Add changes after code review.

Modify

# Conflicts:
#	spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/composite/CompositeDiscoveryClient.java
#	spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/simple/SimpleDiscoveryProperties.java

docs/src/main/asciidoc/spring-cloud-commons.adoc

@@ -257,9 +257,9 @@ Otherwise, it can bubble up as the `description` of the rolled up `HealthIndicat
 ==== Ordering `DiscoveryClient` instances
 `DiscoveryClient` interface extends `Ordered` to let you define the order of the returned discovery clients, similar to
 how you can order the beans loaded by a Spring application. By default, the order of any `DiscoveryClient` is set to
-`Ordered.LOWEST_PRECEDENCE`, which equals `Integer.MAX_VALUE`. If you want to set a different order for your custom
-`DiscoveryClient` implementations, you just need to override the `getOrder()` method so that it returns the value that
-is suitable for your setup. Apart from this, you can use properties to set the order of the `DiscoveryClient`
+`0`. If you want to set a different order for your custom `DiscoveryClient` implementations, you just need to override
+the `getOrder()` method so that it returns the value that is suitable for your setup. Apart from this, you can use
+properties to set the order of the `DiscoveryClient`
 implementations provided by Spring Cloud, among others  `ConsulDiscoveryClient`, `EurekaDiscoveryClient` and
 `ZookeeperDiscoveryClient`. In order to do it, you just need to set the
 `spring.cloud.discovery.client.{clientIdentifier}.order` property to the desired value.

spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/DiscoveryClient.java

@@ -24,19 +24,24 @@ import org.springframework.core.Ordered;
 /**
  * Represents read operations commonly available to discovery services such as Netflix
  * Eureka or consul.io.
+ *
  * @author Spencer Gibb
  * @author Olga Maciaszek-Sharma
  */
 public interface DiscoveryClient extends Ordered {
 
+	int DEFAULT_ORDER = 0;
+
 	/**
 	 * A human-readable description of the implementation, used in HealthIndicator.
+	 *
 	 * @return The description.
 	 */
 	String description();
 
 	/**
 	 * Gets all ServiceInstances associated with a particular serviceId.
+	 *
 	 * @param serviceId The serviceId to query.
 	 * @return A List of ServiceInstance.
 	 */
@@ -47,8 +52,13 @@ public interface DiscoveryClient extends Ordered {
 	 */
 	List<String> getServices();
 
+	/**
+	 * Default implementation for getting order of discovery clients.
+	 *
+	 * @return order
+	 */
 	@Override
 	default int getOrder() {
-		return Ordered.LOWEST_PRECEDENCE;
+		return DEFAULT_ORDER;
 	}
 }

spring-cloud-commons/src/test/java/org/springframework/cloud/client/discovery/composite/CompositeDiscoveryClientOrderTest.java

@@ -1,9 +1,10 @@
 package org.springframework.cloud.client.discovery.composite;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.A_CUSTOM_DISCOVERY_CLIENT;
+import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.CUSTOM_DISCOVERY_CLIENT;
 import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.CUSTOM_SERVICE_ID;
-import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.THIRD_DISCOVERY_CLIENT;
+import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.DEFAULT_ORDER_DISCOVERY_CLIENT;
+import static org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientTestsConfig.FOURTH_DISCOVERY_CLIENT;
 
 import java.util.List;
 
@@ -37,11 +38,13 @@ public class CompositeDiscoveryClientOrderTest {
 
 		// then:
 		assertThat(discoveryClients.get(0).description())
-				.isEqualTo(A_CUSTOM_DISCOVERY_CLIENT);
+				.isEqualTo(CUSTOM_DISCOVERY_CLIENT);
 		assertThat(discoveryClients.get(1).description())
-				.isEqualTo("Simple Discovery Client");
+				.isEqualTo(DEFAULT_ORDER_DISCOVERY_CLIENT);
 		assertThat(discoveryClients.get(2).description())
-				.isEqualTo(THIRD_DISCOVERY_CLIENT);
+				.isEqualTo("Simple Discovery Client");
+		assertThat(discoveryClients.get(3).description())
+				.isEqualTo(FOURTH_DISCOVERY_CLIENT);
 	}
 
 	@Test

spring-cloud-commons/src/test/java/org/springframework/cloud/client/discovery/composite/CompositeDiscoveryClientTestsConfig.java

@@ -21,21 +21,27 @@ import org.springframework.context.annotation.Configuration;
 @EnableAutoConfiguration
 public class CompositeDiscoveryClientTestsConfig {
 
-	static final String A_CUSTOM_DISCOVERY_CLIENT = "A custom discovery client";
-	static final String THIRD_DISCOVERY_CLIENT = "Third discovery client";
+	static final String DEFAULT_ORDER_DISCOVERY_CLIENT = "Default order discovery client";
+	static final String CUSTOM_DISCOVERY_CLIENT = "A custom discovery client";
+	static final String FOURTH_DISCOVERY_CLIENT = "Fourth discovery client";
 	static final String CUSTOM_SERVICE_ID = "custom";
 
 	@Bean
 	public DiscoveryClient customDiscoveryClient() {
-		return aDiscoveryClient(1, A_CUSTOM_DISCOVERY_CLIENT);
+		return aDiscoveryClient(-1, CUSTOM_DISCOVERY_CLIENT);
 	}
 
 	@Bean
 	public DiscoveryClient thirdOrderCustomDiscoveryClient() {
-		return aDiscoveryClient(3, THIRD_DISCOVERY_CLIENT);
+		return aDiscoveryClient(3, FOURTH_DISCOVERY_CLIENT);
 	}
 
-	private DiscoveryClient aDiscoveryClient(int order, String description) {
+	@Bean
+	public DiscoveryClient defaultOrderDiscoveryClient() {
+		return aDiscoveryClient(null, DEFAULT_ORDER_DISCOVERY_CLIENT);
+	}
+
+	private DiscoveryClient aDiscoveryClient(Integer order, String description) {
 		return new DiscoveryClient() {
 			@Override
 			public String description() {
@@ -59,7 +65,7 @@ public class CompositeDiscoveryClientTestsConfig {
 
 			@Override
 			public int getOrder() {
-				return order;
+				return order != null ? order : DiscoveryClient.super.getOrder();
 			}
 		};
 	}