---
title: JavaのSwingWorkerをKotlinのCoroutinesに置き換える
author: aterai
pubdate: 2018-10-31T17:13:03+09:00
description: Java Swing の SwingWorker を Kotlin の Coroutines に置き換えるソースコードや build.gradle などのサンプル。
---
#contents

* 概要 [#summary]
[https://www.pushing-pixels.org/2018/08/07/replacing-swingworker-with-kotlin-coroutines.html Replacing SwingWorker with Kotlin coroutines ・ Pushing Pixels]を参考に、`Java Swing`の`SwingWorker`を`Kotlin`の`Coroutines`に置き換えるソースコードや`build.gradle`のサンプルなどについて記述、テストしています。

* ビルト [#build]
- 以下のバージョンを使用する`build.gradle`のサンプル
-- `kotlin 1.3.0`
-- `kotlinx.coroutines 1.0.0`

#code{{
group 'Example'
version '1.0-SNAPSHOT'

apply plugin: 'java'
// apply plugin: 'java'
apply plugin: 'kotlin'
apply plugin: 'application'

mainClassName = 'ExampleKt'

buildscript {
  ext.kotlin_version = '1.3.0'
  ext.coroutine_version = '1.0.0' // '0.30.2-eap13'
  // ext.kotlin_version = '1.3.0'
  // ext.coroutine_version = '1.0.0' // '0.30.2-eap13'
  repositories {
    mavenCentral()
  }
  dependencies {
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:latest.release"
  }
}

sourceCompatibility = 1.8
compileKotlin {
  kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
  kotlinOptions.jvmTarget = "1.8"
}

kotlin {
  repositories {
    mavenCentral()
  }
  dependencies {
    compile "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutine_version"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$coroutine_version"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-swing:$coroutine_version"
    compile "org.jetbrains.kotlinx:kotlinx-coroutines-core:latest.release"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:latest.release"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-swing:latest.release"
  }
}

repositories {
  mavenCentral()
}

dependencies {
  compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
  compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:latest.release"
}
}}

* サンプルコード [#sourcecode]
** `Java`(`SwingWorker`) [#s48c74fa]
#code{{
import java.awt.*;
import java.awt.geom.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import javax.swing.*;
import javax.swing.plaf.basic.BasicProgressBarUI;

public class MainPanel extends JPanel {
  protected final JProgressBar progress1 = new JProgressBar() {
    @Override public void updateUI() {
      super.updateUI();
      setUI(new ProgressCircleUI());
      setBorder(BorderFactory.createEmptyBorder(25, 25, 25, 25));
    }
  };
  protected final JProgressBar progress2 = new JProgressBar() {
    @Override public void updateUI() {
      super.updateUI();
      setUI(new ProgressCircleUI());
      setBorder(BorderFactory.createEmptyBorder(25, 25, 25, 25));
    }
  };
  public MainPanel() {
    super(new BorderLayout());
    progress1.setForeground(new Color(0xAAFFAAAA, true));
    progress2.setStringPainted(true);
    progress2.setFont(progress2.getFont().deriveFont(24f));

    JSlider slider = new JSlider();
    slider.putClientProperty("Slider.paintThumbArrowShape", Boolean.TRUE);
    progress1.setModel(slider.getModel());

    JButton button = new JButton("start");
    button.addActionListener(e -> {
      JButton b = (JButton) e.getSource();
      b.setEnabled(false);
      SwingWorker<String, Void> worker = new BackgroundTask() {
        @Override public void done() {
          if (b.isDisplayable()) {
            b.setEnabled(true);
          }
        }
      };
      worker.addPropertyChangeListener(new ProgressListener(progress2));
      worker.execute();
    });

    JPanel p = new JPanel(new GridLayout(1, 2));
    p.add(progress1);
    p.add(progress2);

    add(slider, BorderLayout.NORTH);
    add(p);
    add(button, BorderLayout.SOUTH);
    setPreferredSize(new Dimension(320, 240));
  }
  public static void main(String... args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGui();
      }
    });
  }
  public static void createAndShowGui() {
    try {
      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (ClassNotFoundException | InstantiationException
               | IllegalAccessException | UnsupportedLookAndFeelException ex) {
      ex.printStackTrace();
    }
    JFrame frame = new JFrame("@title@");
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    frame.getContentPane().add(new MainPanel());
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

class ProgressCircleUI extends BasicProgressBarUI {
  @Override public Dimension getPreferredSize(JComponent c) {
    Dimension d = super.getPreferredSize(c);
    int v = Math.max(d.width, d.height);
    d.setSize(v, v);
    return d;
  }
  @Override public void paint(Graphics g, JComponent c) {
    // public void paintDeterminate(Graphics g, JComponent c) {
    Insets b = progressBar.getInsets(); // area for border
    int barRectWidth = progressBar.getWidth() - b.right - b.left;
    int barRectHeight = progressBar.getHeight() - b.top - b.bottom;
    if (barRectWidth <= 0 || barRectHeight <= 0) {
      return;
    }

    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    double degree = 360 * progressBar.getPercentComplete();
    double sz = Math.min(barRectWidth, barRectHeight);
    double cx = b.left + barRectWidth * .5;
    double cy = b.top + barRectHeight * .5;
    double or = sz * .5;
    // double ir = or - 20;
    double ir = or * .5; // .8;
    Shape inner = new Ellipse2D.Double(cx - ir, cy - ir, ir * 2, ir * 2);
    Shape outer = new Ellipse2D.Double(cx - or, cy - or, sz, sz);
    Shape sector = new Arc2D.Double(cx - or, cy - or, sz, sz, 90 - degree, degree, Arc2D.PIE);

    Area foreground = new Area(sector);
    Area background = new Area(outer);
    Area hole = new Area(inner);

    foreground.subtract(hole);
    background.subtract(hole);

    // draw the track
    g2.setPaint(new Color(0xDDDDDD));
    g2.fill(background);

    // draw the circular sector
    // AffineTransform at = AffineTransform.getScaleInstance(-1.0, 1.0);
    // at.translate(-(barRectWidth + b.left * 2), 0);
    // AffineTransform at = AffineTransform.getRotateInstance(Math.toRadians(degree), cx, cy);
    // g2.fill(at.createTransformedShape(area));
    g2.setPaint(progressBar.getForeground());
    g2.fill(foreground);
    g2.dispose();

    // Deal with possible text painting
    if (progressBar.isStringPainted()) {
      paintString(g, b.left, b.top, barRectWidth, barRectHeight, 0, b);
    }
  }
}

class BackgroundTask extends SwingWorker<String, Void> {
  private final Random rnd = new Random();
  @Override public String doInBackground() {
    int current = 0;
    int lengthOfTask = 100;
    while (current <= lengthOfTask && !isCancelled()) {
      try { // dummy task
        Thread.sleep(rnd.nextInt(50) + 1);
      } catch (InterruptedException ex) {
        return "Interrupted";
      }
      setProgress(100 * current / lengthOfTask);
      current++;
    }
    return "Done";
  }
}

class ProgressListener implements PropertyChangeListener {
  private final JProgressBar progressBar;
  protected ProgressListener(JProgressBar progressBar) {
    this.progressBar = progressBar;
    this.progressBar.setValue(0);
  }
  @Override public void propertyChange(PropertyChangeEvent e) {
    String strPropertyName = e.getPropertyName();
    if ("progress".equals(strPropertyName)) {
      progressBar.setIndeterminate(false);
      int progress = (Integer) e.getNewValue();
      progressBar.setValue(progress);
    }
  }
}
}}

** `Kotlin`(`SwingWorker`版) [#xb3d6852]
#code(lang-kotlin){{
import java.awt.*
import java.awt.geom.*
import java.beans.PropertyChangeEvent
import java.beans.PropertyChangeListener
import java.util.Random
import javax.swing.*
import javax.swing.plaf.basic.BasicProgressBarUI

private fun makeUI(): Component {
  val progress = object : JProgressBar() {
    override fun updateUI() {
      super.updateUI()
      setUI(ProgressCircleUI())
      setBorder(BorderFactory.createEmptyBorder(25, 25, 25, 25))
    }
  }
  val button = JButton("start")
  button.addActionListener { e ->
    val b = e.getSource() as JButton
    b.setEnabled(false);
    val worker = object : BackgroundTask() {
      override fun done() {
        if (b.isDisplayable()) {
          b.setEnabled(true)
        }
      }
    }
    worker.addPropertyChangeListener(ProgressListener(progress))
    worker.execute()
  }

  return JPanel(BorderLayout(5, 5)).apply {
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5))
    add(progress)
    add(button, BorderLayout.SOUTH)
  }
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

internal class ProgressCircleUI : BasicProgressBarUI() {
  override fun getPreferredSize(c: JComponent): Dimension {
    val d = super.getPreferredSize(c)
    val v = Math.max(d.width, d.height)
    d.setSize(v, v)
    return d;
  }
  override fun paint(g: Graphics, c: JComponent) {
    val b = progressBar.getInsets(); // area for border
    val barRectWidth = progressBar.getWidth() - b.right - b.left
    val barRectHeight = progressBar.getHeight() - b.top - b.bottom
    if (barRectWidth <= 0 || barRectHeight <= 0) {
      return
    }

    val g2 = g.create() as Graphics2D
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)

    val degree = 360 * progressBar.getPercentComplete()
    val sz = 1.0 * Math.min(barRectWidth, barRectHeight)
    val cx = b.left + barRectWidth * .5
    val cy = b.top + barRectHeight * .5
    val or = sz * .5
    val ir = or * .5

    val inner = Ellipse2D.Double(cx - ir, cy - ir, ir * 2, ir * 2)
    val outer = Ellipse2D.Double(cx - or, cy - or, sz, sz)
    val sector = Arc2D.Double(cx - or, cy - or, sz, sz, 90 - degree, degree, Arc2D.PIE)

    val foreground = Area(sector)
    val background = Area(outer)
    val hole = Area(inner)

    foreground.subtract(hole)
    background.subtract(hole)

    // draw the track
    g2.setPaint(Color(0xDDDDDD))
    g2.fill(background)

    // draw the circular sector
    g2.setPaint(progressBar.getForeground())
    g2.fill(foreground)
    g2.dispose()

    // Deal with possible text painting
    if (progressBar.isStringPainted()) {
        paintString(g, b.left, b.top, barRectWidth, barRectHeight, 0, b)
    }
  }
}

open class BackgroundTask : SwingWorker<String, Void>() {
    private val rnd = Random()
    override fun doInBackground(): String {
        var current = 0
        val lengthOfTask = 100
        while (current <= lengthOfTask && !isCancelled()) {
            try { // dummy task
                Thread.sleep(1L + rnd.nextInt(50))
            } catch (ex: InterruptedException) {
                return "Interrupted"
            }
            setProgress(100 * current / lengthOfTask)
            current++
        }
        return "Done"
    }
}

internal class ProgressListener constructor(private val progressBar: JProgressBar) : PropertyChangeListener {
    init {
        this.progressBar.setValue(0)
    }
    override fun propertyChange(e: PropertyChangeEvent) {
        val strPropertyName = e.getPropertyName()
        if ("progress".equals(strPropertyName)) {
            progressBar.setIndeterminate(false)
            val progress = e.getNewValue() as Int
            progressBar.setValue(progress)
        }
    }
}
}}

** `Kotlin`(`Coroutine`版) [#qe13c59c]
#code(lang-kotlin){{
import java.awt.*
import java.awt.geom.Area
import java.awt.geom.Arc2D
import java.awt.geom.Ellipse2D
import javax.swing.*
import javax.swing.plaf.basic.BasicProgressBarUI

import kotlinx.coroutines.*
import kotlinx.coroutines.channels.*
import kotlinx.coroutines.swing.*

private fun makeUI(): Component {
  val progress = object : JProgressBar() {
    override fun updateUI() {
      super.updateUI()
      setUI(ProgressCircleUI())
      border = BorderFactory.createEmptyBorder(25, 25, 25, 25)
    }
  }
  val button = JButton("start")
  button.addActionListener { e ->
    GlobalScope.launch(Dispatchers.Swing) {
      val b = e.source as JButton
      b.isEnabled = false
      val channel = Channel<Int>()
      async {
        var current = 0
        val lengthOfTask = 100
        while (current <= lengthOfTask) {
          delay(20L)
          channel.send(100 * current / lengthOfTask)
          current++
        }
        // Close the channel as we're done processing
        channel.close()
      }
      // The next loop keeps on going as long as the channel is not closed
      for (y in channel) {
        // println("Processing $y " + SwingUtilities.isEventDispatchThread())
        progress.value = y
      }
      // status.text = "Done!"
      // @Override public void done() {
      if (b.isDisplayable) {
        b.isEnabled = true
      }
    }
  }
  return JPanel(BorderLayout(5, 5)).apply {
    border = BorderFactory.createEmptyBorder(5, 5, 5, 5)
    add(progress)
    add(button, BorderLayout.SOUTH)
  }
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      isVisible = true
    }
  }
}

internal class ProgressCircleUI : BasicProgressBarUI() {
  override fun getPreferredSize(c: JComponent): Dimension {
    val d = super.getPreferredSize(c)
    val v = Math.max(d.width, d.height)
    d.setSize(v, v)
    return d
  }
  override fun paint(g: Graphics, c: JComponent) {
    val b = progressBar.insets // area for border
    val barRectWidth = progressBar.width - b.right - b.left
    val barRectHeight = progressBar.height - b.top - b.bottom
    if (barRectWidth <= 0 || barRectHeight <= 0) {
      return
    }

    val g2 = g.create() as Graphics2D
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)

    val degree = 360 * progressBar.percentComplete
    val sz = 1.0 * Math.min(barRectWidth, barRectHeight)
    val cx = b.left + barRectWidth * .5
    val cy = b.top + barRectHeight * .5
    val or = sz * .5
    val ir = or * .5

    val inner = Ellipse2D.Double(cx - ir, cy - ir, ir * 2, ir * 2)
    val outer = Ellipse2D.Double(cx - or, cy - or, sz, sz)
    val sector = Arc2D.Double(cx - or, cy - or, sz, sz, 90 - degree, degree, Arc2D.PIE)

    val foreground = Area(sector)
    val background = Area(outer)
    val hole = Area(inner)

    foreground.subtract(hole)
    background.subtract(hole)

    // draw the track
    g2.paint = Color(0xDDDDDD)
    g2.fill(background)

    // draw the circular sector
    g2.paint = progressBar.foreground
    g2.fill(foreground)
    g2.dispose()

    // Deal with possible text painting
    if (progressBar.isStringPainted) {
      paintString(g, b.left, b.top, barRectWidth, barRectHeight, 0, b)
    }
  }
}
}}

* 解説 [#explanation]
- `Java`版は[[JProgressBarの進捗状況を円形で表示する>Swing/ProgressCircle]]とほぼ同一なので、コンパイル、実行なども同様の方法で可能
- `Kotlin`版の実行方法
-- `OpenJDK 1.8.0_192`などをインストール
-- `sdkman`などで`kotlin 1.3.0`、`gralde 4.10.2`などをインストール
-- 適当なディレクトリを作成して、上記の`build.gradle`、`src/main/kotlin/Example.kt`を配置
- 作成したディレクトリで、`gradle run`を実行

* 参考リンク [#reference]
- [https://www.pushing-pixels.org/2018/08/07/replacing-swingworker-with-kotlin-coroutines.html Replacing SwingWorker with Kotlin coroutines ・ Pushing Pixels]
- [https://github.com/Kotlin/kotlinx.coroutines/blob/master/COMPATIBILITY.md#migration-to-100-version-with-kotlin-13 kotlinx.coroutines/COMPATIBILITY.md at master · Kotlin/kotlinx.coroutines]
- [https://github.com/Kotlin/kotlinx.coroutines/blob/master/ui/coroutines-guide-ui.md kotlinx.coroutines/coroutines-guide-ui.md at master · Kotlin/kotlinx.coroutines]
- [[JProgressBarの進捗状況を円形で表示する>Swing/ProgressCircle]]
- [http://d.hatena.ne.jp/nowokay/20180809#1533777641 Project LoomでJavaでの継続(Continuation)を試す - きしだのはてな]

* コメント [#comment]
#comment
#comment