SGF-458 - Enable resolution of GemFire's DistributedSystem and System properties to be overridden in PoolFactoryBean.

(cherry picked from commit 10fadc0d9a)
Signed-off-by: John Blum <jblum@pivotal.io>

src/main/java/org/springframework/data/gemfire/client/PoolFactoryBean.java

@@ -189,15 +189,30 @@ public class PoolFactoryBean implements FactoryBean<Pool>, InitializingBean, Dis
 		return PoolManager.createFactory();
 	}
 
-	/* (non-Javadoc) */
-	void resolveDistributedSystem() {
-		if (DistributedSystemUtils.getDistributedSystem() == null) {
+	/**
+	 * Attempts to find an existing, running GemFire {@link DistributedSystem} or proceeds to create
+	 * a new {@link DistributedSystem} if one does not exist.
+	 *
+	 * @see DistributedSystemUtils#getDistributedSystem()
+	 * @see #resolveGemfireProperties()
+	 * @see #doDistributedSystemConnect(Properties)
+	 */
+	protected void resolveDistributedSystem() {
+		if (DistributedSystemUtils.isNotConnected(DistributedSystemUtils.getDistributedSystem())) {
 			doDistributedSystemConnect(resolveGemfireProperties());
 		}
 	}
 
-	/* (non-Javadoc) */
-	Properties resolveGemfireProperties() {
+	/**
+	 * Attempts to resolve existing GemFire System properties from the {@link ClientCacheFactoryBean}
+	 * if set by the user.
+	 *
+	 * @return a {@link Properties} object containing GemFire System properties
+	 * or null if no properties were configured.
+	 * @see ClientCacheFactoryBean#resolveProperties()
+	 * @see java.util.Properties
+	 */
+	protected Properties resolveGemfireProperties() {
 		try {
 			ClientCacheFactoryBean clientCacheFactoryBean = beanFactory.getBean(ClientCacheFactoryBean.class);
 			return clientCacheFactoryBean.getProperties();

src/main/java/org/springframework/data/gemfire/util/DistributedSystemUtils.java

@@ -42,4 +42,9 @@ public abstract class DistributedSystemUtils {
 		return (distributedSystem != null && distributedSystem.isConnected());
 	}
 
+	/* (non-Javadoc) */
+	public static boolean isNotConnected(DistributedSystem distributedSystem) {
+		return !isConnected(distributedSystem);
+	}
+
 }

src/test/java/org/springframework/data/gemfire/client/PoolUsingLocatorsAndServersPropertyPlaceholdersTest.java

@@ -155,7 +155,7 @@ public class PoolUsingLocatorsAndServersPropertyPlaceholdersTest {
 		}
 
 		@Override
-		void resolveDistributedSystem() {
+		protected void resolveDistributedSystem() {
 		}
 	}