How do I configure the Column names in a Scala Table? - scala

Question

I am writing a Scala program to manage a database, and have drawn all of the data into a 2-dimensional ArrayBuffer where row 0 is the column names, and the subsequent rows contain the info for each entry in the table.
When trying to put this into a Table, ho=w do I go about assigning the Column headers?
Syntax suggestions would be greatly appreciated.
Pseudocode:
Data=ArrayBuffer()
Data(0)={"Name","Birthday","ID"}
Data(1)={"Bob", "07/19/1986", "2354"}
Data(2)={"Sue", "05/07/1980", "2355"}
Data(3)={"Joe", "08/12/1992", "2356"}
Data(4)={"Jim", "11/20/1983", "2357"}
I want to put this into a Table where Data(0) describes the column headers, and the subsequent rows describe rows in the table, but I can't figure out how to set the row headers.

Answer 1

The easiest way to put data in a Table is to use its constructor:
new Table (rowData: Array[Array[Any]], columnNames: Seq[_])
The slightly tricky thing here is that arrays are not covariant (see Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?), which means that an Array[String] is not a subtype of Array[Any]. So you need some way of turning one into the other: a map does the job.
Also, for the column names to show, you need to put the table in a ScrollPane.
import swing._
import collection.mutable.ArrayBuffer
object Demo extends SimpleSwingApplication {
val data = ArrayBuffer(
Array("Name","Birthday","ID"),
Array("Bob", "07/19/1986", "2354"),
Array("Sue", "05/07/1980", "2355")
)
def top = new MainFrame {
contents = new ScrollPane {
contents = new Table(
data.tail.toArray map (_.toArray[Any]),
data.head
)
}
}
}
Will give you a table:
Edit: you can also use a cast: data.tail.toArray.asInstanceOf[Array[Array[Any]]], which is more efficient than mapping.

Answer 2

assuming you are talking of swing, if you put your table inside a scrollpane and create your table model based on the array buffer shown, the first row will be taken as column names by default.