This software is distributed and should be used on terms of Apache software license. In short, it is free of charge, and unrestricted for commercial use as well. Full license text can be found here:

    The ObjectStyle Group Software License, version 1.1
    ObjectStyle Group - http://objectstyle.org/

    Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
    of the software. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    3. The end-user documentation included with the redistribution, if any,
       must include the following acknowlegement:
       "This product includes software developed by independent contributors
       and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
       Alternately, this acknowlegement may appear in the software itself,
       if and wherever such third-party acknowlegements normally appear.

    4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
       or promote products derived from this software without prior written
       permission. For written permission, email
       "andrus at objectstyle dot org".

    5. Products derived from this software may not be called "ObjectStyle"
       or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
       names without prior written permission.

    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
    ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.
    ====================================================================

    This software consists of voluntary contributions made by many
    individuals and hosted on ObjectStyle Group web site.  For more
    information on the ObjectStyle Group, please see http://objectstyle.org/.