/* * Oscar - An implementation of the OSGi framework. * Copyright (c) 2004, Richard S. Hall * All rights reserved. *   * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: *   *   * Redistributions of source code must retain the above copyright *     notice, this list of conditions and the following disclaimer. *   * 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. *   * Neither the name of the ungoverned.org nor the names of its *     contributors may be used to endorse or promote products derived *     from this software without specific prior written permission. *   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS 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 COPYRIGHT * OWNER OR 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. *  * Contact: Richard S. Hall (heavy@ungoverned.org) * Contributor(s): ***/package org.ungoverned.oscar;import org.ungoverned.moduleloader.search.CompatibilityPolicy;public class OSGiCompatibilityPolicy implements CompatibilityPolicy{    private Oscar m_oscar = null;    public OSGiCompatibilityPolicy(Oscar oscar)    {        m_oscar = oscar;    }    /**     * Compares two versioned identifiers.     * @param leftId the identifier to test for compatibility.     * @param leftVersion the version number to test for compatibility.     * @param rightId the identifier used as the compatibility base line.     * @param rightVersion the version used as the compatibility base line.     * @return <tt>0</tt> if the identifiers are equal, <tt>-1</tt> if the     *         left identifier is less then the right identifier, and <tt>1</tt>     *         if the left identifier is greater than the right identifier.     * @throws java.lang.IllegalArgumentException if the two identifiers     *         are not comparable, i.e., they refer to completely different     *         entities.    **/    public int compare(        Object leftId, Object leftVersion,        Object rightId, Object rightVersion)    {        if (isComparable(leftId, rightId))        {            return compareVersion((int[]) leftVersion, (int[]) rightVersion);        }        else        {            throw new IllegalArgumentException("Identifiers are not comparable.");        }    }    /**     * Returns whether the first import/export target is compatible     * with the second.     * @param leftId the identifier to test for compatibility.     * @param leftVersion the version number to test for compatibility.     * @param rightId the identifier used as the compatibility base line.     * @param rightVersion the version used as the compatibility base line.     * @return <tt>true</tt> if the left version number object is compatible     *         with the right version number object, otherwise <tt>false</tt>.    **/    public boolean isCompatible(        Object leftId, Object leftVersion,        Object rightId, Object rightVersion)    {        try {            // The OSGi spec says that identifiers are always backwards compatible.            return (compare(leftId, leftVersion, rightId, rightVersion) >= 0);        } catch (Exception ex) {            return false;        }    }    /**     * Returns whether the two identifiers are comparable. This method was     * intended to allow different policies of comparing imports to exports,     * such as allowing "wildcard" exports, but it does not fully work for     * that purpose and is possibly not necessary.     *      * @param leftId the first identifier to test.     * @param rightId the second identifier to test.     * @return <tt>true</tt> if the two identifiers are comparable,     *         <tt>false</tt> otherwise.    **/    private boolean isComparable(Object leftId, Object rightId)    {        return leftId.equals(rightId);    }    private int compareVersion(int[] left, int[] right)    {        if (left[0] > right[0])            return 1;        else if (left[0] < right[0])            return -1;        else if (left[1] > right[1])            return 1;        else if (left[1] < right[1])            return -1;        else if (left[2] > right[2])            return 1;        else if (left[2] < right[2])            return -1;        return 0;    }}