Java tutorial
/** * Copyright (c) 2013, 2014 Denis Nikiforov. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Denis Nikiforov - initial API and implementation */ package org.emftext.language.xpath2.resource.xpath2.ui; import java.io.IOException; import java.io.StringReader; import java.util.Iterator; import org.eclipse.core.runtime.Assert; import org.eclipse.core.runtime.ListenerList; import org.eclipse.jface.action.ToolBarManager; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.jface.text.AbstractInformationControl; import org.eclipse.jface.text.IDelayedInputChangeProvider; import org.eclipse.jface.text.IInformationControlExtension2; import org.eclipse.jface.text.IInputChangedListener; import org.eclipse.jface.text.TextPresentation; import org.eclipse.swt.SWT; import org.eclipse.swt.SWTError; import org.eclipse.swt.browser.Browser; import org.eclipse.swt.browser.LocationListener; import org.eclipse.swt.browser.OpenWindowListener; import org.eclipse.swt.browser.ProgressAdapter; import org.eclipse.swt.browser.ProgressEvent; import org.eclipse.swt.browser.WindowEvent; import org.eclipse.swt.custom.StyleRange; import org.eclipse.swt.events.KeyEvent; import org.eclipse.swt.events.KeyListener; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.graphics.TextLayout; import org.eclipse.swt.graphics.TextStyle; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Menu; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.Slider; /** * Displays HTML information in a {@link Browser} widget. * <p> * This IInformationControlExtension2 expects {@link #setInput(Object)} to be * called with an argument of type BrowserInformationControlInput. * </p> * <p>Moved into this package from * <code>org.eclipse.jface.internal.text.revisions</code>.</p> * <p>This class may be instantiated; it is not intended to be subclassed.</p> * <p>Current problems: * <ul> * <li>the size computation is too small</li> * <li>focusLost event is not sent - see * https://bugs.eclipse.org/bugs/show_bug.cgi?id=84532</li> * </ul> * </p> * * @since 3.2 */ public class Xpath2BrowserInformationControl extends AbstractInformationControl implements IInformationControlExtension2, IDelayedInputChangeProvider { /** * Tells whether the SWT Browser widget and hence this information control is * available. * * @param parent the parent component used for checking or <code>null</code> if * none * * @return <code>true</code> if this control is available */ public static boolean isAvailable(Composite parent) { if (!fgAvailabilityChecked) { try { Browser browser = new Browser(parent, SWT.NONE); browser.dispose(); fgIsAvailable = true; Slider sliderV = new Slider(parent, SWT.VERTICAL); Slider sliderH = new Slider(parent, SWT.HORIZONTAL); int width = sliderV.computeSize(SWT.DEFAULT, SWT.DEFAULT).x; int height = sliderH.computeSize(SWT.DEFAULT, SWT.DEFAULT).y; fgScrollBarSize = new Point(width, height); sliderV.dispose(); sliderH.dispose(); } catch (SWTError er) { fgIsAvailable = false; } finally { fgAvailabilityChecked = true; } } return fgIsAvailable; } /** * Minimal size constraints. */ private static final int MIN_WIDTH = 80; private static final int MIN_HEIGHT = 50; /** * Availability checking cache. */ private static boolean fgIsAvailable = false; private static boolean fgAvailabilityChecked = false; /** * Cached scroll bar width and height */ private static Point fgScrollBarSize; /** * The control's browser widget */ private Browser fBrowser; /** * Tells whether the browser has content */ private boolean fBrowserHasContent; /** * Text layout used to approximate size of content when rendered in browser */ private TextLayout fTextLayout; /** * Bold text style */ private TextStyle fBoldStyle; private org.emftext.language.xpath2.resource.xpath2.ui.Xpath2DocBrowserInformationControlInput fInput; /** * <code>true</code> iff the browser has completed loading of the last input set * via {@link #setInformation(String)}. */ private boolean fCompleted = false; /** * The listener to be notified when a delayed location changing event happened. */ private IInputChangedListener fDelayedInputChangeListener; /** * The listeners to be notified when the input changed. */ private ListenerList fInputChangeListeners = new ListenerList(ListenerList.IDENTITY); /** * The symbolic name of the font used for size computations, or <code>null</code> * to use dialog font. */ private final String fSymbolicFontName; /** * Creates a browser information control with the given shell as parent. * * @param parent the parent shell * @param symbolicFontName the symbolic name of the font used for size computations * @param resizable <code>true</code> if the control should be resizable */ public Xpath2BrowserInformationControl(Shell parent, String symbolicFontName, boolean resizable) { super(parent, resizable); fSymbolicFontName = symbolicFontName; create(); } /** * Creates a browser information control with the given shell as parent. * * @param parent the parent shell * @param symbolicFontName the symbolic name of the font used for size computations * @param statusFieldText the text to be used in the optional status field or * <code>null</code> if the status field should be hidden */ public Xpath2BrowserInformationControl(Shell parent, String symbolicFontName, String statusFieldText) { super(parent, statusFieldText); fSymbolicFontName = symbolicFontName; create(); } /** * Creates a browser information control with the given shell as parent. * * @param parent the parent shell * @param symbolicFontName the symbolic name of the font used for size computations * @param toolBarManager the manager or <code>null</code> if toolbar is not desired * * @since 3.4 */ public Xpath2BrowserInformationControl(Shell parent, String symbolicFontName, ToolBarManager toolBarManager) { super(parent, toolBarManager); fSymbolicFontName = symbolicFontName; create(); } /** * * @see org.eclipse.jface.text.AbstractInformationControl#createContent(Composite) */ protected void createContent(Composite parent) { fBrowser = new Browser(parent, SWT.NONE); Display display = getShell().getDisplay(); fBrowser.setForeground(display.getSystemColor(SWT.COLOR_INFO_FOREGROUND)); fBrowser.setBackground(display.getSystemColor(SWT.COLOR_INFO_BACKGROUND)); fBrowser.addKeyListener(new KeyListener() { public void keyPressed(KeyEvent e) { if (e.character == 0x1B) // ESC dispose(); // XXX: Just hide? Would avoid constant recreations. } public void keyReleased(KeyEvent e) { } }); fBrowser.addProgressListener(new ProgressAdapter() { public void completed(ProgressEvent event) { fCompleted = true; } }); fBrowser.addOpenWindowListener(new OpenWindowListener() { public void open(WindowEvent event) { event.required = true; // Cancel opening of new windows } }); // Replace browser's built-in context menu with none fBrowser.setMenu(new Menu(getShell(), SWT.NONE)); createTextLayout(); } /** * {@inheritDoc} This control can handle {@link String}(no handle) and */ public void setInput(Object input) { Assert.isLegal(input == null || input instanceof String || input instanceof org.emftext.language.xpath2.resource.xpath2.ui.Xpath2DocBrowserInformationControlInput); if (input instanceof String) { setInformation((String) input); return; } fInput = (org.emftext.language.xpath2.resource.xpath2.ui.Xpath2DocBrowserInformationControlInput) input; String content = null; if (fInput != null) content = fInput.getHtml(); fBrowserHasContent = content != null && content.length() > 0; if (!fBrowserHasContent) content = "<html><body ></html>"; boolean RTL = (getShell().getStyle() & SWT.RIGHT_TO_LEFT) != 0; boolean resizable = isResizable(); // The default "overflow:auto" would not result in a predictable width for the // client area and the re-wrapping would cause visual noise String[] styles = null; if (RTL && resizable) { styles = new String[] { "direction:rtl;", "overflow:scroll;", "word-wrap:break-word;" }; } else if (RTL && !resizable) { styles = new String[] { "direction:rtl;", "overflow:hidden;", "word-wrap:break-word;" }; } else if (!resizable) { // XXX: In IE, "word-wrap: break-word;" causes bogus wrapping even in non-broken // words :-(see e.g. Javadoc of String). Re-check whether we really still need // this now that the Javadoc Hover header already sets this style. styles = new String[] { "overflow:hidden;"/*, "word-wrap: break-word;"*/ }; } else { styles = new String[] { "overflow:scroll;" }; } StringBuffer buffer = new StringBuffer(content); org.emftext.language.xpath2.resource.xpath2.ui.Xpath2HTMLPrinter.insertStyles(buffer, styles); content = buffer.toString(); // XXX: Should add some JavaScript here that shows something like "(continued...)" // or "..." at the end of the visible area when the page overflowed with // "overflow:hidden;". fCompleted = false; fBrowser.setText(content); Object[] listeners = fInputChangeListeners.getListeners(); for (int i = 0; i < listeners.length; i++) { ((IInputChangedListener) listeners[i]).inputChanged(fInput); } } public void setVisible(boolean visible) { Shell shell = getShell(); if (shell.isVisible() == visible) { return; } if (!visible) { super.setVisible(false); setInput(null); return; } // The Browser widget flickers when made visible while it is not completely // loaded. The fix is to delay the call to setVisible until either loading is // completed (see ProgressListener in constructor), or a timeout has been reached. final Display display = shell.getDisplay(); // Make sure the display wakes from sleep after timeout: display.timerExec(100, new Runnable() { public void run() { fCompleted = true; } }); while (!fCompleted) { // Drive the event loop to process the events required to load the browser // widget's contents: if (!display.readAndDispatch()) { display.sleep(); } } shell = getShell(); if (shell == null || shell.isDisposed()) { return; } // Avoids flickering when replacing hovers, especially on Vista in ON_CLICK mode. // Causes flickering on GTK. Carbon does not care. if ("win32".equals(SWT.getPlatform())) { shell.moveAbove(null); } super.setVisible(true); } /** * * @see AbstractInformationControl#setSize(int, int) */ public void setSize(int width, int height) { fBrowser.setRedraw(false); // avoid flickering try { super.setSize(width, height); } finally { fBrowser.setRedraw(true); } } /** * Creates and initializes the text layout used to compute the size hint. * * @since 3.2 */ private void createTextLayout() { fTextLayout = new TextLayout(fBrowser.getDisplay()); // Initialize fonts String symbolicFontName = fSymbolicFontName == null ? JFaceResources.DIALOG_FONT : fSymbolicFontName; Font font = JFaceResources.getFont(symbolicFontName); fTextLayout.setFont(font); fTextLayout.setWidth(-1); font = JFaceResources.getFontRegistry().getBold(symbolicFontName); fBoldStyle = new TextStyle(font, null, null); // Compute and set tab width fTextLayout.setText(" "); int tabWidth = fTextLayout.getBounds().width; fTextLayout.setTabs(new int[] { tabWidth }); fTextLayout.setText(""); } public void dispose() { if (fTextLayout != null) { fTextLayout.dispose(); fTextLayout = null; } fBrowser = null; super.dispose(); } public Point computeSizeHint() { Point sizeConstraints = getSizeConstraints(); Rectangle trim = computeTrim(); int height = trim.height; TextPresentation presentation = new TextPresentation(); String text; try { text = org.emftext.language.xpath2.resource.xpath2.ui.Xpath2HTMLPrinter .html2text(new StringReader(fInput.getHtml()), presentation); } catch (IOException e) { text = ""; } fTextLayout.setText(text); fTextLayout.setWidth(sizeConstraints == null ? SWT.DEFAULT : sizeConstraints.x - trim.width); Iterator<?> iter = presentation.getAllStyleRangeIterator(); while (iter.hasNext()) { StyleRange sr = (StyleRange) iter.next(); if (sr.fontStyle == SWT.BOLD) { fTextLayout.setStyle(fBoldStyle, sr.start, sr.start + sr.length - 1); } } Rectangle bounds = fTextLayout.getBounds(); // does not return minimum width, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=217446 int lineCount = fTextLayout.getLineCount(); int textWidth = 0; for (int i = 0; i < lineCount; i++) { Rectangle rect = fTextLayout.getLineBounds(i); int lineWidth = rect.x + rect.width; if (i == 0) { lineWidth += fInput.getLeadingImageWidth(); } textWidth = Math.max(textWidth, lineWidth); } bounds.width = textWidth; fTextLayout.setText(""); int minWidth = bounds.width; height = height + bounds.height; // Add some air to accommodate for different browser renderings minWidth += 15; height += 15; // Apply max size constraints if (sizeConstraints != null) { if (sizeConstraints.x != SWT.DEFAULT) { minWidth = Math.min(sizeConstraints.x, minWidth + trim.width); } if (sizeConstraints.y != SWT.DEFAULT) { height = Math.min(sizeConstraints.y, height); } } // Ensure minimal size int width = Math.max(MIN_WIDTH, minWidth); height = Math.max(MIN_HEIGHT, height); Point windowSize = new Point(width, height); return windowSize; } /** * * @see org.eclipse.jface.text.IInformationControlExtension3#computeTrim() */ public Rectangle computeTrim() { Rectangle trim = super.computeTrim(); if (isResizable()) { boolean RTL = (getShell().getStyle() & SWT.RIGHT_TO_LEFT) != 0; if (RTL) { trim.x -= fgScrollBarSize.x; } trim.width += fgScrollBarSize.x; trim.height += fgScrollBarSize.y; } return trim; } /** * Adds the listener to the collection of listeners who will be notified when the * current location has changed or is about to change. * * @param listener the location listener * * @since 3.4 */ public void addLocationListener(LocationListener listener) { fBrowser.addLocationListener(listener); } public void setForegroundColor(Color foreground) { super.setForegroundColor(foreground); fBrowser.setForeground(foreground); } public void setBackgroundColor(Color background) { super.setBackgroundColor(background); fBrowser.setBackground(background); } public boolean hasContents() { return fBrowserHasContent; } /** * Adds a listener for input changes to this input change provider. Has no effect * if an identical listener is already registered. * * @param inputChangeListener the listener to add * * @since 3.4 */ public void addInputChangeListener(IInputChangedListener inputChangeListener) { Assert.isNotNull(inputChangeListener); fInputChangeListeners.add(inputChangeListener); } /** * Removes the given input change listener from this input change provider. Has no * effect if an identical listener is not registered. * * @param inputChangeListener the listener to remove * * @since 3.4 */ public void removeInputChangeListener(IInputChangedListener inputChangeListener) { fInputChangeListeners.remove(inputChangeListener); } /** * * @see * IDelayedInputChangeProvider#setDelayedInputChangeListener(IInputChangedListener) * * @since 3.4 */ public void setDelayedInputChangeListener(IInputChangedListener inputChangeListener) { fDelayedInputChangeListener = inputChangeListener; } /** * Tells whether a delayed input change listener is registered. * * @return <code>true</code> iff a delayed input change listener is currently * registered * * @since 3.4 */ public boolean hasDelayedInputChangeListener() { return fDelayedInputChangeListener != null; } /** * Notifies listeners of a delayed input change. * * @param newInput the new input, or <code>null</code> to request cancellation * * @since 3.4 */ public void notifyDelayedInputChange(Object newInput) { if (fDelayedInputChangeListener != null) fDelayedInputChangeListener.inputChanged(newInput); } /** * * @see java.lang.Object#toString() * * @since 3.4 */ public String toString() { String style = (getShell().getStyle() & SWT.RESIZE) == 0 ? "fixed" : "resizeable"; return super.toString() + " - style: " + style; } /** * * @return the current browser input or <code>null</code> */ public org.emftext.language.xpath2.resource.xpath2.ui.Xpath2DocBrowserInformationControlInput getInput() { return fInput; } /** * * @see * org.eclipse.jface.text.IInformationControlExtension5#computeSizeConstraints(int, * int) */ public Point computeSizeConstraints(int widthInChars, int heightInChars) { if (fSymbolicFontName == null) { return null; } GC gc = new GC(fBrowser); Font font = fSymbolicFontName == null ? JFaceResources.getDialogFont() : JFaceResources.getFont(fSymbolicFontName); gc.setFont(font); int width = gc.getFontMetrics().getAverageCharWidth(); int height = gc.getFontMetrics().getHeight(); gc.dispose(); return new Point(widthInChars * width, heightInChars * height); } }