001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 *
019 * $Id$
020 */
021
022package org.nuxeo.osgi.application;
023
024import java.io.File;
025import java.io.IOException;
026import java.util.Collection;
027import java.util.List;
028import java.util.jar.JarFile;
029
030import org.nuxeo.osgi.BundleFile;
031import org.nuxeo.osgi.DirectoryBundleFile;
032import org.nuxeo.osgi.JarBundleFile;
033
034/**
035 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
036 */
037public class ClassPathScanner {
038
039    protected boolean scanForNestedJARs = true;
040
041    protected final Callback callback;
042
043    /**
044     * If set points to a set of path prefixes to be excluded form bundle processing
045     */
046    protected String[] blackList;
047
048    public ClassPathScanner(Callback callback) {
049        this.callback = callback;
050    }
051
052    public ClassPathScanner(Callback callback, boolean scanForNestedJars, String[] blackList) {
053        this.callback = callback;
054        scanForNestedJARs = scanForNestedJars;
055        this.blackList = blackList;
056    }
057
058    public void setScanForNestedJARs(boolean scanForNestedJars) {
059        scanForNestedJARs = scanForNestedJars;
060    }
061
062    public void scan(List<File> classPath) {
063        for (File file : classPath) {
064            scan(file);
065        }
066    }
067
068    public void scan(File file) {
069        String path = file.getAbsolutePath();
070        if (!(path.endsWith(".jar") || path.endsWith(".rar") || path.endsWith(".sar") || path.endsWith("_jar")
071                || path.endsWith("_rar") || path.endsWith("_sar"))) {
072            return;
073        }
074        if (blackList != null) {
075            for (String prefix : blackList) {
076                if (path.startsWith(prefix)) {
077                    return;
078                }
079            }
080        }
081        try {
082            BundleFile bf;
083            if (file.isFile()) {
084                JarFile jar = new JarFile(file);
085                bf = new JarBundleFile(jar);
086            } else if (file.isDirectory()) {
087                bf = new DirectoryBundleFile(file);
088            } else {
089                return;
090            }
091            File nestedJARsDir;
092            if (bf.getSymbolicName() == null) { // a regular jar
093                nestedJARsDir = callback.handleJar(bf);
094            } else { // an osgi bundle
095                nestedJARsDir = callback.handleBundle(bf);
096            }
097            if (nestedJARsDir != null) {
098                Collection<BundleFile> nested = extractNestedJars(bf, nestedJARsDir);
099                if (nested != null) {
100                    for (BundleFile nestedJar : nested) {
101                        callback.handleNestedJar(nestedJar);
102                    }
103                }
104            }
105        } catch (IOException e) {
106            // ignore exception since some manifest may be invalid (invalid ClassPath entries) etc.
107        }
108    }
109
110    public Collection<BundleFile> extractNestedJars(BundleFile bf, File nestedBundlesDir) throws IOException {
111        Collection<BundleFile> bundles = null;
112        if (scanForNestedJARs) {
113            bundles = bf.findNestedBundles(nestedBundlesDir);
114        } else { // use manifest to find nested jars
115            bundles = bf.getNestedBundles(nestedBundlesDir);
116        }
117        if (bundles != null && bundles.isEmpty()) {
118            bundles = null;
119        }
120        return bundles;
121    }
122
123    public interface Callback {
124
125        /**
126         * A nested JAR was found on the class path. Usually a callback should handle this by adding the JAR to a class
127         * loader
128         * <p>
129         * The callback should return a directory to be used to extract nested JARs from this JAR.
130         * <p>
131         * The callback may return null to skip nested JAR extraction
132         *
133         * @param bf the JAR found
134         */
135        void handleNestedJar(BundleFile bf);
136
137        /**
138         * A JAR was found on the class path. Usually a callback should handle this by adding the JAR to a class loader.
139         * <p>
140         * The callback should return a directory to be used to extract nested JARs from this JAR.
141         * <p>
142         * The callback may return null to skip nested JAR extraction.
143         *
144         * @param bf the JAR found
145         * @return the folder to be used to extract JARs or null to skip extraction
146         */
147        File handleJar(BundleFile bf);
148
149        /**
150         * A Bundle was found on the class path. Usually a callback should handle this by adding the Bundle to a class
151         * loader and installing it in an OSGi framework
152         * <p>
153         * The callback should return a directory to be used to extract nested JARs from this JAR.
154         * <p>
155         * The callback may return null to skip nested JAR extraction.
156         *
157         * @param bf the JAR found
158         * @return the folder to be used to extract JARs or null to skip extraction
159         */
160        File handleBundle(BundleFile bf);
161
162    }
163
164}