Java tutorial
/******************************************************************************* * Copyright (c) 2003, 2011 IBM Corporation and others. * 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: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.e4.ui.internal.progress; import org.eclipse.core.runtime.QualifiedName; import org.eclipse.core.runtime.jobs.Job; import org.eclipse.e4.ui.model.application.MApplication; import org.eclipse.e4.ui.model.application.ui.basic.MWindow; import org.eclipse.e4.ui.progress.IProgressConstants; import org.eclipse.jface.viewers.Viewer; import org.eclipse.jface.viewers.ViewerComparator; import org.eclipse.jface.window.IShellProvider; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; /** * The ProgressUtil is a class that contains static utility methods used for the * progress API. */ public class ProgressManagerUtil { /** * A constant used by the progress support to determine if an operation is * too short to show progress. */ public static final long SHORT_OPERATION_TIME = 250; static final QualifiedName KEEP_PROPERTY = IProgressConstants.KEEP_PROPERTY; static final QualifiedName KEEPONE_PROPERTY = IProgressConstants.KEEPONE_PROPERTY; static final Object[] EMPTY_OBJECT_ARRAY = new Object[0]; private static String ellipsis = ProgressMessages.ProgressFloatingWindow_EllipsisValue; static final QualifiedName INFRASTRUCTURE_PROPERTY = new QualifiedName("org.eclipse.e4.ui", //$NON-NLS-1$ "INFRASTRUCTURE_PROPERTY"); static MApplication application = null; static void setApplication(MApplication application) { ProgressManagerUtil.application = application; } /** * Return a viewer comparator for looking at the jobs. * * @return ViewerComparator */ static ViewerComparator getProgressViewerComparator() { return new ViewerComparator() { @SuppressWarnings({ "unchecked", "rawtypes" }) @Override public int compare(Viewer testViewer, Object e1, Object e2) { return ((Comparable) e1).compareTo(e2); } }; } /** * Shorten the given text <code>t</code> so that its length doesn't exceed * the given width. The default implementation replaces characters in the * center of the original string with an ellipsis ("..."). Override if you * need a different strategy. * * @param textValue * @param control * @return String */ static String shortenText(String textValue, Control control) { if (textValue == null) { return null; } GC gc = new GC(control); int maxWidth = control.getBounds().width - 5; int maxExtent = gc.textExtent(textValue).x; if (maxExtent < maxWidth) { gc.dispose(); return textValue; } int length = textValue.length(); int charsToClip = Math.round(0.95f * length * (1 - ((float) maxWidth / maxExtent))); int secondWord = findSecondWhitespace(textValue, gc, maxWidth); int pivot = ((length - secondWord) / 2) + secondWord; int start = pivot - (charsToClip / 2); int end = pivot + (charsToClip / 2) + 1; while (start >= 0 && end < length) { String s1 = textValue.substring(0, start); String s2 = textValue.substring(end, length); String s = s1 + ellipsis + s2; int l = gc.textExtent(s).x; if (l < maxWidth) { gc.dispose(); return s; } start--; end++; } gc.dispose(); return textValue; } /** * Find the second index of a whitespace. Return the first index if there * isn't one or 0 if there is no space at all. * * @param textValue * @param gc * The GC to test max length * @param maxWidth * The maximim extent * @return int */ private static int findSecondWhitespace(String textValue, GC gc, int maxWidth) { int firstCharacter = 0; char[] chars = textValue.toCharArray(); // Find the first whitespace for (int i = 0; i < chars.length; i++) { if (Character.isWhitespace(chars[i])) { firstCharacter = i; break; } } // If we didn't find it once don't continue if (firstCharacter == 0) { return 0; } // Initialize to firstCharacter in case there is no more whitespace int secondCharacter = firstCharacter; // Find the second whitespace for (int i = firstCharacter; i < chars.length; i++) { if (Character.isWhitespace(chars[i])) { secondCharacter = i; break; } } // Check that we haven't gone over max width. Throw // out an index that is too high if (gc.textExtent(textValue.substring(0, secondCharacter)).x > maxWidth) { if (gc.textExtent(textValue.substring(0, firstCharacter)).x > maxWidth) { return 0; } return firstCharacter; } return secondCharacter; } /** * If there are any modal shells open reschedule openJob to wait until they * are closed. Return true if it rescheduled, false if there is nothing * blocking it. * * @param openJob * @return boolean. true if the job was rescheduled due to modal dialogs. */ public static boolean rescheduleIfModalShellOpen(Job openJob) { Shell modal = getModalShellExcluding(null); if (modal == null) { return false; } // try again in a few seconds openJob.schedule(10); return true; } /** * Return whether or not it is safe to open this dialog. If so then return * <code>true</code>. If not then set it to open itself when it has had * ProgressManager#longOperationTime worth of ticks. * * @param dialog * ProgressMonitorJobsDialog that will be opening * @param excludedShell * The shell * @return boolean. <code>true</code> if it can open. Otherwise return * false and set the dialog to tick. */ public static boolean safeToOpen(ProgressMonitorJobsDialog dialog, Shell excludedShell) { Shell modal = getModalShellExcluding(excludedShell); if (modal == null) { return true; } dialog.watchTicks(); return false; } /** * Return the modal shell that is currently open. If there isn't one then * return null. If there are stacked modal shells, return the top one. * * @param shell * A shell to exclude from the search. May be <code>null</code>. * * @return Shell or <code>null</code>. */ public static Shell getModalShellExcluding(Shell shell) { // If shell is null or disposed, then look through all shells if (shell == null || shell.isDisposed()) { return getModalChildExcluding(Display.getCurrent().getShells(), shell); } // Start with the shell to exclude and check it's shells return getModalChildExcluding(shell.getShells(), shell); } /** * Return the modal shell that is currently open. If there isn't one then * return null. * * @param toSearch shells to search for modal children * @param toExclude shell to ignore * @return the most specific modal child, or null if none */ private static Shell getModalChildExcluding(Shell[] toSearch, Shell toExclude) { int modal = SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL | SWT.PRIMARY_MODAL; // Make sure we don't pick a parent that has a modal child (this can // lock the app) // If we picked a parent with a modal child, use the modal child instead for (int i = toSearch.length - 1; i >= 0; i--) { Shell shell = toSearch[i]; if (shell.equals(toExclude)) { continue; } // Check if this shell has a modal child Shell[] children = shell.getShells(); Shell modalChild = getModalChildExcluding(children, toExclude); if (modalChild != null) { return modalChild; } // If not, check if this shell is modal itself if (shell.isVisible() && (shell.getStyle() & modal) != 0) { return shell; } } return null; } /** * Utility method to get the best parenting possible for a dialog. If there * is a modal shell create it so as to avoid two modal dialogs. If not then * return the shell of the active workbench window. If neither can be found * return null. * * @return Shell or <code>null</code> */ public static Shell getDefaultParent() { Shell modal = getModalShellExcluding(null); if (modal != null) { return modal; } return getNonModalShell(); } /** * Get the active non modal shell. If there isn't one return null. * * @return Shell */ public static Shell getNonModalShell() { if (application == null) { // better safe than sorry return null; } MWindow window = application.getSelectedElement(); if (window != null) { Object widget = window.getWidget(); if (widget instanceof Shell) { return (Shell) widget; } } for (MWindow child : application.getChildren()) { Object widget = child.getWidget(); if (widget instanceof Shell) { return (Shell) widget; } } return null; } /** * Get the shell provider to use in the progress support dialogs. This * provider will try to always parent off of an existing modal shell. If * there isn't one it will use the current workbench window. * * @return IShellProvider */ static IShellProvider getShellProvider() { return new IShellProvider() { /* * (non-Javadoc) * * @see org.eclipse.jface.window.IShellProvider#getShell() */ public Shell getShell() { return getDefaultParent(); } }; } }