001/*******************************************************************************
002 * This software is provided as a supplement to the authors' textbooks on digital
003 * image processing published by Springer-Verlag in various languages and editions.
004 * Permission to use and distribute this software is granted under the BSD 2-Clause
005 * "Simplified" License (see http://opensource.org/licenses/BSD-2-Clause).
006 * Copyright (c) 2006-2023 Wilhelm Burger, Mark J. Burge. All rights reserved.
007 * Visit https://imagingbook.com for additional details.
008 ******************************************************************************/
009package imagingbook.core;
010
011import java.net.URI;
012import java.net.URISyntaxException;
013import java.nio.file.Path;
014import java.nio.file.Paths;
015
016public abstract class ClassUtils {
017
018
019    public static String getModuleFromPackage(Class<?> clazz) {
020        Package pkg = clazz.getPackage();
021        if (pkg == null)
022            return null;
023        String specs = pkg.getSpecificationTitle();
024        if (specs == null)
025            return null;
026        int k = specs.lastIndexOf(':');
027        if (k < 0) {
028            return null;
029        }
030        return specs.substring(specs.lastIndexOf(':') + 1);
031    }
032
033    /**
034     * Tries to discover the name of the module defining the specified class.
035     * Call with arguments (clazz, "imagingbook-public").
036     *
037     * @param clazz a class instance
038     * @param projectName the name of the containing project
039     * @return the module name or {@code null} if not found.
040     */
041    public static String getModuleFromClasspath(Class<?> clazz, String projectName) {
042        Path ppp = Paths.get(projectName);
043        String moduleName = null;
044        try {
045            URI uri = clazz.getProtectionDomain().getCodeSource().getLocation().toURI();
046            if (uri != null) {
047                Path p = Paths.get(uri);
048                int n = p.getNameCount();
049                int k = -1;
050                // find 'projectName' in path components:
051                for (int i = 0; i < n; i++) {
052                    if (p.getName(i).equals(ppp)) {
053                        k = i + 1;
054                        break;
055                    }
056                }
057                // the following component should be the module part
058                if (k >= 0 && k < n-1) {
059                    moduleName = p.getName(k).toString();
060                }
061            }
062        } catch (URISyntaxException e) { }
063        return moduleName;
064    }
065
066
067    // -----------------------------------------------------------------
068
069    public static void main(String[] args) throws URISyntaxException {
070
071        Class<?> clazz = FileUtils.class;
072        String specs = clazz.getPackage().getSpecificationTitle();
073        System.out.println("specs = " + specs);
074
075        System.out.println("module from class = " + clazz.getModule().getName());
076        System.out.println("module from package = " + getModuleFromPackage(clazz));
077        System.out.println("module from classpath = " + getModuleFromClasspath(clazz, "imagingbook-public"));
078
079    }
080}