Java tutorial
/******************************************************************************* * Copyright (c) 2004, 2015 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation * Alexander Kurtakov <akurtako@redhat.com> - Bug 459761 *******************************************************************************/ package org.eclipse.jface.bindings.keys; import java.util.Locale; import java.util.StringTokenizer; import org.eclipse.jface.bindings.Trigger; import org.eclipse.jface.bindings.keys.formatting.KeyFormatterFactory; import org.eclipse.jface.util.Util; /** * <p> * A <code>KeyStroke</code> is defined as an optional set of modifier keys * followed optionally by a natural key. A <code>KeyStroke</code> is said to * be complete if it contains a natural key. A natural key is any Unicode * character (e.g., "backspace", etc.), any character belonging to a natural * language (e.g., "A", "1", "[", etc.), or any special control character * specific to computers (e.g., "F10", "PageUp", etc.). * </p> * <p> * All <code>KeyStroke</code> objects have a formal string representation * available via the <code>toString()</code> method. There are a number of * methods to get instances of <code>KeyStroke</code> objects, including one * which can parse this formal string representation. * </p> * <p> * All <code>KeyStroke</code> objects, via the <code>format()</code> method, * provide a version of their formal string representation translated by * platform and locale, suitable for display to a user. * </p> * <p> * <code>KeyStroke</code> objects are immutable. Clients are not permitted to * extend this class. * </p> * * @since 3.1 */ public final class KeyStroke extends Trigger { /** * The delimiter between multiple keys in a single key strokes -- expressed * in the formal key stroke grammar. This is not to be displayed to the * user. It is only intended as an internal representation. */ public static final String KEY_DELIMITER = "\u002B"; //$NON-NLS-1$ /** * The set of delimiters for <code>Key</code> objects allowed during * parsing of the formal string representation. */ public static final String KEY_DELIMITERS = KEY_DELIMITER; /** * The representation for no key. */ public static final int NO_KEY = 0; /** * Creates an instance of <code>KeyStroke</code> given a natural key. * * @param naturalKey * the natural key. The format of this integer is defined by * whichever widget toolkit you are using; <code>NO_KEY</code> * always means no natural key. * @return a key stroke. This key stroke will have no modifier keys. * Guaranteed not to be <code>null</code>. * @see SWTKeySupport */ public static final KeyStroke getInstance(final int naturalKey) { return new KeyStroke(NO_KEY, naturalKey); } /** * Creates an instance of <code>KeyStroke</code> given a set of modifier keys * and a natural key. * * @param modifierKeys * the modifier keys. The format of this integer is defined by * whichever widget toolkit you are using; <code>NO_KEY</code> * always means no modifier keys. * @param naturalKey * the natural key. The format of this integer is defined by * whichever widget toolkit you are using; <code>NO_KEY</code> * always means no natural key. * @return a key stroke. Guaranteed not to be <code>null</code>. * @see SWTKeySupport */ public static final KeyStroke getInstance(final int modifierKeys, final int naturalKey) { return new KeyStroke(modifierKeys, naturalKey); } /** * Creates an instance of <code>KeyStroke</code> by parsing a given a formal * string representation. * * @param string * the formal string representation to parse. * @return a key stroke. Guaranteed not to be <code>null</code>. * @throws ParseException * if the given formal string representation could not be parsed * to a valid key stroke. */ public static final KeyStroke getInstance(final String string) throws ParseException { if (string == null) { throw new NullPointerException("Cannot parse a null string"); //$NON-NLS-1$ } final IKeyLookup lookup = KeyLookupFactory.getDefault(); int modifierKeys = NO_KEY; int naturalKey = NO_KEY; final StringTokenizer stringTokenizer = new StringTokenizer(string, KEY_DELIMITERS, true); int i = 0; while (stringTokenizer.hasMoreTokens()) { String token = stringTokenizer.nextToken(); if (i % 2 == 0) { if (stringTokenizer.hasMoreTokens()) { token = token.toUpperCase(Locale.ENGLISH); final int modifierKey = lookup.formalModifierLookup(token); if (modifierKey == NO_KEY) { throw new ParseException( "Cannot create key stroke with duplicate or non-existent modifier key: " //$NON-NLS-1$ + token); } modifierKeys |= modifierKey; } else if (token.length() == 1) { naturalKey = token.charAt(0); } else { token = token.toUpperCase(Locale.ENGLISH); naturalKey = lookup.formalKeyLookup(token); } } i++; } return new KeyStroke(modifierKeys, naturalKey); } /** * An integer representation of the modifier keys; <code>NO_KEY</code> * means that there is no modifier key. */ private final int modifierKeys; /** * The natural key for this key stroke. This value is <code>NO_KEY</code> * if the key stroke is incomplete (i.e., has no natural key). */ private final int naturalKey; /** * Constructs an instance of <code>KeyStroke</code> given a set of * modifier keys and a natural key. * * @param modifierKeys * the modifier keys. The format of this integer is defined by * whichever widget toolkit you are using; <code>NO_KEY</code> * always means no modifier keys. * @param naturalKey * the natural key. The format of this integer is defined by * whichever widget toolkit you are using; <code>NO_KEY</code> * always means no natural key. * @see SWTKeySupport */ private KeyStroke(final int modifierKeys, final int naturalKey) { this.modifierKeys = modifierKeys; this.naturalKey = naturalKey; } @Override public final int compareTo(final Object object) { final KeyStroke keyStroke = (KeyStroke) object; int compareTo = Util.compare(modifierKeys, keyStroke.modifierKeys); if (compareTo == 0) { compareTo = Util.compare(naturalKey, keyStroke.naturalKey); } return compareTo; } @Override public final boolean equals(final Object object) { if (!(object instanceof KeyStroke)) { return false; } final KeyStroke keyStroke = (KeyStroke) object; if (modifierKeys != keyStroke.modifierKeys) { return false; } return (naturalKey == keyStroke.naturalKey); } /** * Formats this key stroke into the current default look. * * @return A string representation for this key stroke using the default * look; never <code>null</code>. */ public final String format() { return KeyFormatterFactory.getDefault().format(this); } /** * Returns the modifier keys for this key stroke. * * @return the bit mask of modifier keys; <code>NO_KEY</code> means that * there is no modifier key. */ public final int getModifierKeys() { return modifierKeys; } /** * Returns the natural key for this key stroke. * * @return The natural key for this key stroke. This value is * <code>NO_KEY</code> if the key stroke is incomplete (i.e., has * no natural key). */ public final int getNaturalKey() { return naturalKey; } @Override public final int hashCode() { return (modifierKeys << 4) + naturalKey; } /** * Returns whether or not this key stroke is complete. Key strokes are * complete iff they have a natural key which is not <code>NO_KEY</code>. * * @return <code>true</code>, iff the key stroke is complete. */ public final boolean isComplete() { return (naturalKey != NO_KEY); } /** * Returns the formal string representation for this key stroke. * * @return The formal string representation for this key stroke. Guaranteed * not to be <code>null</code>. */ @Override public final String toString() { return KeyFormatterFactory.getFormalKeyFormatter().format(this); } }