/* * ModuleLoader - A generic, policy-driven class loader. * 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.moduleloader.search.compatibility;import org.ungoverned.moduleloader.search.CompatibilityPolicy;/** * This class implements a simple version numbering compatibility policy for the * <tt>ImportSearchPolicy</tt> where only exact version numbers are considered * to be compatible.  This policy simply returns the result of * "<tt>leftId.equals(rightId) && leftVersion.equals(rightVersion)</tt>". Any * calls to the <tt>compare()</tt> method result in an exception since this * policy has no basis for comparing identifiers and versions. * @see org.ungoverned.moduleloader.search.CompatibilityPolicy * @see org.ungoverned.moduleloader.search.ImportSearchPolicy**/public class ExactCompatibilityPolicy implements CompatibilityPolicy{    /**     * Compares two versioned identifiers, but since this policy has     * no understanding of how to compare identifiers, it always throws     * an <tt>IllegalArgumentException</tt>.     * @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)    {        throw new IllegalArgumentException("Identifiers are not comparable.");    }    /**     * Returns whether the first import/export target is compatible     * with the second. This method simply uses the "<tt>equals()</tt>" method     * to test both the identifier and the verison number.     * @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)    {        return leftId.equals(rightId) && leftVersion.equals(rightVersion);    }}