Java tutorial
package volker.streaming.music.gui; /* * #%L * NowPlaying * %% * Copyright (C) 2013 Volker Lanting * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program. If not, see * <http://www.gnu.org/licenses/gpl-3.0.html>. * #L% */ import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; import java.net.URL; import java.util.concurrent.atomic.AtomicBoolean; import javax.imageio.ImageIO; import javax.swing.BorderFactory; import javax.swing.GroupLayout; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.LayoutStyle; import javax.swing.border.Border; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.Consts; import volker.streaming.music.Config; import volker.streaming.music.Formatter; import volker.streaming.music.Track; import volker.streaming.music.lastfm.LastFmApi; import volker.streaming.music.lastfm.LastFmConfig; public class ApiPanel extends JPanel { private static final long serialVersionUID = 6183608388616105271L; private static final Log LOG = LogFactory.getLog(ApiPanel.class); private static final String RUNNING = "Running..."; private static final String STOPPED = "Stopped"; private AtomicBoolean status = new AtomicBoolean(false); private JButton statusButton; private Border textBorder; private Border iconBorder; private JLabel statusLabel; private JLabel stateLabel; private ImageIcon onIcon; private ImageIcon offIcon; private final Config config; private final LastFmConfig lastfmConfig; private final Formatter formatter; public ApiPanel(Config config, LastFmConfig lastfmConfig, Formatter formatter) { this.config = config; this.lastfmConfig = lastfmConfig; this.formatter = formatter; initComponents(); // FIXME keeps running until termination of jvm new Thread(new Poller()).start(); } private void initComponents() { URL onUrl = getClass().getResource("on.png"); onIcon = getIcon(onUrl); URL offUrl = getClass().getResource("off.png"); offIcon = getIcon(offUrl); statusButton = new JButton(); statusLabel = new JLabel("Start/Stop:"); stateLabel = new JLabel(status.get() ? RUNNING : STOPPED); iconBorder = BorderFactory.createEmptyBorder(); textBorder = statusButton.getBorder(); statusButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { synchronized (status) { // status is only set here status.set(!status.get()); } showUpdatedStatus(); } }); showUpdatedStatus(); GroupLayout layout = new GroupLayout(this); this.setLayout(layout); layout.setHorizontalGroup(layout.createSequentialGroup().addContainerGap() .addGroup(layout.createParallelGroup(GroupLayout.Alignment.CENTER) .addComponent(statusLabel, GroupLayout.Alignment.CENTER) .addComponent(statusButton, GroupLayout.Alignment.CENTER) .addComponent(stateLabel, GroupLayout.Alignment.CENTER)) .addContainerGap()); layout.setVerticalGroup(layout.createSequentialGroup().addContainerGap().addComponent(statusLabel) .addPreferredGap(LayoutStyle.ComponentPlacement.RELATED).addComponent(statusButton) .addPreferredGap(LayoutStyle.ComponentPlacement.RELATED).addComponent(stateLabel) .addContainerGap()); } private void showUpdatedStatus() { if (status.get()) { updateStatusButton(onIcon, "Currently running"); stateLabel.setText(RUNNING); } else { updateStatusButton(offIcon, "Currently stopped"); stateLabel.setText(STOPPED); } } // should be run on EDT private void updateStatusButton(ImageIcon icon, String backuptext) { if (icon == null) { statusButton.setText(backuptext); statusButton.setIcon(null); statusButton.setBorder(textBorder); } else { statusButton.setText(""); statusButton.setIcon(icon); statusButton.setBorder(iconBorder); } } private ImageIcon getIcon(URL url) { ImageIcon result = null; if (url == null) { LOG.error("Couldn't find image"); } else { try { result = new ImageIcon(ImageIO.read(url)); } catch (IOException e) { LOG.error("Couldn't read image " + url.toExternalForm(), e); } } return result; } private class Poller implements Runnable { private LastFmApi api; public Poller() { api = new LastFmApi(lastfmConfig); } @Override public void run() { while (true) { if (status.get()) { Track t = api.getNowPlaying(); File out = config.getOutputFile(); if (out != null && !out.isDirectory()) { if (!out.isFile()) { try { out.createNewFile(); } catch (SecurityException | IOException e) { LOG.error("Could not create outputfile", e); } } if (out.isFile()) { formatter.setNullMessage(config.getNoTrackMessage()); String content = formatter.format(t, config.getFormat()); OutputStreamWriter writer = null; try { writer = new OutputStreamWriter(new FileOutputStream(out, false), Consts.UTF_8); writer.write(content); writer.flush(); } catch (IOException e) { LOG.error("Failed to write track to file", e); } finally { try { if (writer != null) writer.close(); } catch (IOException e) { LOG.warn("Couldn't close filewriter", e); } } } else { LOG.warn("File " + out + "could not be created"); } } else { LOG.warn("Invalid output file " + out); } } try { Thread.sleep(lastfmConfig.getPollInterval() * 1000); } catch (InterruptedException e) { // time to continue I guess } } } } }