Github user liancheng commented on a diff in the pull request:
https://github.com/apache/spark/pull/5498#discussion_r28403924
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/jdbc/DriverQuirks.scala ---
@@ -39,33 +39,70 @@ import java.sql.Types
* if `getJDBCType` returns `(null, None)`, the default type handling is
used
* for the given Catalyst type.
*/
-private[sql] abstract class DriverQuirks {
+abstract class DriverQuirks {
+ def canHandle(url : String): Boolean
def getCatalystType(sqlType: Int, typeName: String, size: Int, md:
MetadataBuilder): DataType
def getJDBCType(dt: DataType): (String, Option[Int])
}
-private[sql] object DriverQuirks {
+object DriverQuirks {
+
+ private var quirks = List[DriverQuirks]()
+
+ def registerQuirks(quirk: DriverQuirks) {
+ quirks = quirk :: quirks
+ }
+
+ def unregisterQuirks(quirk : DriverQuirks) {
+ quirks = quirks.filterNot(_ == quirk)
+ }
+
+ registerQuirks(new MySQLQuirks())
+ registerQuirks(new PostgresQuirks())
+
/**
* Fetch the DriverQuirks class corresponding to a given database url.
*/
def get(url: String): DriverQuirks = {
- if (url.substring(0, 10).equals("jdbc:mysql")) {
- new MySQLQuirks()
- } else if (url.substring(0, 15).equals("jdbc:postgresql")) {
- new PostgresQuirks()
- } else {
- new NoQuirks()
+ val matchingQuirks = quirks.filter(_.canHandle(url))
+ matchingQuirks.length match {
+ case 0 => new NoQuirks()
+ case 1 => matchingQuirks.head
+ case _ => new AggregatedQuirks(matchingQuirks)
}
}
}
-private[sql] class NoQuirks extends DriverQuirks {
+class AggregatedQuirks(quirks: List[DriverQuirks]) extends DriverQuirks {
+ def canHandle(url : String): Boolean =
+ quirks.foldLeft(true)((l,r) => l && r.canHandle(url))
+ def getCatalystType(sqlType: Int, typeName: String, size: Int, md:
MetadataBuilder) : DataType =
+ quirks.foldLeft(null.asInstanceOf[DataType])((l,r) =>
+ if (l != null) {
+ l
+ } else {
+ r.getCatalystType(sqlType, typeName, size, md)
+ }
+ )
+ def getJDBCType(dt: DataType): (String, Option[Int]) =
+ quirks.foldLeft(null.asInstanceOf[(String, Option[Int])])((l,r) =>
+ if (l != null) {
+ l
+ } else {
+ r.getJDBCType(dt)
+ }
+ )
--- End diff --
Both `l` and `r` are always non-null pairs. Only `l._1` and `r._1` are
possible to be null.
```scala
quirks.map(_.getJDBCType(dt)).collectFirst {
case p @ (typeName, _) if typeName != null => p
}.getOrElse((null, None))
```
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