/*******************************************************************************
* Copyright (c) 2004, 2006 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.jface.bindings.keys;
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 1.4
*/
public final class KeyStroke extends Trigger implements Comparable {
/**
* 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();
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();
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;
}
/*
* (non-Javadoc)
*
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
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;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#equals(java.lang.Object)
*/
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;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#hashCode()
*/
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>.
* @see java.lang.Object#toString()
*/
public final String toString() {
return KeyFormatterFactory.getFormalKeyFormatter().format(this);
}
}