Beispiel #1
0
  /**
   * Create preview component.
   *
   * @param type type
   * @param comboBox the options.
   * @param prefSize the preferred size
   * @return the component.
   */
  private static Component createPreview(int type, final JComboBox comboBox, Dimension prefSize) {
    JComponent preview = null;

    if (type == DeviceConfigurationComboBoxModel.AUDIO) {
      Object selectedItem = comboBox.getSelectedItem();

      if (selectedItem instanceof AudioSystem) {
        AudioSystem audioSystem = (AudioSystem) selectedItem;

        if (!NoneAudioSystem.LOCATOR_PROTOCOL.equalsIgnoreCase(audioSystem.getLocatorProtocol())) {
          preview = new TransparentPanel(new GridBagLayout());
          createAudioSystemControls(audioSystem, preview);
        }
      }
    } else if (type == DeviceConfigurationComboBoxModel.VIDEO) {
      JLabel noPreview =
          new JLabel(
              NeomediaActivator.getResources().getI18NString("impl.media.configform.NO_PREVIEW"));

      noPreview.setHorizontalAlignment(SwingConstants.CENTER);
      noPreview.setVerticalAlignment(SwingConstants.CENTER);

      preview = createVideoContainer(noPreview);
      preview.setPreferredSize(prefSize);

      Object selectedItem = comboBox.getSelectedItem();
      CaptureDeviceInfo device = null;
      if (selectedItem instanceof DeviceConfigurationComboBoxModel.CaptureDevice)
        device = ((DeviceConfigurationComboBoxModel.CaptureDevice) selectedItem).info;

      Exception exception;
      try {
        createVideoPreview(device, preview);
        exception = null;
      } catch (IOException ex) {
        exception = ex;
      } catch (MediaException ex) {
        exception = ex;
      }
      if (exception != null) {
        logger.error("Failed to create preview for device " + device, exception);
        device = null;
      }
    }

    return preview;
  }
Beispiel #2
0
 private void loadStates() {
   boolean b = enableDefaultEncryption.isSelected();
   cboSavpOption.setEnabled(b);
   this.encryptionProtocolPreferences.setEnabled(b);
   enableSipZrtpAttribute.setEnabled(
       b && this.encryptionConfigurationTableModel.isEnabledLabel("ZRTP"));
   tabCiphers.setEnabled(b && this.encryptionConfigurationTableModel.isEnabledLabel("SDES"));
 }
Beispiel #3
0
  /**
   * Saves the user input when the "Next" wizard buttons is clicked.
   *
   * @param registration the SIPAccountRegistration
   * @return
   */
  public boolean commitPanel(SecurityAccountRegistration registration) {
    registration.setDefaultEncryption(enableDefaultEncryption.isSelected());
    registration.setEncryptionProtocols(encryptionConfigurationTableModel.getEncryptionProtocols());
    registration.setEncryptionProtocolStatus(
        encryptionConfigurationTableModel.getEncryptionProtocolStatus());
    registration.setSipZrtpAttribute(enableSipZrtpAttribute.isSelected());
    registration.setSavpOption(((SavpOption) cboSavpOption.getSelectedItem()).option);
    registration.setSDesCipherSuites(cipherModel.getEnabledCiphers());

    return true;
  }
  /**
   * Creates an instance of <tt>SelectScreenDialog</tt> by specifying the list of possible desktop
   * devices to choose from.
   *
   * @param desktopDevices the list of possible desktop devices to choose from
   */
  public SelectScreenDialog(List<MediaDevice> desktopDevices) {
    setModal(true);

    setPreferredSize(new Dimension(400, 300));

    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());

    deviceComboBox = new JComboBox(desktopDevices.toArray());
    contentPane.add(deviceComboBox, BorderLayout.NORTH);

    deviceComboBox.setRenderer(new ComboRenderer());

    contentPane.add(createPreview(deviceComboBox));

    contentPane.add(createButtonsPanel(), BorderLayout.SOUTH);
  }
Beispiel #5
0
  /**
   * Loads the account with the given identifier.
   *
   * @param accountID the account identifier
   */
  public void loadAccount(AccountID accountID) {
    enableDefaultEncryption.setSelected(
        accountID.getAccountPropertyBoolean(ProtocolProviderFactory.DEFAULT_ENCRYPTION, true));

    Map<String, Integer> encryptionProtocols =
        accountID.getIntegerPropertiesByPrefix(ProtocolProviderFactory.ENCRYPTION_PROTOCOL, true);
    Map<String, Boolean> encryptionProtocolStatus =
        accountID.getBooleanPropertiesByPrefix(
            ProtocolProviderFactory.ENCRYPTION_PROTOCOL_STATUS, true, false);
    this.loadEncryptionProtocols(encryptionProtocols, encryptionProtocolStatus);

    enableSipZrtpAttribute.setSelected(
        accountID.getAccountPropertyBoolean(
            ProtocolProviderFactory.DEFAULT_SIPZRTP_ATTRIBUTE, true));
    cboSavpOption.setSelectedIndex(
        accountID.getAccountPropertyInt(
            ProtocolProviderFactory.SAVP_OPTION, ProtocolProviderFactory.SAVP_OFF));
    cipherModel.loadData(
        accountID.getAccountPropertyString(ProtocolProviderFactory.SDES_CIPHER_SUITES));
    loadStates();
  }
Beispiel #6
0
  private static void createAudioPreview(
      final AudioSystem audioSystem,
      final JComboBox comboBox,
      final SoundLevelIndicator soundLevelIndicator) {
    final ActionListener captureComboActionListener =
        new ActionListener() {
          private final SimpleAudioLevelListener audioLevelListener =
              new SimpleAudioLevelListener() {
                public void audioLevelChanged(int level) {
                  soundLevelIndicator.updateSoundLevel(level);
                }
              };

          private AudioMediaDeviceSession deviceSession;

          private final BufferTransferHandler transferHandler =
              new BufferTransferHandler() {
                public void transferData(PushBufferStream stream) {
                  try {
                    stream.read(transferHandlerBuffer);
                  } catch (IOException ioe) {
                  }
                }
              };

          private final Buffer transferHandlerBuffer = new Buffer();

          public void actionPerformed(ActionEvent event) {
            setDeviceSession(null);

            CaptureDeviceInfo cdi;

            if (comboBox == null) {
              cdi = soundLevelIndicator.isShowing() ? audioSystem.getCaptureDevice() : null;
            } else {
              Object selectedItem =
                  soundLevelIndicator.isShowing() ? comboBox.getSelectedItem() : null;

              cdi =
                  (selectedItem instanceof DeviceConfigurationComboBoxModel.CaptureDevice)
                      ? ((DeviceConfigurationComboBoxModel.CaptureDevice) selectedItem).info
                      : null;
            }

            if (cdi != null) {
              for (MediaDevice md : mediaService.getDevices(MediaType.AUDIO, MediaUseCase.ANY)) {
                if (md instanceof AudioMediaDeviceImpl) {
                  AudioMediaDeviceImpl amd = (AudioMediaDeviceImpl) md;

                  if (cdi.equals(amd.getCaptureDeviceInfo())) {
                    try {
                      MediaDeviceSession deviceSession = amd.createSession();
                      boolean setDeviceSession = false;

                      try {
                        if (deviceSession instanceof AudioMediaDeviceSession) {
                          setDeviceSession((AudioMediaDeviceSession) deviceSession);
                          setDeviceSession = true;
                        }
                      } finally {
                        if (!setDeviceSession) deviceSession.close();
                      }
                    } catch (Throwable t) {
                      if (t instanceof ThreadDeath) throw (ThreadDeath) t;
                    }
                    break;
                  }
                }
              }
            }
          }

          private void setDeviceSession(AudioMediaDeviceSession deviceSession) {
            if (this.deviceSession == deviceSession) return;

            if (this.deviceSession != null) {
              try {
                this.deviceSession.close();
              } finally {
                this.deviceSession.setLocalUserAudioLevelListener(null);
                soundLevelIndicator.resetSoundLevel();
              }
            }

            this.deviceSession = deviceSession;

            if (this.deviceSession != null) {
              this.deviceSession.setContentDescriptor(new ContentDescriptor(ContentDescriptor.RAW));
              this.deviceSession.setLocalUserAudioLevelListener(audioLevelListener);
              this.deviceSession.start(MediaDirection.SENDONLY);

              try {
                DataSource dataSource = this.deviceSession.getOutputDataSource();

                dataSource.connect();

                PushBufferStream[] streams = ((PushBufferDataSource) dataSource).getStreams();

                for (PushBufferStream stream : streams) stream.setTransferHandler(transferHandler);

                dataSource.start();
              } catch (Throwable t) {
                if (t instanceof ThreadDeath) throw (ThreadDeath) t;
                else setDeviceSession(null);
              }
            }
          }
        };

    if (comboBox != null) comboBox.addActionListener(captureComboActionListener);

    soundLevelIndicator.addHierarchyListener(
        new HierarchyListener() {
          public void hierarchyChanged(HierarchyEvent event) {
            if ((event.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
              SwingUtilities.invokeLater(
                  new Runnable() {
                    public void run() {
                      captureComboActionListener.actionPerformed(null);
                    }
                  });
            }
          }
        });
  }
Beispiel #7
0
  /**
   * Creates the video advanced settings.
   *
   * @return video advanced settings panel.
   */
  private static Component createVideoAdvancedSettings() {
    ResourceManagementService resources = NeomediaActivator.getResources();

    final DeviceConfiguration deviceConfig = mediaService.getDeviceConfiguration();

    TransparentPanel centerPanel = new TransparentPanel(new GridBagLayout());
    centerPanel.setMaximumSize(new Dimension(WIDTH, 150));

    JButton resetDefaultsButton =
        new JButton(resources.getI18NString("impl.media.configform.VIDEO_RESET"));
    JPanel resetButtonPanel = new TransparentPanel(new FlowLayout(FlowLayout.RIGHT));
    resetButtonPanel.add(resetDefaultsButton);

    final JPanel centerAdvancedPanel = new TransparentPanel(new BorderLayout());
    centerAdvancedPanel.add(centerPanel, BorderLayout.NORTH);
    centerAdvancedPanel.add(resetButtonPanel, BorderLayout.SOUTH);

    GridBagConstraints constraints = new GridBagConstraints();
    constraints.fill = GridBagConstraints.HORIZONTAL;
    constraints.anchor = GridBagConstraints.NORTHWEST;
    constraints.insets = new Insets(5, 5, 0, 0);
    constraints.gridx = 0;
    constraints.weightx = 0;
    constraints.weighty = 0;
    constraints.gridy = 0;

    centerPanel.add(
        new JLabel(resources.getI18NString("impl.media.configform.VIDEO_RESOLUTION")), constraints);
    constraints.gridy = 1;
    constraints.insets = new Insets(0, 0, 0, 0);
    final JCheckBox frameRateCheck =
        new SIPCommCheckBox(resources.getI18NString("impl.media.configform.VIDEO_FRAME_RATE"));
    centerPanel.add(frameRateCheck, constraints);
    constraints.gridy = 2;
    constraints.insets = new Insets(5, 5, 0, 0);
    centerPanel.add(
        new JLabel(resources.getI18NString("impl.media.configform.VIDEO_PACKETS_POLICY")),
        constraints);

    constraints.weightx = 1;
    constraints.gridx = 1;
    constraints.gridy = 0;
    constraints.insets = new Insets(5, 0, 0, 5);
    Object[] resolutionValues = new Object[DeviceConfiguration.SUPPORTED_RESOLUTIONS.length + 1];
    System.arraycopy(
        DeviceConfiguration.SUPPORTED_RESOLUTIONS,
        0,
        resolutionValues,
        1,
        DeviceConfiguration.SUPPORTED_RESOLUTIONS.length);
    final JComboBox sizeCombo = new JComboBox(resolutionValues);
    sizeCombo.setRenderer(new ResolutionCellRenderer());
    sizeCombo.setEditable(false);
    centerPanel.add(sizeCombo, constraints);

    // default value is 20
    final JSpinner frameRate = new JSpinner(new SpinnerNumberModel(20, 5, 30, 1));
    frameRate.addChangeListener(
        new ChangeListener() {
          public void stateChanged(ChangeEvent e) {
            deviceConfig.setFrameRate(
                ((SpinnerNumberModel) frameRate.getModel()).getNumber().intValue());
          }
        });
    constraints.gridy = 1;
    constraints.insets = new Insets(0, 0, 0, 5);
    centerPanel.add(frameRate, constraints);

    frameRateCheck.addActionListener(
        new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            if (frameRateCheck.isSelected()) {
              deviceConfig.setFrameRate(
                  ((SpinnerNumberModel) frameRate.getModel()).getNumber().intValue());
            } else // unlimited framerate
            deviceConfig.setFrameRate(-1);

            frameRate.setEnabled(frameRateCheck.isSelected());
          }
        });

    final JSpinner videoMaxBandwidth =
        new JSpinner(
            new SpinnerNumberModel(deviceConfig.getVideoMaxBandwidth(), 1, Integer.MAX_VALUE, 1));
    videoMaxBandwidth.addChangeListener(
        new ChangeListener() {
          public void stateChanged(ChangeEvent e) {
            deviceConfig.setVideoMaxBandwidth(
                ((SpinnerNumberModel) videoMaxBandwidth.getModel()).getNumber().intValue());
          }
        });
    constraints.gridx = 1;
    constraints.gridy = 2;
    constraints.insets = new Insets(0, 0, 5, 5);
    centerPanel.add(videoMaxBandwidth, constraints);

    resetDefaultsButton.addActionListener(
        new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            // reset to defaults
            sizeCombo.setSelectedIndex(0);
            frameRateCheck.setSelected(false);
            frameRate.setEnabled(false);
            frameRate.setValue(20);
            // unlimited framerate
            deviceConfig.setFrameRate(-1);
            videoMaxBandwidth.setValue(DeviceConfiguration.DEFAULT_VIDEO_MAX_BANDWIDTH);
          }
        });

    // load selected value or auto
    Dimension videoSize = deviceConfig.getVideoSize();

    if ((videoSize.getHeight() != DeviceConfiguration.DEFAULT_VIDEO_HEIGHT)
        && (videoSize.getWidth() != DeviceConfiguration.DEFAULT_VIDEO_WIDTH))
      sizeCombo.setSelectedItem(deviceConfig.getVideoSize());
    else sizeCombo.setSelectedIndex(0);
    sizeCombo.addActionListener(
        new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            Dimension selectedVideoSize = (Dimension) sizeCombo.getSelectedItem();

            if (selectedVideoSize == null) {
              // the auto value, default one
              selectedVideoSize =
                  new Dimension(
                      DeviceConfiguration.DEFAULT_VIDEO_WIDTH,
                      DeviceConfiguration.DEFAULT_VIDEO_HEIGHT);
            }
            deviceConfig.setVideoSize(selectedVideoSize);
          }
        });

    frameRateCheck.setSelected(
        deviceConfig.getFrameRate() != DeviceConfiguration.DEFAULT_VIDEO_FRAMERATE);
    frameRate.setEnabled(frameRateCheck.isSelected());

    if (frameRate.isEnabled()) frameRate.setValue(deviceConfig.getFrameRate());

    return centerAdvancedPanel;
  }
Beispiel #8
0
  /**
   * Creates basic controls for a type (AUDIO or VIDEO).
   *
   * @param type the type.
   * @return the build Component.
   */
  public static Component createBasicControls(final int type) {
    final JComboBox deviceComboBox = new JComboBox();

    deviceComboBox.setEditable(false);
    deviceComboBox.setModel(
        new DeviceConfigurationComboBoxModel(
            deviceComboBox, mediaService.getDeviceConfiguration(), type));

    JLabel deviceLabel = new JLabel(getLabelText(type));

    deviceLabel.setDisplayedMnemonic(getDisplayedMnemonic(type));
    deviceLabel.setLabelFor(deviceComboBox);

    final Container devicePanel = new TransparentPanel(new FlowLayout(FlowLayout.CENTER));

    devicePanel.setMaximumSize(new Dimension(WIDTH, 25));
    devicePanel.add(deviceLabel);
    devicePanel.add(deviceComboBox);

    final JPanel deviceAndPreviewPanel = new TransparentPanel(new BorderLayout());
    int preferredDeviceAndPreviewPanelHeight;

    switch (type) {
      case DeviceConfigurationComboBoxModel.AUDIO:
        preferredDeviceAndPreviewPanelHeight = 225;
        break;
      case DeviceConfigurationComboBoxModel.VIDEO:
        preferredDeviceAndPreviewPanelHeight = 305;
        break;
      default:
        preferredDeviceAndPreviewPanelHeight = 0;
        break;
    }
    if (preferredDeviceAndPreviewPanelHeight > 0)
      deviceAndPreviewPanel.setPreferredSize(
          new Dimension(WIDTH, preferredDeviceAndPreviewPanelHeight));
    deviceAndPreviewPanel.add(devicePanel, BorderLayout.NORTH);

    final ActionListener deviceComboBoxActionListener =
        new ActionListener() {
          public void actionPerformed(ActionEvent event) {
            boolean revalidateAndRepaint = false;

            for (int i = deviceAndPreviewPanel.getComponentCount() - 1; i >= 0; i--) {
              Component c = deviceAndPreviewPanel.getComponent(i);

              if (c != devicePanel) {
                deviceAndPreviewPanel.remove(i);
                revalidateAndRepaint = true;
              }
            }

            Component preview = null;

            if ((deviceComboBox.getSelectedItem() != null) && deviceComboBox.isShowing()) {
              preview =
                  createPreview(type, deviceComboBox, deviceAndPreviewPanel.getPreferredSize());
            }

            if (preview != null) {
              deviceAndPreviewPanel.add(preview, BorderLayout.CENTER);
              revalidateAndRepaint = true;
            }

            if (revalidateAndRepaint) {
              deviceAndPreviewPanel.revalidate();
              deviceAndPreviewPanel.repaint();
            }
          }
        };

    deviceComboBox.addActionListener(deviceComboBoxActionListener);
    /*
     * We have to initialize the controls to reflect the configuration
     * at the time of creating this instance. Additionally, because the
     * video preview will stop when it and its associated controls
     * become unnecessary, we have to restart it when the mentioned
     * controls become necessary again. We'll address the two goals
     * described by pretending there's a selection in the video combo
     * box when the combo box in question becomes displayable.
     */
    deviceComboBox.addHierarchyListener(
        new HierarchyListener() {
          public void hierarchyChanged(HierarchyEvent event) {
            if ((event.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
              SwingUtilities.invokeLater(
                  new Runnable() {
                    public void run() {
                      deviceComboBoxActionListener.actionPerformed(null);
                    }
                  });
            }
          }
        });

    return deviceAndPreviewPanel;
  }
Beispiel #9
0
  /**
   * Creates the UI controls which are to control the details of a specific <tt>AudioSystem</tt>.
   *
   * @param audioSystem the <tt>AudioSystem</tt> for which the UI controls to control its details
   *     are to be created
   * @param container the <tt>JComponent</tt> into which the UI controls which are to control the
   *     details of the specified <tt>audioSystem</tt> are to be added
   */
  public static void createAudioSystemControls(AudioSystem audioSystem, JComponent container) {
    GridBagConstraints constraints = new GridBagConstraints();

    constraints.anchor = GridBagConstraints.NORTHWEST;
    constraints.fill = GridBagConstraints.HORIZONTAL;
    constraints.weighty = 0;

    int audioSystemFeatures = audioSystem.getFeatures();
    boolean featureNotifyAndPlaybackDevices =
        ((audioSystemFeatures & AudioSystem.FEATURE_NOTIFY_AND_PLAYBACK_DEVICES) != 0);

    constraints.gridx = 0;
    constraints.insets = new Insets(3, 0, 3, 3);
    constraints.weightx = 0;

    constraints.gridy = 0;
    container.add(
        new JLabel(getLabelText(DeviceConfigurationComboBoxModel.AUDIO_CAPTURE)), constraints);
    if (featureNotifyAndPlaybackDevices) {
      constraints.gridy = 2;
      container.add(
          new JLabel(getLabelText(DeviceConfigurationComboBoxModel.AUDIO_PLAYBACK)), constraints);
      constraints.gridy = 3;
      container.add(
          new JLabel(getLabelText(DeviceConfigurationComboBoxModel.AUDIO_NOTIFY)), constraints);
    }

    constraints.gridx = 1;
    constraints.insets = new Insets(3, 3, 3, 0);
    constraints.weightx = 1;

    JComboBox captureCombo = null;

    if (featureNotifyAndPlaybackDevices) {
      captureCombo = new JComboBox();
      captureCombo.setEditable(false);
      captureCombo.setModel(
          new DeviceConfigurationComboBoxModel(
              captureCombo,
              mediaService.getDeviceConfiguration(),
              DeviceConfigurationComboBoxModel.AUDIO_CAPTURE));
      constraints.gridy = 0;
      container.add(captureCombo, constraints);
    }

    int anchor = constraints.anchor;
    SoundLevelIndicator capturePreview =
        new SoundLevelIndicator(
            SimpleAudioLevelListener.MIN_LEVEL, SimpleAudioLevelListener.MAX_LEVEL);

    constraints.anchor = GridBagConstraints.CENTER;
    constraints.gridy = (captureCombo == null) ? 0 : 1;
    container.add(capturePreview, constraints);
    constraints.anchor = anchor;

    constraints.gridy = GridBagConstraints.RELATIVE;

    if (featureNotifyAndPlaybackDevices) {
      JComboBox playbackCombo = new JComboBox();

      playbackCombo.setEditable(false);
      playbackCombo.setModel(
          new DeviceConfigurationComboBoxModel(
              captureCombo,
              mediaService.getDeviceConfiguration(),
              DeviceConfigurationComboBoxModel.AUDIO_PLAYBACK));
      container.add(playbackCombo, constraints);

      JComboBox notifyCombo = new JComboBox();

      notifyCombo.setEditable(false);
      notifyCombo.setModel(
          new DeviceConfigurationComboBoxModel(
              captureCombo,
              mediaService.getDeviceConfiguration(),
              DeviceConfigurationComboBoxModel.AUDIO_NOTIFY));
      container.add(notifyCombo, constraints);
    }

    if ((AudioSystem.FEATURE_ECHO_CANCELLATION & audioSystemFeatures) != 0) {
      final SIPCommCheckBox echoCancelCheckBox =
          new SIPCommCheckBox(
              NeomediaActivator.getResources().getI18NString("impl.media.configform.ECHOCANCEL"));

      /*
       * First set the selected one, then add the listener in order to
       * avoid saving the value when using the default one and only
       * showing to user without modification.
       */
      echoCancelCheckBox.setSelected(mediaService.getDeviceConfiguration().isEchoCancel());
      echoCancelCheckBox.addItemListener(
          new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
              mediaService.getDeviceConfiguration().setEchoCancel(echoCancelCheckBox.isSelected());
            }
          });
      container.add(echoCancelCheckBox, constraints);
    }

    if ((AudioSystem.FEATURE_DENOISE & audioSystemFeatures) != 0) {
      final SIPCommCheckBox denoiseCheckBox =
          new SIPCommCheckBox(
              NeomediaActivator.getResources().getI18NString("impl.media.configform.DENOISE"));

      /*
       * First set the selected one, then add the listener in order to
       * avoid saving the value when using the default one and only
       * showing to user without modification.
       */
      denoiseCheckBox.setSelected(mediaService.getDeviceConfiguration().isDenoise());
      denoiseCheckBox.addItemListener(
          new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
              mediaService.getDeviceConfiguration().setDenoise(denoiseCheckBox.isSelected());
            }
          });
      container.add(denoiseCheckBox, constraints);
    }

    createAudioPreview(audioSystem, captureCombo, capturePreview);
  }
  /**
   * Create preview component.
   *
   * @param comboBox the options.
   * @return the component.
   */
  private static Component createPreview(final JComboBox comboBox) {
    final JComponent preview;

    JLabel noPreview =
        new JLabel(GuiActivator.getResources().getI18NString("impl.media.configform.NO_PREVIEW"));
    noPreview.setHorizontalAlignment(SwingConstants.CENTER);
    noPreview.setVerticalAlignment(SwingConstants.CENTER);

    preview = createVideoContainer(noPreview);

    preview.setPreferredSize(new Dimension(WIDTH, 280));
    preview.setMaximumSize(new Dimension(WIDTH, 280));

    final ActionListener comboBoxListener =
        new ActionListener() {
          public void actionPerformed(ActionEvent event) {
            MediaDevice device = (MediaDevice) comboBox.getSelectedItem();

            if ((device != null) && device.equals(videoDeviceInPreview)) return;

            Exception exception;
            try {
              createPreview(device, preview);
              exception = null;
            } catch (IOException ex) {
              exception = ex;
            } catch (MediaException ex) {
              exception = ex;
            }
            if (exception != null) {
              logger.error("Failed to create preview for device " + device, exception);

              device = null;
            }

            videoDeviceInPreview = device;
          }
        };
    comboBox.addActionListener(comboBoxListener);

    /*
     * We have to initialize the controls to reflect the configuration
     * at the time of creating this instance. Additionally, because the
     * video preview will stop when it and its associated controls
     * become unnecessary, we have to restart it when the mentioned
     * controls become necessary again. We'll address the two goals
     * described by pretending there's a selection in the video combo
     * box when the combo box in question becomes displayable.
     */
    comboBox.addHierarchyListener(
        new HierarchyListener() {
          public void hierarchyChanged(HierarchyEvent event) {
            if (((event.getChangeFlags() & HierarchyEvent.DISPLAYABILITY_CHANGED) != 0)
                && comboBox.isDisplayable()) {
              // let current changes end their execution
              // and after that trigger action on combobox
              SwingUtilities.invokeLater(
                  new Runnable() {
                    public void run() {
                      comboBoxListener.actionPerformed(null);
                    }
                  });
            } else {
              if (!comboBox.isDisplayable()) videoDeviceInPreview = null;
            }
          }
        });

    return preview;
  }