update signal to mutate the state, also get rid of infinite loop in workflow method

Author: chopincode

src/main/java/com/uber/cadence/samples/spring/workflows/impl/SignalWorkflowImpl.java

@@ -8,25 +8,28 @@
 public class SignalWorkflowImpl implements SignalWorkflow {
   private final Logger logger = Workflow.getLogger(SignalWorkflowImpl.class);
   private String name;
+  private String greetingMsg;
   private boolean cancel = false;
 
   @Override
   public void getGreeting(SampleMessage sampleMessage) {
     logger.info("executing SignalWorkflow::getGreeting");
     this.name = sampleMessage.GetMessage();
-    while (true) {
-      Workflow.await(() -> cancel);
-      if (cancel) {
-        logger.info("SignalWorkflow cancelled");
-        return;
-      }
-    }
+    Workflow.await(
+        () -> {
+          if (cancel) {
+            logger.info("SignalWorkflow cancelled");
+          }
+          logger.info("greeting: " + this.greetingMsg);
+          return cancel;
+        });
+    logger.info("greeting:" + this.greetingMsg);
   }
 
   @Override
   public void waitForGreeting(String greeting) {
     logger.info("received signal from SignalWorkflow:waitForName");
-    logger.info(greeting + " " + name + "!");
+    this.greetingMsg = String.format("%s, %s!", greeting, this.name);
   }
 
   @Override