[SPARK-15234][SQL] Fix spark.catalog.listDatabases.show()

## What changes were proposed in this pull request?

Before:
```
scala> spark.catalog.listDatabases.show()
+--------------------+-----------+-----------+
|                name|description|locationUri|
+--------------------+-----------+-----------+
|Database[name='de...|
|Database[name='my...|
|Database[name='so...|
+--------------------+-----------+-----------+
```

After:
```
+-------+--------------------+--------------------+
|   name|         description|         locationUri|
+-------+--------------------+--------------------+
|default|Default Hive data...|file:/user/hive/w...|
|  my_db|  This is a database|file:/Users/andre...|
|some_db|                    |file:/private/var...|
+-------+--------------------+--------------------+
```

## How was this patch tested?

New test in `CatalogSuite`

Author: Andrew Or <andrew@databricks.com>

Closes #13015 from andrewor14/catalog-show.

1 files changed, 9 insertions, 1 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
index d158a64a85..79bb7a701b 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
@@ -17,7 +17,6 @@
 
 package org.apache.spark.sql.catalyst
 
-import org.apache.spark.SparkException
 import org.apache.spark.sql.catalyst.analysis.{UnresolvedAttribute, UnresolvedExtractValue}
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.util.{ArrayBasedMapData, DateTimeUtils, GenericArrayData}
@@ -659,6 +658,15 @@ object ScalaReflection extends ScalaReflection {
     constructParams(t).map(_.name.toString)
   }
 
+  /**
+   * Returns the parameter values for the primary constructor of this class.
+   */
+  def getConstructorParameterValues(obj: DefinedByConstructorParams): Seq[AnyRef] = {
+    getConstructorParameterNames(obj.getClass).map { name =>
+      obj.getClass.getMethod(name).invoke(obj)
+    }
+  }
+
   /*
    * Retrieves the runtime class corresponding to the provided type.
    */