Updates for nullabilty in ServiceInstance

See spring-cloud/spring-cloud-commons#1604

Author: spencergibb

spring-cloud-gateway-server-webflux/src/main/java/org/springframework/cloud/gateway/discovery/DiscoveryClientRouteDefinitionLocator.java

@@ -102,7 +102,7 @@ public Flux<RouteDefinition> getRouteDefinitions() {
 		return serviceInstances.filter(instances -> !instances.isEmpty())
 			.flatMap(Flux::fromIterable)
 			.filter(includePredicate)
-			.collectMap(instance -> Objects.requireNonNull(instance.getServiceId()))
+			.collectMap(instance -> instance.getServiceId())
 			// remove duplicates
 			.flatMapMany(map -> Flux.fromIterable(map.values()))
 			.map(instance -> {
@@ -181,15 +181,15 @@ private DelegatingServiceInstance(ServiceInstance delegate, DiscoveryLocatorProp
 		}
 
 		@Override
-		public @Nullable String getServiceId() {
-			if (properties.isLowerCaseServiceId() && delegate.getServiceId() != null) {
+		public String getServiceId() {
+			if (properties.isLowerCaseServiceId()) {
 				return delegate.getServiceId().toLowerCase(Locale.ROOT);
 			}
 			return delegate.getServiceId();
 		}
 
 		@Override
-		public @Nullable String getHost() {
+		public String getHost() {
 			return delegate.getHost();
 		}
 

spring-cloud-gateway-server-webflux/src/main/java/org/springframework/cloud/gateway/filter/LoadBalancerServiceInstanceCookieFilter.java

@@ -62,12 +62,10 @@ public LoadBalancerServiceInstanceCookieFilter(
 	@Override
 	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
 		Response<ServiceInstance> serviceInstanceResponse = exchange.getAttribute(GATEWAY_LOADBALANCER_RESPONSE_ATTR);
-		if (serviceInstanceResponse == null || serviceInstanceResponse.getServer() == null) {
-			return chain.filter(exchange);
-		}
-		if (!serviceInstanceResponse.hasServer()) {
+		if (serviceInstanceResponse == null || !serviceInstanceResponse.hasServer()) {
 			return chain.filter(exchange);
 		}
+		@SuppressWarnings("NullAway") // protected by hasServer() above
 		LoadBalancerProperties properties = loadBalancerClientFactory != null
 				? loadBalancerClientFactory.getProperties(serviceInstanceResponse.getServer().getServiceId())
 				: loadBalancerProperties;

spring-cloud-gateway-server-webmvc/src/main/java/org/springframework/cloud/gateway/server/mvc/filter/LoadBalancerFilterFunctions.java

@@ -156,12 +156,12 @@ static class DelegatingServiceInstance implements ServiceInstance {
 		}
 
 		@Override
-		public @Nullable String getServiceId() {
+		public String getServiceId() {
 			return delegate.getServiceId();
 		}
 
 		@Override
-		public @Nullable String getHost() {
+		public String getHost() {
 			return delegate.getHost();
 		}