Merge pull request #1977 from wind57/minor_simplifications_with_flux_defer

do not use Flux::defer when there is no need

Author: ryanjbaxter

spring-cloud-kubernetes-client-loadbalancer/src/main/java/org/springframework/cloud/kubernetes/client/loadbalancer/KubernetesClientServicesListSupplier.java

@@ -82,7 +82,7 @@ else if (!discoveryProperties.namespaces().isEmpty()) {
 		}
 
 		LOG.debug(() -> "found services : " + result);
-		return Flux.defer(() -> Flux.just(result));
+		return Flux.just(result);
 	}
 
 	private void addMappedService(KubernetesServiceInstanceMapper<V1Service> mapper, List<ServiceInstance> services,

spring-cloud-kubernetes-fabric8-discovery/src/main/java/org/springframework/cloud/kubernetes/fabric8/discovery/reactive/KubernetesReactiveDiscoveryClient.java

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.kubernetes.fabric8.discovery.reactive;
 
+import java.util.Objects;
+
 import io.fabric8.kubernetes.client.KubernetesClient;
 import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Schedulers;
@@ -25,7 +27,6 @@
 import org.springframework.cloud.kubernetes.commons.discovery.KubernetesDiscoveryProperties;
 import org.springframework.cloud.kubernetes.fabric8.discovery.KubernetesClientServicesFunction;
 import org.springframework.cloud.kubernetes.fabric8.discovery.KubernetesDiscoveryClient;
-import org.springframework.util.Assert;
 
 /**
  * Kubernetes implementation of {@link ReactiveDiscoveryClient}. Currently relies on the
@@ -50,7 +51,7 @@ public String description() {
 
 	@Override
 	public Flux<ServiceInstance> getInstances(String serviceId) {
-		Assert.notNull(serviceId, "[Assertion failed] - the object argument must not be null");
+		Objects.requireNonNull(serviceId, "serviceId must not be null");
 		return Flux.defer(() -> Flux.fromIterable(kubernetesDiscoveryClient.getInstances(serviceId)))
 			.subscribeOn(Schedulers.boundedElastic());
 	}

spring-cloud-kubernetes-fabric8-loadbalancer/src/main/java/org/springframework/cloud/kubernetes/fabric8/loadbalancer/Fabric8ServicesListSupplier.java

@@ -101,7 +101,7 @@ else if (!discoveryProperties.namespaces().isEmpty()) {
 		}
 
 		LOG.debug(() -> "found services : " + result);
-		return Flux.defer(() -> Flux.just(result));
+		return Flux.just(result);
 	}
 
 	private void addMappedService(KubernetesServiceInstanceMapper<Service> mapper, List<ServiceInstance> services,