
+        if (activityId == null) {
+            throw new IllegalArgumentException("null activityId");
+        }
+        return new ManualActivityCompletionClientImpl(service, domain, execution, activityId, dataConverter);
+    }
+
+}