Returns all classes from specified package. - Java Reflection

Java examples for Reflection:package

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Description

Returns all classes from specified package.

Demo Code


//package com.java2s;
import java.io.File;
import java.net.URL;
import java.util.ArrayList;

public class Main {
    /**/* w  ww.  ja va2 s  . c o  m*/
     * Returns all classes from specified package.
     * @param pckgname, full name of package.
     * @return array of classes.
     */
    public static Class[] getClasses(String packageName)
            throws ClassNotFoundException {
        ArrayList<Class> classes = new ArrayList<Class>();
        // Get a File object for the package
        File directory = null;
        try {
            ClassLoader classLoader = Thread.currentThread()
                    .getContextClassLoader();
            if (classLoader == null) {
                throw new ClassNotFoundException("Can't get class loader.");
            }
            //String path = '/' + pckgname.replace('.', '/');
            String path = packageName.replace('.', '/');
            URL resource = classLoader.getResource(path);
            if (resource == null) {
                throw new ClassNotFoundException("No resource for " + path);
            }
            directory = new File(resource.getFile());
        } catch (NullPointerException x) {
            throw new ClassNotFoundException(packageName + " (" + directory
                    + ") does not appear to be a valid package");
        }
        if (directory.exists()) {
            // Get the list of the files contained in the package
            String[] files = directory.list();
            for (int i = 0; i < files.length; i++) {
                // we are only interested in .class files
                if (files[i].endsWith(".class")) {
                    // removes the .class extension
                    classes.add(Class.forName(packageName + '.'
                            + files[i].substring(0, files[i].length() - 6)));
                }
            }
        } else {
            throw new ClassNotFoundException(packageName
                    + " does not appear to be a valid package");
        }
        Class[] classesA = new Class[classes.size()];
        classes.toArray(classesA);
        return classesA;
    }
}

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