Scala: how to implement Java class with more constructors

Question

I have searched for hours, but I did not found a solution:

I want to implement a Scala class that extends a Java class that has different constructors:

The Java class (JGoodies):

public abstract class AbstractTableAdapter<E> 
    extends AbstractTableModel implements ListModelBindable

The constructors:

AbstractTableAdapter()
AbstractTableAdapter(ListModel listModel)
AbstractTableAdapter(String... columnNames)
AbstractTableAdapter(ListModel listModel, String... columnNames)

The ListModel is a generic interface if that matters:

public interface ListModel<E>

I tried in Scala 2.11:

class LibraryListTableModel(listModel: SelectionInList[Book], columnNames: Array[String]) extends AbstractTableAdapter[Book](listModel, columnNames) {
    def this() = this(null, null)
    def this(listModel: SelectionInList[Book]) = this(null, null)
    def this(columnNames: Array[String]) = this(null, null)
}

but that gives this error message:

error: overloaded method constructor AbstractTableAdapter with alternatives:
[INFO]   (x$1: javax.swing.ListModel[_],x$2: String*)com.jgoodies.binding.adapter.AbstractTableAdapter[eu.eyan.idakonyvtar.model.Book] <and>
[INFO]   (x$1: String*)com.jgoodies.binding.adapter.AbstractTableAdapter[eu.eyan.idakonyvtar.model.Book]
[INFO]  cannot be applied to (com.jgoodies.binding.list.SelectionInList[eu.eyan.idakonyvtar.model.Book], Array[String])
[INFO]     extends AbstractTableAdapter[Book](listModel, columnNames) {
[INFO]             ^
[ERROR] one error found

I think the String... causes the problem.. Is it possible to extend such an abstract class? Thanks: András

Rich Henry · Accepted Answer · 2015-09-19 16:24:22Z

3

You can destructure in the incoming array into its various elements for the vararg by using the : _* syntax, i.e.:

case class Base(strs: String*) {  }
class Sub(ary: Array[String]) extends Base(ary:_*) { }

EDIT: Note, that WrappedArray (the result of the vararg) extends ArrayLike but I don't believe it's an Array.

edited Sep 19, 2015 at 16:24

answered Sep 19, 2015 at 16:18

Rich Henry

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Andras · Accepted Answer · 2015-09-19 18:07:41Z

0

The solution was indeed marking the String... parameter with :_*

class LibraryListTableModel(listModel: SelectionInList[Book], columnNames: String*) extends AbstractTableAdapter[Book](listModel, columnNames: _*) {...}

This post helped too: http://daily-scala.blogspot.de/2009/11/varargs.html

answered Sep 19, 2015 at 18:07

Andras

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