find Annotated Classes from jar file - Java java.lang.annotation

Java examples for java.lang.annotation:Class Annotation

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Description

find Annotated Classes from jar file

Demo Code


//package com.java2s;
import java.io.File;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class Main {
    public static List<Class<?>> findAnnotatedClasses(
            Class<? extends Annotation> an, File[] locations)
            throws ClassNotFoundException, IOException {
        List<Class<?>> ret = new ArrayList<Class<?>>();

        for (File loc : locations) {
            if (loc.isDirectory()) {
                scanDirectory("", loc, an, ret);
            } else {
                scanJar(loc, an, ret);//from  w ww. j a  v a  2 s  .  c  om
            }
        }

        return ret;
    }

    private static void scanDirectory(String pkg, File dir,
            Class<? extends Annotation> an, List<Class<?>> entries)
            throws ClassNotFoundException {
        File contents[] = dir.listFiles();
        for (File f : contents) {
            if (f.isDirectory()) {
                String newPkg = "";
                if (pkg.length() > 0) {
                    newPkg = pkg + '.' + f.getName();
                } else {
                    newPkg = f.getName();
                }
                scanDirectory(newPkg, f, an, entries);
            } else {
                if (f.getName().endsWith(".class")) {
                    String clName = pkg
                            + '.'
                            + f.getName().substring(0,
                                    f.getName().length() - 6);
                    Class<?> cl = Thread.currentThread()
                            .getContextClassLoader().loadClass(clName);
                    if ((cl.isAnnotationPresent(an))
                            && (!entries.contains(cl))) {
                        entries.add(cl);
                    }
                }
            }
        }
    }

    private static void scanJar(File file, Class<? extends Annotation> an,
            List<Class<?>> ret) throws IOException, ClassNotFoundException {
        JarFile jar = null;

        try {
            jar = new JarFile(file);

            Enumeration<JarEntry> entries = jar.entries();
            while (entries.hasMoreElements()) {
                JarEntry entry = entries.nextElement();
                if (entry.getName().endsWith(".class")) {
                    String name = entry.getName().substring(0,
                            entry.getName().length() - 6);
                    name = name.replace('/', '.');
                    try {
                        Class<?> cl = Thread.currentThread()
                                .getContextClassLoader().loadClass(name);
                        if ((cl.isAnnotationPresent(an))
                                && (!ret.contains(cl))) {
                            ret.add(cl);
                        }
                    } catch (NoClassDefFoundError e) {
                        // No-op if couldn't find the class.
                    }
                }
            }
        } finally {
            if (jar != null) {
                try {
                    jar.close();
                } catch (Exception e) {
                }
            }
        }
    }
}

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