Document tnsnames alias and update example

Author: Michael-A-McMahon

sample/src/main/java/oracle/r2dbc/samples/DescriptorURL.java

@@ -23,7 +23,7 @@
 
 import io.r2dbc.spi.ConnectionFactories;
 import io.r2dbc.spi.ConnectionFactoryOptions;
-import io.r2dbc.spi.Option;
+import oracle.r2dbc.OracleR2dbcOptions;
 import reactor.core.publisher.Mono;
 
 import static oracle.r2dbc.samples.DatabaseConfig.HOST;
@@ -47,15 +47,16 @@ public class DescriptorURL {
 
   /**
    * A TNS descriptor specifying the HOST, PORT, and SERVICE_NAME read from
-   * {@link DatabaseConfig}.
+   * {@link DatabaseConfig}. These values can be configured in a
+   * config.properties file of the current directory.
    */
   private static final String DESCRIPTOR = "(DESCRIPTION=" +
     "(ADDRESS=(HOST="+HOST+")(PORT="+PORT+")(PROTOCOL=tcp))" +
     "(CONNECT_DATA=(SERVICE_NAME="+SERVICE_NAME+")))";
 
   public static void main(String[] args) {
     // A descriptor may appear in the query section of an R2DBC URL:
-    String r2dbcUrl = "r2dbc:oracle://?oracleNetDescriptor="+DESCRIPTOR;
+    String r2dbcUrl = "r2dbc:oracle://?oracle.r2dbc.descriptor="+DESCRIPTOR;
     Mono.from(ConnectionFactories.get(ConnectionFactoryOptions.parse(r2dbcUrl)
       .mutate()
       .option(ConnectionFactoryOptions.USER, USER)
@@ -67,15 +68,15 @@ public static void main(String[] args) {
           "SELECT 'Connected with TNS descriptor' FROM sys.dual")
           .execute())
           .flatMapMany(result ->
-            result.map((row, metadata) -> row.get(0, String.class)))
+            result.map(row -> row.get(0, String.class)))
           .concatWith(Mono.from(connection.close()).cast(String.class)))
       .toStream()
       .forEach(System.out::println);
 
     // A descriptor may also be specified as an Option
     Mono.from(ConnectionFactories.get(ConnectionFactoryOptions.builder()
       .option(ConnectionFactoryOptions.DRIVER, "oracle")
-      .option(Option.valueOf("oracleNetDescriptor"), DESCRIPTOR)
+      .option(OracleR2dbcOptions.DESCRIPTOR, DESCRIPTOR)
       .option(ConnectionFactoryOptions.USER, USER)
       .option(ConnectionFactoryOptions.PASSWORD, PASSWORD)
       .build())

src/main/java/oracle/r2dbc/OracleR2dbcOptions.java

@@ -35,7 +35,9 @@ private OracleR2dbcOptions() {}
 
   /**
    * Extended {@code Option} that specifies an Oracle Net Connect Descriptor
-   * of the form "(DESCRIPTION=...)"
+   * of the form "(DESCRIPTION=...)". If {@link #TNS_ADMIN} is specified,
+   * then the value of this {@code Option} may be set to a tnsnames.ora
+   * alias.
    */
   public static final Option<CharSequence> DESCRIPTOR =
     Option.valueOf("oracle.r2dbc.descriptor");