added support for server URI strings for use with mongoDB clusters, c…

…loses #2

README.md

@@ -38,6 +38,10 @@ WAR file `para-x.y.z.war`. Para will look for plugins inside `lib` and pick up t
 
 Here are all the configuration properties for this plugin (these go inside your `application.conf`):
 ```ini
+# setting the URI will override host:port below
+# URI is left blank by default
+para.mongodb.uri = ""
+
 para.mongodb.host = "localhost"
 para.mongodb.port = 27017
 para.mongodb.database = "MyApp"
@@ -47,6 +51,11 @@ para.mongodb.ssl_enabled = false
 para.mongodb.ssl_allow_all = false
 ```
 
+You have the option to set either the server URI as a string (e.g. `mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]]`) or set the 
+host and port combination for a single server instance. The first option allows you to specify multiple server hosts.
+If the URI has a non-blank value in the configuration file, it will override the host+port settings.
+For detils about the server URI syntax, read the docs for [MongoClientURI](https://mongodb.github.io/mongo-java-driver/3.4/javadoc/com/mongodb/MongoClientURI.html).
+
 Finally, set the config property:
 ```
 para.dao = "MongoDBDAO"

src/main/java/com/erudika/para/persistence/MongoDBUtils.java

@@ -45,6 +45,7 @@ public final class MongoDBUtils {
 	private static final Logger logger = LoggerFactory.getLogger(MongoDBUtils.class);
 	private static MongoClient mongodbClient;
 	private static MongoDatabase mongodb;
+	private static final String DBURI = Config.getConfigParam("mongodb.uri", "");
 	private static final String DBHOST = Config.getConfigParam("mongodb.host", "localhost");
 	private static final int DBPORT = Config.getConfigInt("mongodb.port", 27017);
 	private static final boolean SSL = Config.getConfigBoolean("mongodb.ssl_enabled", false);
@@ -63,9 +64,14 @@ public static MongoDatabase getClient() {
 		if (mongodb != null) {
 			return mongodb;
 		}
-
-		logger.info("MongoDB host: " + DBHOST + ":" + DBPORT + ", database: " + DBNAME);
-		ServerAddress s = new ServerAddress(DBHOST, DBPORT);
+		ServerAddress s;
+		if (StringUtils.isBlank(DBURI)) {
+			logger.info("MongoDB host: " + DBHOST + ":" + DBPORT + ", database: " + DBNAME);
+			s = new ServerAddress(DBHOST, DBPORT);
+		} else {
+			logger.info("MongoDB host: " + DBURI + ", database: " + DBNAME);
+			s = new ServerAddress(DBURI);
+		}
 		MongoClientOptions options = MongoClientOptions.builder().
 				sslEnabled(SSL).sslInvalidHostNameAllowed(SSL_ALLOW_ALL).build();