Java tutorial
package org.marketcetera.photon.notification; import java.text.CharacterIterator; import java.text.StringCharacterIterator; import org.eclipse.core.runtime.Assert; import org.eclipse.core.runtime.AssertionFailedException; import org.eclipse.jface.layout.GridDataFactory; import org.eclipse.jface.layout.GridLayoutFactory; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotificationPopup; import org.eclipse.swt.SWT; import org.eclipse.swt.events.PaintEvent; import org.eclipse.swt.events.PaintListener; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Label; import org.marketcetera.core.notifications.INotification; import org.marketcetera.core.notifications.INotification.Severity; import org.marketcetera.util.misc.ClassVersion; /* $License$ */ /** * A popup that displays an {@link INotification}. * * This class may be subclassed to override * <ul> * <li>{@link #getImage(INotification)} - the images displayed for the * notifications</li> * <li>{@link #getLabelFont()} - the font used for the heading labels</li> * <li>{@link #fitLineToWidth(GC, String, int)} - the algorithm for truncating * the subject text to fit on a single line</li> * </ul> * * @author <a href="mailto:will@marketcetera.com">Will Horn</a> * @version $Id$ * @since 0.8.0 */ @ClassVersion("$Id$") //$NON-NLS-1$ @SuppressWarnings("restriction") public class DesktopNotificationPopup extends AbstractNotificationPopup { /** * time in milliseconds before the popup closes automatically */ private static final int CLOSE_DELAY = 4000; /** * used for truncating long text */ private static final String ELLIPSIS = Messages.POPUP_ELLIPSIS.getText(); /** * the notification */ private final INotification mNotification; /** * Constructor. * * Subclasses should call this constructor, but may customize/override * configuration by calling {@link #setFadingEnabled(boolean)} and * {@link #setDelayClose(long)}. * * @param display * the display used by {@link AbstractNotificationPopup} * @param notification * the notification to display, cannot be null * @throws AssertionFailedException * if notification is null */ public DesktopNotificationPopup(Display display, INotification notification) { super(display); Assert.isNotNull(notification); this.mNotification = notification; setFadingEnabled(true); setDelayClose(CLOSE_DELAY); } @Override protected final void createContentArea(Composite parent) { createHeading(parent); createLabel(parent, mNotification.getBody(), parent.getFont(), SWT.WRAP); } /** * Creates the heading area of the popup. * * @param parent * the parent */ private void createHeading(Composite parent) { Composite composite = new Composite(parent, SWT.NO_FOCUS); composite.setBackground(parent.getBackground()); GridDataFactory.fillDefaults().grab(true, true).applyTo(composite); // layout depends on whether there is an image Image image = getImage(mNotification); GridLayoutFactory layout = GridLayoutFactory.swtDefaults().spacing(15, 5); if (image != null) { layout.numColumns(3).applyTo(composite); Label imageLabel = new Label(composite, SWT.NO_FOCUS); imageLabel.setBackground(parent.getBackground()); GridDataFactory.defaultsFor(imageLabel).span(1, 3).applyTo(imageLabel); imageLabel.setImage(image); } else { layout.numColumns(2).applyTo(composite); } createLabel(composite, Messages.POPUP_SUBJECT_LABEL.getText(), getLabelFont(), SWT.RIGHT); // Special label that truncates text with "..." as necessary final Label subject = new Label(composite, SWT.NO_FOCUS); subject.setBackground(parent.getBackground()); subject.setFont(parent.getFont()); GridDataFactory.fillDefaults().grab(true, false).applyTo(subject); subject.addPaintListener(new PaintListener() { @Override public void paintControl(PaintEvent e) { subject.setText(fitLineToWidth(e.gc, mNotification.getSubject(), e.width)); // The text only needs to be calculated once. subject.removePaintListener(this); } }); createLabel(composite, Messages.POPUP_PRIORITY_LABEL.getText(), getLabelFont(), SWT.RIGHT); createLabel(composite, getSeverityLabel(mNotification.getSeverity()), parent.getFont(), SWT.NONE); createLabel(composite, Messages.POPUP_TIMESTAMP_LABEL.getText(), getLabelFont(), SWT.RIGHT); createLabel(composite, mNotification.getDate().toString(), parent.getFont(), SWT.NONE); } /** * Helper method to create a label. * * @param parent * the parent composite * @param text * the label text * @param font * the label font * @param style * the label style * @return a label configured with the provided parameters */ private Label createLabel(Composite parent, String text, Font font, int style) { Label label = new Label(parent, SWT.NO_FOCUS | style); label.setBackground(parent.getBackground()); label.setFont(font); GridDataFactory.defaultsFor(label).applyTo(label); label.setText(text); return label; } /** * Helper method to provide label text for a given {@link Severity}. * * @param severity * the severity * @return label for the severity */ private String getSeverityLabel(Severity severity) { switch (severity) { case HIGH: return Messages.POPUP_SEVERITY_LABEL_HIGH.getText(); case MEDIUM: return Messages.POPUP_SEVERITY_LABEL_MEDIUM.getText(); case LOW: return Messages.POPUP_SEVERITY_LABEL_LOW.getText(); default: return ""; //$NON-NLS-1$ } } /** * Provides the label font. Default is to the bold version of the JFace * default font. * * Subclasses can override to provide a different font. * * @return the font to use for heading labels */ protected Font getLabelFont() { return JFaceResources.getFontRegistry().getBold(JFaceResources.DEFAULT_FONT); } /** * Provides the image to use for the given notification. Default is based on * severity: * <ul> * <li>HIGH - SWT.ICON_ERROR</li> * <li>MEDIUM - SWT.ICON_WARNING</li> * <li>LOW - SWT.ICON_INFORMATION</li> * </ul> * * Subclass can return null if no image is desired. * * @return the image to display or null for no image */ protected Image getImage(INotification notification) { switch (notification.getSeverity()) { case HIGH: return getSWTImage(SWT.ICON_ERROR); case MEDIUM: return getSWTImage(SWT.ICON_WARNING); default: return getSWTImage(SWT.ICON_INFORMATION); } } /** * Strategy for truncating text to a specified width using ellipsis. The * default strategy tries to break at a space if possible. * * Subclass implementations must return a String that fits inside the given * width when rendered using the provided GC. * * @param gc * the graphics context * @param text * the text to fit * @param width * the maximum width * @return a new string, shortened with ellipsis if necessary */ protected String fitLineToWidth(GC gc, String text, int width) { int pixels = 0; int dotextent = gc.stringExtent(ELLIPSIS).x; if (dotextent >= width) { // No point truncating if the ellipsis is greater than the provided // width return ""; //$NON-NLS-1$ } StringCharacterIterator iter = new StringCharacterIterator(text); pixels += gc.getAdvanceWidth(iter.current()); char c; while ((c = iter.next()) != CharacterIterator.DONE) { pixels += gc.getAdvanceWidth(c); if (pixels > width) { pixels += dotextent; while ((pixels -= gc.getAdvanceWidth(c)) > width) c = iter.previous(); int index = iter.getIndex(); while (c != ' ' && c != CharacterIterator.DONE) c = iter.previous(); if (c != CharacterIterator.DONE) index = iter.getIndex(); return text.substring(0, index) + ELLIPSIS; } } return text; } /** * Helper method to get an <code>Image</code> from the provided SWT image * constant. * * @param imageID * the SWT image constant * @return image the image */ private Image getSWTImage(final int imageID) { return getShell().getDisplay().getSystemImage(imageID); } @Override public final int open() { // Simply call the superclass implementation. This method was overridden // purely to hide the discouraged access warning from clients. return super.open(); } }