001/*
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v2.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014
015package ch.qos.logback.classic.util;
016
017import ch.qos.logback.classic.ClassicConstants;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.util.Properties;
022
023/**
024 * Utility class for retrieving version information for the "logback-classic" module.
025 * This class provides functionality to read and parse self-declared properties files
026 * containing version metadata specific to the logback-classic module.
027 *
028 * It includes methods to locate the version properties file, extract the version string
029 * based on specified conventions, and return the retrieved information.
030 */
031public class ClassicVersionUtil {
032
033    static String CLASSIC_MODULE_NAME = "logback-classic";
034    static String CLASSIC_MODULE_VERSION_PROPERTIES_FILE = CLASSIC_MODULE_NAME + "-version.properties";
035    static String CLASSIC_MODULE_VERSION_PROPERTY_KEY = CLASSIC_MODULE_NAME + "-version";
036
037
038    // Code copied from VersionUtil. It must be located in the encompassing module and cannot be
039    // shared.
040    //
041    // Retrieving version information by self-declared properties solves the issue of collapsed
042    // MANIFEST.MF files as encountered in fat-jars.
043    //
044    // this code further assumes that the properties file is located in the same package as the aClass
045    // parameter.
046    static String getVersionBySelfDeclaredProperties(Class<?> aClass, String moduleName) {
047        Properties props = new Properties();
048        // example propertiesFileName: logback-core-version.properties
049        //
050        String propertiesFileName = moduleName + "-version.properties";
051        String propertyKey = moduleName+"-version";
052        try (InputStream is = aClass.getResourceAsStream(propertiesFileName)) {
053            if (is != null) {
054                props.load(is);
055                return props.getProperty(propertyKey);
056            } else {
057                return null;
058            }
059        } catch (IOException e) {
060            return null;
061        }
062    }
063
064    /**
065     * Retrieves the version information for the "logback-classic" module based on its self-declared properties.
066     * The method looks for a properties file named "logback-classic-version.properties" within the classpath,
067     * reads its contents, and fetches the value associated with the "logback-classic-version" key.
068     *
069     * <p>Note that the Class.getResourceAsStream() method checks that the resource is open to the
070     * caller. This entails that the caller must be in the same module as the properties file.
071     * </p>
072     *
073     * @return the version string of the "logback-classic" module if found, or null if the properties file or version
074     *         key is not present or an error occurs while reading the properties file.
075     *
076     * @since 1.5.26
077     */
078    static public String getVersionBySelfDeclaredProperties() {
079        Properties props = new Properties();
080
081        try (InputStream is = ClassicConstants.class.getResourceAsStream(CLASSIC_MODULE_VERSION_PROPERTIES_FILE)) {
082            if (is != null) {
083                props.load(is);
084                return props.getProperty(CLASSIC_MODULE_VERSION_PROPERTY_KEY);
085            } else {
086                return null;
087            }
088        } catch (IOException e) {
089            return null;
090        }
091    }
092
093}