SOLR-8574: Implement ConnectionImpl.isValid() and DatabaseMetaDataImpl.getConnection()

solr/solrj/src/java/org/apache/solr/client/solrj/io/sql/ConnectionImpl.java

@@ -35,6 +35,8 @@ import java.sql.Struct;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 import org.apache.solr.client.solrj.impl.CloudSolrClient;
 import org.apache.solr.client.solrj.io.SolrClientCache;
@@ -290,7 +292,16 @@ class ConnectionImpl implements Connection {
 
   @Override
   public boolean isValid(int timeout) throws SQLException {
-    throw new UnsupportedOperationException();
+    // check that the connection isn't close and able to connect within the timeout
+    try {
+      if(!isClosed()) {
+        this.client.connect(timeout, TimeUnit.SECONDS);
+        return true;
+      }
+    } catch (InterruptedException|TimeoutException ignore) {
+      // Ignore error since connection is not valid
+    }
+    return false;
   }
 
   @Override

solr/solrj/src/java/org/apache/solr/client/solrj/io/sql/DatabaseMetaDataImpl.java

@@ -772,7 +772,7 @@ class DatabaseMetaDataImpl implements DatabaseMetaData {
 
   @Override
   public Connection getConnection() throws SQLException {
-    return null;
+    return this.connection;
   }
 
   @Override

solr/solrj/src/test/org/apache/solr/client/solrj/io/sql/JdbcTest.java

@@ -360,11 +360,13 @@ public class JdbcTest extends AbstractFullDistribZkTestBase {
     String sql = "select id, a_i, a_s, a_f as my_float_col from " + collection + " order by a_i desc limit 2";
 
     try (Connection con = DriverManager.getConnection(connectionString)) {
+      assertTrue(con.isValid(DEFAULT_CONNECTION_TIMEOUT));
       assertEquals(collection, con.getCatalog());
 
       DatabaseMetaData databaseMetaData = con.getMetaData();
       assertNotNull(databaseMetaData);
 
+      assertEquals(con, databaseMetaData.getConnection());
       assertEquals(connectionString, databaseMetaData.getURL());
 
       assertNull(con.getWarnings());