/*******************************************************************************
 * Copyright (c) 2005 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 ******************************************************************************/

module dwtx.core.commands.common.NamedHandleObjectComparator;

// import java.util.Comparator;
import dwtx.core.commands.common.NotDefinedException;
import dwtx.core.commands.common.NamedHandleObject;
import dwtx.core.internal.commands.util.Util;
import dwt.dwthelper.utils;

/**
 * Comparator for instances of <code>NamedHandleObject</code> for display to
 * an end user. The comparison is based on the name of the instances.
 *
 * @since 3.2
 */
public class NamedHandleObjectComparator /+: Comparator+/ {

    /**
     * Compares to instances of NamedHandleObject based on their names. This is
     * useful is they are display to an end user.
     *
     * @param left
     *            The first obect to compare; may be <code>null</code>.
     * @param right
     *            The second object to compare; may be <code>null</code>.
     * @return <code>-1</code> if <code>left</code> is <code>null</code>
     *         and <code>right</code> is not <code>null</code>;
     *         <code>0</code> if they are both <code>null</code>;
     *         <code>1</code> if <code>left</code> is not <code>null</code>
     *         and <code>right</code> is <code>null</code>. Otherwise, the
     *         result of <code>left.compareTo(right)</code>.
     */
    public final int compare(Object left, Object right) {
        NamedHandleObject a = cast(NamedHandleObject) left;
        NamedHandleObject b = cast(NamedHandleObject) right;

        String aName = null;
        try {
            aName = a.getName();
        } catch (NotDefinedException e) {
            // Leave aName as null.
        }
        String bName = null;
        try {
            bName = b.getName();
        } catch (NotDefinedException e) {
            // Leave bName as null.
        }

        return Util.compare(aName, bName);
    }
}