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Creating Spring context
| Code Block | ||
|---|---|---|
| ||
public class InitAPIImpl implements InitAPI {
@Override
public void init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> handler) {
vertx.executeBlocking(
future -> {
SpringContextUtil.init(vertx, context, ApplicationConfig.class);
future.complete();
},
result -> {
if (result.succeeded()) {
handler.handle(Future.succeededFuture(true));
} else {
handler.handle(Future.failedFuture(result.cause()));
}
});
}
} |
We implemented class SpringContextUtil to use Spring dependency injection in Vert.x applications.
SpringContextUtil#init method initializes Spring context and adds it to Vertx Context object.
Accessing Spring context from endpoint classes
| Code Block | ||
|---|---|---|
| ||
public class EholdingsProxyTypesImpl implements EholdingsProxyTypes {
private final Logger logger = LoggerFactory.getLogger(EholdingsProxyTypesImpl.class);
@Autowired
private RMAPIConfigurationService configurationService;
@Autowired
private ProxyConverter converter;
@Autowired
private HeaderValidator headerValidator;
@SuppressWarnings("squid:S1172")
public EholdingsProxyTypesImpl(Vertx vertx, String tenantId) {
SpringContextUtil.autowireDependencies(this, vertxVertx.getOrCreateContextcurrentContext());
} |
SpringContextUtil#autowireDependencies method gets Spring context from Vertx context and uses it to inject beans into EholdingsProxyTypesImpl.
RestVerticle will call constructor with parameters (Vertx vertx, String tenantId) default constructor through reflection.
@SuppressWarnings("squid:S1172") annotation is needed because Sonar can't see reflection calls and considers tenantId parameter to be unnecessary.
Declaring Spring configuration
SpringContextUtil#init uses Spring configuration class.
...
vertx and expirationTime parameters will be automatically injected by Spring, expirationTime will be set to the value of "configuration.cache.expire" property from application.properties file.
Benefits of using Spring DI
1) Spring allows to inject properties by using @Value annotation, without this we need to manually read file and share it across application.
...
| Expand |
|---|
private RMAPIConfigurationService configurationService; |
With Spring:
| Expand |
|---|
@Autowired } |
4) It resolves circular dependencies between objects.
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6) Objects are created once instead of being created on each request.
Drawbacks of using Spring DI
1) It introduces another framework that developers need to know.
2) Creating objects at the point when they are used can be easier. With DI it can be more difficult to know when object is constructed and how it is injected.Presentation on dependency injection Spring_DI.pptx