[KYUUBI #2540] Kyuubi Spark TPC-DS Connector - SupportsNamespaces

### _Why are the changes needed?_

fix #2540

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [ ] [Run test](https://kyuubi.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #2649 from jiaoqingbo/kyuubi2540.

Closes #2540

f64150d [jiaoqingbo] code review
9faff90 [jiaoqingbo] [KYUUBI #2540] Kyuubi Spark TPC-DS Connector - SupportsNamespaces

Authored-by: jiaoqingbo <1178404354@qq.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: jiaoqingbo

extensions/spark/kyuubi-spark-connector-tpcds/src/main/scala/org/apache/kyuubi/spark/connector/tpcds/TPCDSCatalog.scala

@@ -20,16 +20,16 @@ package org.apache.kyuubi.spark.connector.tpcds
 import java.util
 
 import scala.collection.JavaConverters._
+import scala.collection.immutable
 
 import io.trino.tpcds.Table
 import org.apache.spark.sql.catalyst.analysis.{NoSuchNamespaceException, NoSuchTableException}
-import org.apache.spark.sql.connector.catalog.{Identifier, Table => SparkTable, TableCatalog, TableChange}
+import org.apache.spark.sql.connector.catalog.{Identifier, NamespaceChange, SupportsNamespaces, Table => SparkTable, TableCatalog, TableChange}
 import org.apache.spark.sql.connector.expressions.Transform
 import org.apache.spark.sql.types.StructType
 import org.apache.spark.sql.util.CaseInsensitiveStringMap
 
-// TODO: implement SupportsNamespaces
-class TPCDSCatalog extends TableCatalog {
+class TPCDSCatalog extends TableCatalog with SupportsNamespaces {
 
   val tables: Array[String] = Table.getBaseTables.asScala
     .map(_.getName).filterNot(_ == "dbgen_version").toArray
@@ -72,4 +72,37 @@ class TPCDSCatalog extends TableCatalog {
 
   override def renameTable(oldIdent: Identifier, newIdent: Identifier): Unit =
     throw new UnsupportedOperationException
+
+  override def listNamespaces(): Array[Array[String]] = {
+    databases.map(Array(_))
+  }
+
+  override def listNamespaces(namespace: Array[String]): Array[Array[String]] = {
+    namespace match {
+      case Array() =>
+        listNamespaces()
+      case Array(db) if databases contains db =>
+        Array()
+      case _ =>
+        throw new NoSuchNamespaceException(namespace)
+    }
+  }
+
+  override def loadNamespaceMetadata(namespace: Array[String]): util.Map[String, String] = {
+    namespace match {
+      case Array(_) =>
+        immutable.HashMap[String, String]().asJava
+      case _ =>
+        throw new NoSuchNamespaceException(namespace)
+    }
+  }
+
+  override def createNamespace(namespace: Array[String], metadata: util.Map[String, String]): Unit =
+    throw new UnsupportedOperationException
+
+  override def alterNamespace(namespace: Array[String], changes: NamespaceChange*): Unit =
+    throw new UnsupportedOperationException
+
+  override def dropNamespace(namespace: Array[String]): Boolean =
+    throw new UnsupportedOperationException
 }

extensions/spark/kyuubi-spark-connector-tpcds/src/test/scala/org/apache/kyuubi/spark/connector/tpcds/TPCDSCatalogSuite.scala

@@ -32,6 +32,12 @@ class TPCDSCatalogSuite extends KyuubiFunSuite {
       .getOrCreate()
   }
 
+  test("supports namespaces") {
+    spark.sql("use tpcds")
+    assert(spark.sql(s"SHOW DATABASES").collect().length == 10)
+    assert(spark.sql(s"SHOW NAMESPACES IN tpcds.sf1").collect().length == 0)
+  }
+
   test("tpcds.sf1 count") {
     assert(spark.table("tpcds.sf1.call_center").count === 6)
     assert(spark.table("tpcds.sf1.catalog_page").count === 11718)