client config load balancer and load balancer class name are mutually…

… exclusive

load balancer client config xml and yaml examples updated

(cherry picked from commit dac66e2)

hazelcast/src/main/java/com/hazelcast/client/config/ClientConfig.java

@@ -53,6 +53,7 @@
 import static com.hazelcast.internal.config.DeclarativeConfigUtil.SYSPROP_CLIENT_CONFIG;
 import static com.hazelcast.internal.config.DeclarativeConfigUtil.validateSuffixInSystemProperty;
 import static com.hazelcast.internal.util.Preconditions.checkFalse;
+import static com.hazelcast.internal.util.Preconditions.checkHasText;
 import static com.hazelcast.internal.util.Preconditions.isNotNull;
 import static com.hazelcast.partition.strategy.StringPartitioningStrategy.getBaseName;
 
@@ -605,14 +606,17 @@ public LoadBalancer getLoadBalancer() {
     }
 
     /**
-     * Sets the {@link LoadBalancer}
+     * Sets the {@link LoadBalancer}.
+     * <p>
+     * If a load balancer class name was set, it will be removed.
      *
      * @param loadBalancer {@link LoadBalancer}
      * @return configured {@link com.hazelcast.client.config.ClientConfig} for chaining
      * @see com.hazelcast.client.LoadBalancer
      */
     public ClientConfig setLoadBalancer(LoadBalancer loadBalancer) {
         this.loadBalancer = loadBalancer;
+        this.loadBalancerClassName = null;
         return this;
     }
 
@@ -627,14 +631,17 @@ public String getLoadBalancerClassName() {
     }
 
     /**
-     * Sets load balancer class name
+     * Sets load balancer class name.
+     * <p>
+     * If a load balancer implementation was set, it will be removed.
      *
      * @param loadBalancerClassName {@link LoadBalancer}
      * @return configured {@link com.hazelcast.client.config.ClientConfig} for chaining
      * @see com.hazelcast.client.LoadBalancer
      */
-    public ClientConfig setLoadBalancerClassName(String loadBalancerClassName) {
-        this.loadBalancerClassName = loadBalancerClassName;
+    public ClientConfig setLoadBalancerClassName(@Nonnull String loadBalancerClassName) {
+        this.loadBalancerClassName = checkHasText(loadBalancerClassName, "Load balancer class name must contain text");
+        this.loadBalancer = null;
         return this;
     }
 

hazelcast/src/main/resources/hazelcast-client-full-example.xml

@@ -557,6 +557,8 @@
         It has the attribute "type". The valid values for the type of the load balancer are"
         * "random": The member the operations to be sent to is chosen randomly.
         * "round-robin": The member the operations to be sent to is chosen in a round-robin fashion.
+        * "custom": The member the operations to be sent to is chosen by provided load balancer implementation.
+                    The implementation class name is specified as text content.
     -->
     <load-balancer type="random"/>
 

hazelcast/src/main/resources/hazelcast-client-full-example.yaml

@@ -510,6 +510,8 @@ hazelcast-client:
   # It has a scalar sub-node called "type". The valid values for the type of the load balancer are:
   # * "random": The member the operations to be sent to is chosen randomly.
   # * "round-robin": The member the operations to be sent to is chosen in a round-robin fashion.
+  # * "custom": The member the operations to be sent to is chosen by provided load balancer implementation.
+  #             The implementation class name is specified in additional "class-name" key.
   #
   load-balancer:
     type: random

hazelcast/src/test/java/com/hazelcast/client/config/ClientConfigLoadBalancerTest.java

@@ -73,23 +73,6 @@ public void shouldUseConfigClassLoaderInstanceWhenClassNameNotSpecified() {
         assertSame(loadBalancer, actual);
     }
 
-    @Test
-    public void shouldUseConfigClassLoaderInstanceWhenClassNameSpecified() {
-        hazelcastFactory.newHazelcastInstance();
-
-        LoadBalancer loadBalancer = new RandomLB();
-
-        ClientConfig config = new ClientConfig();
-        config.setLoadBalancer(loadBalancer);
-        config.setLoadBalancerClassName("com.hazelcast.client.test.CustomLoadBalancer");
-
-        HazelcastInstance instance = hazelcastFactory.newHazelcastClient(config);
-        HazelcastClientInstanceImpl client = ClientTestUtil.getHazelcastClientInstanceImpl(instance);
-
-        LoadBalancer actual = client.getLoadBalancer();
-        assertSame(loadBalancer, actual);
-    }
-
     @Test
     public void shouldCreateCustomLoadBalancerWhenConfigInstanceNotProvidedAndClassNameSpecified() {
         hazelcastFactory.newHazelcastInstance();

hazelcast/src/test/java/com/hazelcast/client/config/ClientConfigTest.java

@@ -16,9 +16,11 @@
 
 package com.hazelcast.client.config;
 
+import com.hazelcast.client.LoadBalancer;
 import com.hazelcast.client.test.Employee;
 import com.hazelcast.client.test.PortableFactory;
 import com.hazelcast.client.test.TestHazelcastFactory;
+import com.hazelcast.client.util.RandomLB;
 import com.hazelcast.config.Config;
 import com.hazelcast.config.SerializationConfig;
 import com.hazelcast.core.HazelcastInstance;
@@ -38,6 +40,8 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 
 @RunWith(HazelcastParallelClassRunner.class)
 @Category({QuickTest.class, ParallelJVMTest.class})
@@ -135,4 +139,28 @@ public void testReliableTopic() {
 
         assertEquals(100, newConfig.getReadBatchSize());
     }
+
+    @Test
+    public void testSettingLoaderBalancerShouldClearLoadBalancerClassName() {
+        LoadBalancer loadBalancer = new RandomLB();
+
+        ClientConfig clientConfig = new ClientConfig();
+        clientConfig.setLoadBalancerClassName("com.hazelcast.client.test.CustomLoadBalancer");
+        clientConfig.setLoadBalancer(loadBalancer);
+
+        assertNull(clientConfig.getLoadBalancerClassName());
+        assertSame(loadBalancer, clientConfig.getLoadBalancer());
+    }
+
+    @Test
+    public void testSettingLoadBalancerClassNameShouldClearLoadBalancer() {
+        LoadBalancer loadBalancer = new RandomLB();
+
+        ClientConfig clientConfig = new ClientConfig();
+        clientConfig.setLoadBalancer(loadBalancer);
+        clientConfig.setLoadBalancerClassName("com.hazelcast.client.test.CustomLoadBalancer");
+
+        assertEquals("com.hazelcast.client.test.CustomLoadBalancer", clientConfig.getLoadBalancerClassName());
+        assertNull(clientConfig.getLoadBalancer());
+    }
 }