ScalaでSwing ファイルを開く・保存

ScalaSwingFile.scala

// ScalaでSwing ファイルを開く・保存

import scala.swing._
import scala.swing.event.ButtonClicked
import java.io.{ File, IOException }
import java.awt.Font
import javax.swing.{ UIManager, SwingUtilities }
import javax.swing.filechooser.FileNameExtensionFilter
import org.apache.commons.lang.SystemUtils
import org.apache.commons.io.FileUtils

object ScalaSwingFile extends SimpleGUIApplication {
  val monoFont = new Font("monospaced", Font.PLAIN, 14)
  var currentFile: File = null

  val mainPanel = new BoxPanel(Orientation.Vertical) {
    val buttonPanel = new BoxPanel(Orientation.Horizontal) {
      val openButton = new Button { text = "開く" }
      val saveButton = new Button { text = "上書き保存" }
      val saveAsButton = new Button { text = "名前を付けて保存" }
      contents += openButton
      contents += saveButton
      contents += saveAsButton
    }

    val editScroll = new ScrollPane {
      preferredSize = (600, 400)
      val editArea = new TextArea { font = monoFont }
      contents = editArea
    }
    contents += buttonPanel
    contents += editScroll

    listenTo(buttonPanel.openButton)
    listenTo(buttonPanel.saveButton)
    listenTo(buttonPanel.saveAsButton)

    def getFileChooser = {
      val dir = if (currentFile == null) SystemUtils.getUserDir else currentFile
      new FileChooser(dir) {
        fileFilter = new FileNameExtensionFilter("テキストファイル", "txt")
        fileFilter = new FileNameExtensionFilter("Scala / Ruby", "scala", "rb")
        //TODO FileChooser#accessory= / JFileChooser#setAccessory
      }
    }
    def openFile: Unit = {
      val fc = getFileChooser
      fc.title = "ファイルを開く"
      fc.showOpenDialog(this) match {
        case FileChooser.Result.Approve =>
          try {
            if (fc.selectedFile.exists) {
              editScroll.editArea.text = FileUtils.readFileToString(fc.selectedFile)
              currentFile = fc.selectedFile
            } else {
              editScroll.editArea.text = ""
              currentFile = fc.selectedFile
            }
          } catch {
            case e: IOException =>
              Dialog.showMessage(this, "ファイルを開けませんでした。\n" + e.getMessage)
          }
        case FileChooser.Result.Cancel => ;
        case FileChooser.Result.Error => ;
      }
    }
    def saveFile(f: File): Unit = {
      try {
        FileUtils.writeStringToFile(f, editScroll.editArea.text)
      } catch {
        case e: IOException =>
          Dialog.showMessage(this, "ファイルを保存できませんでした。\n" + e.getMessage)
      }
    }
    def saveAsFile: Unit = {
      val fc = getFileChooser
      fc.title = "名前を付けて保存"
      fc.showSaveDialog(this) match {
        case FileChooser.Result.Approve =>
          val sf = fc.selectedFile
          val confResult = if (sf.exists) {
            Dialog.showConfirmation(this,
              sf.getName + " は既に存在します。\n上書きしますか？",
              "名前を付けて保存の確認", Dialog.Options.YesNo)
          } else {
            Dialog.Result.Yes
          }
          if (confResult == Dialog.Result.Yes) {
            try {
              FileUtils.writeStringToFile(sf, editScroll.editArea.text)
              currentFile = sf
            } catch {
              case e: IOException =>
                Dialog.showMessage(this, "ファイルを保存できませんでした。\n" + e.getMessage)
            }
          }
        case FileChooser.Result.Cancel => ;
        case FileChooser.Result.Error => ;
      }
    }

    reactions += {
      case ButtonClicked(buttonPanel.openButton) => openFile
      case ButtonClicked(buttonPanel.saveButton) =>
        currentFile match {
          case f: File => saveFile(f)
          case null => saveAsFile;
        }
      case ButtonClicked(buttonPanel.saveAsButton) => saveAsFile
    }
  }

  def top = new MainFrame {
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName())
    SwingUtilities.updateComponentTreeUI(mainPanel.peer)
    title = "ScalaでSwing ファイルを開く・保存"
    contents = mainPanel
  }
}