conditional support jms via spring.jms.servicebus.enabled config (#50)

…enabled` config

## Purpose

Add conditional support jms via `spring.jms.servicebus.enabled` config,
in order to meet the one-click solution and step by step scenario.

## Does this introduce a breaking change?
<!-- Mark one with an "x". -->
```
[ ] Yes
[ ] No
```

## Pull Request Type
What kind of change does this Pull Request introduce?

<!-- Please check the one that applies to this PR using "x". -->
```
[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:
```

## How to Test
*  Get the code

```
git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install
```

* Test the code
<!-- Add steps to run the tests suite and/or manually test -->
```
```

## What to Check
Verify that the following are valid
* ...

## Other Information
<!-- Add any other helpful information that may be needed here. -->

Co-authored-by: Hao Zhang <[email protected]>

config/application.yml

@@ -11,6 +11,7 @@ spring:
       visits-requests: visits-requests
       visits-confirmations: visits-confirmations
     servicebus:
+      enabled: false  # disable messaging support by default
       namespace: ${SERVICEBUS_NAMESPACE}
       pricing-tier: premium
       passwordless-enabled: true

docs/09_lab_messaging/0901.md

@@ -22,6 +22,7 @@ The connection to the Service Bus needs to be stored in the `spring.jms.serviceb
          visits-requests: visits-requests
          visits-confirmations: visits-confirmations
        servicebus:
+         enabled: true
          namespace: ${SERVICEBUS_NAMESPACE}
          pricing-tier: premium
          passwordless-enabled: true
@@ -84,7 +85,7 @@ The connection to the Service Bus needs to be stored in the `spring.jms.serviceb
 
 1. In the config repository you will need to add the service bus connection information. Replace the contents of the current `application.yml` file with the contents of the [0901_application.yml file](0901_application.yml). The service bus namespace and identity client id will be injected via environment variables. This file includes the following change:
 
-   - An additional `spring.jms` section from lines `16` to `26`.
+   - An additional `spring.jms` section after the `spring.sql` section.
 
 1. Commit and push your changes to the remote repository.
 

docs/09_lab_messaging/0901_application.yml

@@ -18,6 +18,7 @@ spring:
       visits-requests: visits-requests
       visits-confirmations: visits-confirmations
     servicebus:
+      enabled: true
       namespace: ${SERVICEBUS_NAMESPACE}
       pricing-tier: premium
       passwordless-enabled: true

src/spring-petclinic-visits-service/src/main/java/org/springframework/samples/petclinic/visits/service/VisitsReceiver.java

@@ -3,6 +3,7 @@
 import java.util.Date;
 
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.jms.annotation.JmsListener;
 import org.springframework.jms.core.JmsTemplate;
 import org.springframework.samples.petclinic.visits.entities.VisitRequest;
@@ -14,6 +15,7 @@
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
+@ConditionalOnProperty(name = "spring.jms.servicebus.enabled", havingValue = "true")
 @Component
 @Slf4j
 @RequiredArgsConstructor