| /* |
| * Copyright 2005 The Apache Software Foundation |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| package org.apache.osgi.moduleloader.search.compatibility; |
| |
| import org.apache.osgi.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.apache.osgi.moduleloader.search.CompatibilityPolicy |
| * @see org.apache.osgi.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); |
| } |
| } |