Java tutorial
/*- * Copyright 2010 Diamond Light Source Ltd. * * This file is part of GDA. * * GDA is free software: you can redistribute it and/or modify it under the * terms of the GNU General Public License version 3 as published by the Free * Software Foundation. * * GDA 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 GDA. If not, see <http://www.gnu.org/licenses/>. */ package uk.ac.gda.ui.status; import org.eclipse.core.runtime.Assert; import org.eclipse.jface.action.ContributionItem; import org.eclipse.jface.action.IContributionManager; import org.eclipse.jface.action.StatusLineLayoutData; import org.eclipse.jface.util.Util; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.CLabel; import org.eclipse.swt.events.MouseListener; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.FontMetrics; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Label; /** * A contribution item to be used with status line managers. * <p> * This class may be instantiated; it is not intended to be subclassed. * </p> * * @since 3.4 */ public class LinkContributionItem extends ContributionItem { private final static int DEFAULT_CHAR_WIDTH = 40; private int charWidth; private CLabel link; /** * The composite into which this contribution item has been placed. This * will be <code>null</code> if this instance has not yet been * initialized. */ private Composite statusLine = null; private String text = Util.ZERO_LENGTH_STRING; private int widthHint = -1; private int heightHint = -1; private MouseListener mouseListener; private Image image; private String tooltip; /** * Creates a status line contribution item with the given id. * * @param id * the contribution item's id, or <code>null</code> if it is to * have no id */ public LinkContributionItem(String id) { this(id, DEFAULT_CHAR_WIDTH); } /** * Creates a status line contribution item with the given id that displays * the given number of characters. * * @param id * the contribution item's id, or <code>null</code> if it is to * have no id * @param charWidth * the number of characters to display */ public LinkContributionItem(String id, int charWidth) { super(id); this.charWidth = charWidth; setVisible(false); // no text to start with } @Override public void fill(Composite parent) { statusLine = parent; Label sep = new Label(parent, SWT.SEPARATOR); link = new CLabel(statusLine, SWT.SHADOW_NONE); if (mouseListener != null) { link.addMouseListener(mouseListener); } if (image != null) { link.setImage(image); } if (tooltip != null) { link.setToolTipText(tooltip); } if (widthHint < 0) { GC gc = new GC(statusLine); gc.setFont(statusLine.getFont()); FontMetrics fm = gc.getFontMetrics(); widthHint = fm.getAverageCharWidth() * charWidth; heightHint = fm.getHeight(); gc.dispose(); } StatusLineLayoutData data = new StatusLineLayoutData(); data.widthHint = widthHint; link.setLayoutData(data); link.setText(text); data = new StatusLineLayoutData(); data.heightHint = heightHint; sep.setLayoutData(data); } /** * An accessor for the current location of this status line contribution * item -- relative to the display. * * @return The current location of this status line; <code>null</code> if * not yet initialized. */ public Point getDisplayLocation() { if ((link != null) && (statusLine != null)) { return statusLine.toDisplay(link.getLocation()); } return null; } /** * Retrieves the text that is being displayed in the status line. * * @return the text that is currently being displayed */ public String getText() { return text; } /** * Sets the text to be displayed in the status line. * * @param text * the text to be displayed, must not be <code>null</code> */ public void setText(String text) { Assert.isNotNull(text); this.text = escape(text); if (link != null && !link.isDisposed()) { link.setText(this.text); } updateManager(); } public void setBackground(Color background) { link.setBackground(background); } private void updateManager() { if (this.text.length() == 0) { if (isVisible()) { setVisible(false); IContributionManager contributionManager = getParent(); if (contributionManager != null) { contributionManager.update(true); } } } else { if (!isVisible()) { setVisible(true); IContributionManager contributionManager = getParent(); if (contributionManager != null) { contributionManager.update(true); } } } } private String escape(String text) { return Util.replaceAll(text, "&", "&&"); //$NON-NLS-1$//$NON-NLS-2$ } /** * @param txt */ public void setToolTipText(String txt) { Assert.isNotNull(text); tooltip = escape(txt); if (link != null && !link.isDisposed()) { link.setToolTipText(txt); } updateManager(); } /** * @param image */ public void setImage(Image image) { this.image = image; if (link != null && !link.isDisposed()) { this.link.setImage(image); } updateManager(); } /** * @param l */ public void addMouseListener(MouseListener l) { if (link != null) { this.link.addMouseListener(l); this.mouseListener = null; } else { this.mouseListener = l; } } }