/*******************************************************************************
 * Copyright (c) 2000, 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.ui.internal.keys;

import java.util.Comparator;
import java.util.ResourceBundle;

import org.eclipse.ui.internal.util.Util;
import org.eclipse.ui.keys.Key;
import org.eclipse.ui.keys.KeySequence;
import org.eclipse.ui.keys.KeyStroke;
import org.eclipse.ui.keys.ModifierKey;

/**
 * A key formatter providing the Emacs-style accelerators using single letters
 * to represent the modifier keys.
 * 
 * @since 3.0
 */
public class EmacsKeyFormatter extends AbstractKeyFormatter {

    /**
     * A comparator that guarantees that modifier keys will be sorted the same
     * across different platforms.
     */
    private static final Comparator EMACS_MODIFIER_KEY_COMPARATOR = new AlphabeticModifierKeyComparator();

    /**
     * The resource bundle used by <code>format()</code> to translate formal
     * string representations by locale.
     */
    private final static ResourceBundle RESOURCE_BUNDLE = ResourceBundle
            .getBundle(EmacsKeyFormatter.class.getName());

    /**
     * Formats an individual key into a human readable format. This converts
     * the key into a format similar to Xemacs.
     * 
     * @param key
     *            The key to format; must not be <code>null</code>.
     * @return The key formatted as a string; should not be <code>null</code>.
     */
    public String format(Key key) {
        if (key instanceof ModifierKey) {
            String formattedName = Util.translateString(RESOURCE_BUNDLE, key
                    .toString(), null, false, false);
            if (formattedName != null) {
                return formattedName;
            }
        }

        return super.format(key).toLowerCase();
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.keys.AbstractKeyFormatter#getKeyDelimiter()
     */
    protected String getKeyDelimiter() {
        return Util.translateString(RESOURCE_BUNDLE, KEY_DELIMITER_KEY,
                KeyStroke.KEY_DELIMITER, false, false);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.keys.AbstractKeyFormatter#getKeyStrokeDelimiter()
     */
    protected String getKeyStrokeDelimiter() {
        return Util.translateString(RESOURCE_BUNDLE, KEY_STROKE_DELIMITER_KEY,
                KeySequence.KEY_STROKE_DELIMITER, false, false);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.keys.AbstractKeyFormatter#getModifierKeyComparator()
     */
    protected Comparator getModifierKeyComparator() {
        return EMACS_MODIFIER_KEY_COMPARATOR;
    }

}
