001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *  http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.xbean.osgi.bundle.util;
021
022import java.net.URL;
023import java.util.Collections;
024import java.util.Dictionary;
025import java.util.Enumeration;
026import java.util.LinkedHashSet;
027import java.util.List;
028
029import org.osgi.framework.Bundle;
030import org.osgi.framework.BundleReference;
031import org.osgi.framework.Constants;
032import org.osgi.framework.ServiceReference;
033import org.osgi.service.packageadmin.ExportedPackage;
034import org.osgi.service.packageadmin.PackageAdmin;
035
036/**
037 * @version $Rev: 937957 $ $Date: 2010-04-26 10:00:08 +0200 (lun. 26 avril 2010) $
038 */
039public class BundleUtils {
040
041    public static boolean canStart(Bundle bundle) {
042        return (bundle.getState() != Bundle.UNINSTALLED) && (bundle.getState() != Bundle.STARTING) && (!isFragment(bundle));
043    }
044
045    public static boolean canStop(Bundle bundle) {
046        return (bundle.getState() != Bundle.UNINSTALLED) && (bundle.getState() != Bundle.STOPPING) && (!isFragment(bundle));
047    }
048
049    public static boolean canUninstall(Bundle bundle) {
050        return bundle.getState() != Bundle.UNINSTALLED;
051    }
052
053    public static boolean isFragment(Bundle bundle) {
054        Dictionary headers = bundle.getHeaders();
055        return (headers != null && headers.get(Constants.FRAGMENT_HOST) != null);
056    }
057
058    /**
059     * Returns bundle (if any) associated with current thread's context classloader.
060     *
061     * @param unwrap if true and if the bundle associated with the context classloader is a
062     *        {@link DelegatingBundle}, this function will return the main application bundle
063     *        backing with the {@link DelegatingBundle}. Otherwise, the bundle associated with
064     *        the context classloader is returned as is. See {@link BundleClassLoader#getBundle(boolean)}
065     *        for more information.
066     * @return The bundle associated with the current thread's context classloader. Might be null.
067     */
068    public static Bundle getContextBundle(boolean unwrap) {
069        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
070        if (classLoader instanceof BundleClassLoader) {
071            return ((BundleClassLoader) classLoader).getBundle(unwrap);
072        } else if (classLoader instanceof BundleReference) {
073            return ((BundleReference) classLoader).getBundle();
074        } else {
075            return null;
076        }
077    }
078
079    /**
080     * Works like {@link Bundle#getEntryPaths(String)} but also returns paths
081     * in attached fragment bundles.
082     *
083     * @param bundle
084     * @param name
085     * @return
086     */
087    public static Enumeration<String> getEntryPaths(Bundle bundle, String name) {
088        Enumeration<URL> entries = bundle.findEntries(name, null, false);
089        if (entries == null) {
090            return null;
091        }
092        LinkedHashSet<String> paths = new LinkedHashSet<String>();
093        while (entries.hasMoreElements()) {
094            URL url = entries.nextElement();
095            String path = url.getPath();
096            if (path.startsWith("/")) {
097                path = path.substring(1);
098            }
099            paths.add(path);
100        }
101        return Collections.enumeration(paths);
102    }
103
104    /**
105     * Works like {@link Bundle#getEntry(String)} but also checks
106     * attached fragment bundles for the given entry.
107     *
108     * @param bundle
109     * @param name
110     * @return
111     */
112    public static URL getEntry(Bundle bundle, String name) {
113        if (name.equals("/")) {
114            return bundle.getEntry(name);
115        } else if (name.endsWith("/")) {
116            name = name.substring(0, name.length() - 1);
117        }
118        String path;
119        String pattern;
120        int pos = name.lastIndexOf("/");
121        if (pos == -1) {
122            path = "/";
123            pattern = name;
124        } else if (pos == 0) {
125            path = "/";
126            pattern = name.substring(1);
127        } else {
128            path = name.substring(0, pos);
129            pattern = name.substring(pos + 1);
130        }
131        Enumeration<URL> entries = bundle.findEntries(path, pattern, false);
132        if (entries != null && entries.hasMoreElements()) {
133            return entries.nextElement();
134        } else {
135            return null;
136        }
137    }
138
139    public static LinkedHashSet<Bundle> getWiredBundles(Bundle bundle) {
140        ServiceReference reference = bundle.getBundleContext().getServiceReference(PackageAdmin.class.getName());
141        PackageAdmin packageAdmin = (PackageAdmin) bundle.getBundleContext().getService(reference);
142        try {
143            return getWiredBundles(packageAdmin, bundle);
144        } finally {
145            bundle.getBundleContext().ungetService(reference);
146        }
147    }
148
149    public static LinkedHashSet<Bundle> getWiredBundles(PackageAdmin packageAdmin, Bundle bundle) {
150        BundleDescription description = new BundleDescription(bundle.getHeaders());
151        // handle static wire via Import-Package
152        List<BundleDescription.ImportPackage> imports = description.getExternalImports();
153        LinkedHashSet<Bundle> wiredBundles = new LinkedHashSet<Bundle>();
154        for (BundleDescription.ImportPackage packageImport : imports) {
155            ExportedPackage[] exports = packageAdmin.getExportedPackages(packageImport.getName());
156            Bundle wiredBundle = getWiredBundle(bundle, exports);
157            if (wiredBundle != null) {
158                wiredBundles.add(wiredBundle);
159            }
160        }
161        // handle dynamic wire via DynamicImport-Package
162        if (!description.getDynamicImportPackage().isEmpty()) {
163            for (Bundle b : bundle.getBundleContext().getBundles()) {
164                if (!wiredBundles.contains(b)) {
165                    ExportedPackage[] exports = packageAdmin.getExportedPackages(b);
166                    Bundle wiredBundle = getWiredBundle(bundle, exports);
167                    if (wiredBundle != null) {
168                        wiredBundles.add(wiredBundle);
169                    }
170                }
171            }
172        }
173        return wiredBundles;
174    }
175
176    private static Bundle getWiredBundle(Bundle bundle, ExportedPackage[] exports) {
177        if (exports != null) {
178            for (ExportedPackage exportedPackage : exports) {
179                Bundle[] importingBundles = exportedPackage.getImportingBundles();
180                if (importingBundles != null) {
181                    for (Bundle importingBundle : importingBundles) {
182                        if (importingBundle == bundle) {
183                            return exportedPackage.getExportingBundle();
184                        }
185                    }
186                }
187            }
188        }
189        return null;
190    }
191}