com.acciente.commons.loader.ClassFinder.java Source code

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Here is the source code for com.acciente.commons.loader.ClassFinder.java

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/*
 * Copyright 2008-2013 Acciente, LLC
 *
 * Acciente, LLC licenses this file to you 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 com.acciente.commons.loader;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.regex.Pattern;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * ClassFinder
 *
 * @author Adinath Raveendra Raj
 * @created May 25, 2009
 */
public class ClassFinder {
    private static final String URL_PREFIX_FILE = "file:/";
    private static final String URL_PREFIX_JARFILE = "jar:file:/";

    private static final String URL_DELIM_JARFILE = ".jar!/";

    private static final Log __oLog;

    static {
        __oLog = LogFactory.getLog(ClassFinder.class);
    }

    public static Set find(ClassLoader oClassLoader, String[] asPackageNames, Pattern oClassPattern)
            throws IOException {
        Set oClassNameSet = new HashSet();

        for (int i = 0; i < asPackageNames.length; i++) {
            String sPackageName = asPackageNames[i];

            Enumeration oResources = oClassLoader.getResources(sPackageName.replace('.', '/'));

            if (!oResources.hasMoreElements()) {
                __oLog.info("classloader scan for package: " + sPackageName + " found no resources!");
            }

            while (oResources.hasMoreElements()) {
                String sResourceURL = URLDecoder.decode(((URL) oResources.nextElement()).toString(), "UTF-8");

                if (sResourceURL.startsWith(URL_PREFIX_JARFILE)) {
                    int iDelimPos = sResourceURL.indexOf(URL_DELIM_JARFILE);

                    if (iDelimPos != -1) {
                        File oJarFile = new File(sResourceURL.substring(URL_PREFIX_JARFILE.length() - 1,
                                iDelimPos + ".jar".length()));

                        __oLog.info("scanning jar: " + oJarFile);

                        findInJar(oJarFile, sPackageName, oClassPattern, oClassNameSet);
                    }
                } else if (sResourceURL.startsWith(URL_PREFIX_FILE)) {
                    File oDirectory = new File(sResourceURL.substring(URL_PREFIX_FILE.length() - 1));

                    __oLog.info("scanning dir: " + oDirectory);

                    findInDirectory(oDirectory, sPackageName, oClassPattern, oClassNameSet);
                }
            }
        }

        // if the classloader is a ReloadingClassLoader the above loop would have processed the classed reachable via
        // the parent classloader, now we process the classes reachable via this classloader
        if (oClassLoader instanceof ReloadingClassLoader) {
            __oLog.info("reloading classloader detected, scanning...");

            ReloadingClassLoader oReloadingClassLoader = (ReloadingClassLoader) oClassLoader;

            for (Iterator oClassDefLoaderIter = oReloadingClassLoader.getClassDefLoaders()
                    .iterator(); oClassDefLoaderIter.hasNext();) {
                ClassDefLoader oClassDefLoader = (ClassDefLoader) oClassDefLoaderIter.next();

                Set oAddClassNameSet = oClassDefLoader.findClassNames(asPackageNames, oClassPattern);

                oClassNameSet.addAll(oAddClassNameSet);
            }
        }

        return oClassNameSet;
    }

    private static Set findInDirectory(File oPath, String sPackageName, Pattern oClassNamePattern,
            Set oClassNameSet) {
        File[] oFileList = oPath.listFiles();

        if (oFileList != null) {
            // iterate thru the classes in this directory
            for (int i = 0; i < oFileList.length; i++) {
                File oFile = oFileList[i];

                if (oFile.isDirectory()) {
                    if (sPackageName == null) {
                        findInDirectory(oFile, oFile.getName(), oClassNamePattern, oClassNameSet);
                    } else {
                        findInDirectory(oFile, sPackageName + "." + oFile.getName(), oClassNamePattern,
                                oClassNameSet);
                    }
                } else if (oFile.isFile() && oFile.getName().endsWith(".class")) {
                    String sClassname;

                    if (sPackageName == null) {
                        sClassname = getClassname(oFile);
                    } else {
                        sClassname = sPackageName + "." + getClassname(oFile);
                    }

                    if (oClassNamePattern.matcher(sClassname).matches()) {
                        oClassNameSet.add(sClassname);
                    }
                }
            }
        }

        return oClassNameSet;
    }

    private static Set findInJar(File oJarFile, String sPackageName, Pattern oClassNamePattern, Set oClassNameSet)
            throws IOException {
        ZipFile oZipFile;
        Enumeration oZipFileEntries;

        oZipFile = new ZipFile(oJarFile);
        oZipFileEntries = oZipFile.entries();

        while (oZipFileEntries.hasMoreElements()) {
            ZipEntry oZipFileEntry = (ZipEntry) oZipFileEntries.nextElement();
            String sClassname = getFQClassname(oZipFileEntry);

            if (!oZipFileEntry.isDirectory() && sClassname.startsWith(sPackageName)) {
                if (oClassNamePattern.matcher(sClassname).matches()) {
                    oClassNameSet.add(sClassname);
                }
            }
        }

        return oClassNameSet;
    }

    /**
     * Extracts a class name from a file name
     * @param oFile a file object to extract the class name
     * @return a classname (not fully qualified)
     */
    private static String getClassname(File oFile) {
        String sFileName = oFile.getName();

        if (sFileName.endsWith(".class")) {
            sFileName = sFileName.substring(0, sFileName.length() - ".class".length());
        }

        return sFileName;
    }

    /**
     * Extracts a fully qualified class name from a zip file entry
     * @param oZipFileEntry a zip file entry
     * @return a fully qualified classname
     */
    private static String getFQClassname(ZipEntry oZipFileEntry) {
        String sFileName = oZipFileEntry.getName();

        if (sFileName.endsWith(".class")) {
            sFileName = sFileName.substring(0, sFileName.length() - ".class".length());
        }

        return sFileName.replace('/', '.');
    }
}