001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.config.plugins;
018
019import java.io.File;
020import java.io.FileInputStream;
021import java.io.FileNotFoundException;
022import java.io.IOException;
023import java.io.UnsupportedEncodingException;
024import java.lang.annotation.Annotation;
025import java.net.URI;
026import java.net.URL;
027import java.net.URLDecoder;
028import java.util.Arrays;
029import java.util.Collection;
030import java.util.Enumeration;
031import java.util.HashSet;
032import java.util.List;
033import java.util.Set;
034import java.util.jar.JarEntry;
035import java.util.jar.JarInputStream;
036
037import org.apache.logging.log4j.Logger;
038import org.apache.logging.log4j.core.helpers.Charsets;
039import org.apache.logging.log4j.core.helpers.Loader;
040import org.apache.logging.log4j.status.StatusLogger;
041import org.osgi.framework.FrameworkUtil;
042import org.osgi.framework.wiring.BundleWiring;
043
044/**
045 * <p>ResolverUtil is used to locate classes that are available in the/a class path and meet
046 * arbitrary conditions. The two most common conditions are that a class implements/extends
047 * another class, or that is it annotated with a specific annotation. However, through the use
048 * of the {@link Test} class it is possible to search using arbitrary conditions.</p>
049 *
050 * <p>A ClassLoader is used to locate all locations (directories and jar files) in the class
051 * path that contain classes within certain packages, and then to load those classes and
052 * check them. By default the ClassLoader returned by
053 *  {@code Thread.currentThread().getContextClassLoader()} is used, but this can be overridden
054 * by calling {@link #setClassLoader(ClassLoader)} prior to invoking any of the {@code find()}
055 * methods.</p>
056 *
057 * <p>General searches are initiated by calling the
058 * {@link #find(ResolverUtil.Test, String...)} method and supplying
059 * a package name and a Test instance. This will cause the named package <b>and all sub-packages</b>
060 * to be scanned for classes that meet the test. There are also utility methods for the common
061 * use cases of scanning multiple packages for extensions of particular classes, or classes
062 * annotated with a specific annotation.</p>
063 *
064 * <p>The standard usage pattern for the ResolverUtil class is as follows:</p>
065 *
066 *<pre>
067 *ResolverUtil&lt;ActionBean&gt; resolver = new ResolverUtil&lt;ActionBean&gt;();
068 *resolver.findImplementation(ActionBean.class, pkg1, pkg2);
069 *resolver.find(new CustomTest(), pkg1);
070 *resolver.find(new CustomTest(), pkg2);
071 *Collection&lt;ActionBean&gt; beans = resolver.getClasses();
072 *</pre>
073 *
074 * <p>This class was copied and modified from Stripes - http://stripes.mc4j.org/confluence/display/stripes/Home
075 * </p>
076 */
077public class ResolverUtil {
078    /** An instance of Log to use for logging in this class. */
079    private static final Logger LOGGER = StatusLogger.getLogger();
080
081    private static final String VFSZIP = "vfszip";
082
083    private static final String BUNDLE_RESOURCE = "bundleresource";
084
085    /** The set of matches being accumulated. */
086    private final Set<Class<?>> classMatches = new HashSet<Class<?>>();
087
088    /** The set of matches being accumulated. */
089    private final Set<URI> resourceMatches = new HashSet<URI>();
090
091    /**
092     * The ClassLoader to use when looking for classes. If null then the ClassLoader returned
093     * by Thread.currentThread().getContextClassLoader() will be used.
094     */
095    private ClassLoader classloader;
096
097    /**
098     * Provides access to the classes discovered so far. If no calls have been made to
099     * any of the {@code find()} methods, this set will be empty.
100     *
101     * @return the set of classes that have been discovered.
102     */
103    public Set<Class<?>> getClasses() {
104        return classMatches;
105    }
106
107    /**
108     * Returns the matching resources.
109     * @return A Set of URIs that match the criteria.
110     */
111    public Set<URI> getResources() {
112        return resourceMatches;
113    }
114
115
116    /**
117     * Returns the classloader that will be used for scanning for classes. If no explicit
118     * ClassLoader has been set by the calling, the context class loader will be used.
119     *
120     * @return the ClassLoader that will be used to scan for classes
121     */
122    public ClassLoader getClassLoader() {
123        return classloader != null ? classloader : (classloader = Loader.getClassLoader(ResolverUtil.class, null));
124    }
125
126    /**
127     * Sets an explicit ClassLoader that should be used when scanning for classes. If none
128     * is set then the context classloader will be used.
129     *
130     * @param classloader a ClassLoader to use when scanning for classes
131     */
132    public void setClassLoader(final ClassLoader classloader) { this.classloader = classloader; }
133
134    /**
135     * Attempts to discover classes that are assignable to the type provided. In the case
136     * that an interface is provided this method will collect implementations. In the case
137     * of a non-interface class, subclasses will be collected.  Accumulated classes can be
138     * accessed by calling {@link #getClasses()}.
139     *
140     * @param parent the class of interface to find subclasses or implementations of
141     * @param packageNames one or more package names to scan (including subpackages) for classes
142     */
143    public void findImplementations(final Class<?> parent, final String... packageNames) {
144        if (packageNames == null) {
145            return;
146        }
147
148        final Test test = new IsA(parent);
149        for (final String pkg : packageNames) {
150            findInPackage(test, pkg);
151        }
152    }
153
154    /**
155     * Attempts to discover classes who's name ends with the provided suffix. Accumulated classes can be
156     * accessed by calling {@link #getClasses()}.
157     *
158     * @param suffix The class name suffix to match
159     * @param packageNames one or more package names to scan (including subpackages) for classes
160     */
161    public void findSuffix(final String suffix, final String... packageNames) {
162        if (packageNames == null) {
163            return;
164        }
165
166        final Test test = new NameEndsWith(suffix);
167        for (final String pkg : packageNames) {
168            findInPackage(test, pkg);
169        }
170    }
171
172    /**
173     * Attempts to discover classes that are annotated with to the annotation. Accumulated
174     * classes can be accessed by calling {@link #getClasses()}.
175     *
176     * @param annotation the annotation that should be present on matching classes
177     * @param packageNames one or more package names to scan (including subpackages) for classes
178     */
179    public void findAnnotated(final Class<? extends Annotation> annotation, final String... packageNames) {
180        if (packageNames == null) {
181            return;
182        }
183
184        final Test test = new AnnotatedWith(annotation);
185        for (final String pkg : packageNames) {
186            findInPackage(test, pkg);
187        }
188    }
189
190    public void findNamedResource(final String name, final String... pathNames) {
191        if (pathNames == null) {
192            return;
193        }
194
195        final Test test = new NameIs(name);
196        for (final String pkg : pathNames) {
197            findInPackage(test, pkg);
198        }
199    }
200
201    /**
202     * Attempts to discover classes that pass the test. Accumulated
203     * classes can be accessed by calling {@link #getClasses()}.
204     *
205     * @param test the test to determine matching classes
206     * @param packageNames one or more package names to scan (including subpackages) for classes
207     */
208    public void find(final Test test, final String... packageNames) {
209        if (packageNames == null) {
210            return;
211        }
212
213        for (final String pkg : packageNames) {
214            findInPackage(test, pkg);
215        }
216    }
217
218    /**
219     * Scans for classes starting at the package provided and descending into subpackages.
220     * Each class is offered up to the Test as it is discovered, and if the Test returns
221     * true the class is retained.  Accumulated classes can be fetched by calling
222     * {@link #getClasses()}.
223     *
224     * @param test an instance of {@link Test} that will be used to filter classes
225     * @param packageName the name of the package from which to start scanning for
226     *        classes, e.g. {@code net.sourceforge.stripes}
227     */
228    public void findInPackage(final Test test, String packageName) {
229        packageName = packageName.replace('.', '/');
230        final ClassLoader loader = getClassLoader();
231        Enumeration<URL> urls;
232
233        try {
234            urls = loader.getResources(packageName);
235        } catch (final IOException ioe) {
236            LOGGER.warn("Could not read package: " + packageName, ioe);
237            return;
238        }
239
240        while (urls.hasMoreElements()) {
241            try {
242                final URL url = urls.nextElement();
243                String urlPath = extractPath(url);
244
245                LOGGER.info("Scanning for classes in [" + urlPath + "] matching criteria: " + test);
246                // Check for a jar in a war in JBoss
247                if (VFSZIP.equals(url.getProtocol())) {
248                    final String path = urlPath.substring(0, urlPath.length() - packageName.length() - 2);
249                    final URL newURL = new URL(url.getProtocol(), url.getHost(), path);
250                    @SuppressWarnings("resource")
251                    final JarInputStream stream = new JarInputStream(newURL.openStream());
252                    try {
253                        loadImplementationsInJar(test, packageName, path, stream);
254                    } finally {
255                        close(stream, newURL);
256                    }
257                } else if (BUNDLE_RESOURCE.equals(url.getProtocol())) {
258                    loadImplementationsInBundle(test, packageName);
259                } else {
260                    final File file = new File(urlPath);
261                    if (file.isDirectory()) {
262                        loadImplementationsInDirectory(test, packageName, file);
263                    } else {
264                        loadImplementationsInJar(test, packageName, file);
265                    }
266                }
267            } catch (final IOException ioe) {
268                LOGGER.warn("could not read entries", ioe);
269            }
270        }
271    }
272
273    String extractPath(final URL url) throws UnsupportedEncodingException {
274        String urlPath = url.getPath(); // same as getFile but without the Query portion
275        //System.out.println(url.getProtocol() + "->" + urlPath);
276        
277        // I would be surprised if URL.getPath() ever starts with "jar:" but no harm in checking
278        if (urlPath.startsWith("jar:")) {
279            urlPath = urlPath.substring(4);
280        }
281        // For jar: URLs, the path part starts with "file:"
282        if (urlPath.startsWith("file:")) {
283            urlPath = urlPath.substring(5);
284        }
285        // If it was in a JAR, grab the path to the jar
286        if (urlPath.indexOf('!') > 0) {
287            urlPath = urlPath.substring(0, urlPath.indexOf('!'));
288        }
289        
290        // LOG4J2-445
291        // Finally, decide whether to URL-decode the file name or not...
292        final String protocol = url.getProtocol();
293        final List<String> neverDecode = Arrays.asList(VFSZIP, BUNDLE_RESOURCE);
294        if (neverDecode.contains(protocol)) {
295            return urlPath;
296        }
297        if (new File(urlPath).exists()) {
298            // if URL-encoded file exists, don't decode it
299            return urlPath;
300        }
301        urlPath = URLDecoder.decode(urlPath, Charsets.UTF_8.name());
302        return urlPath;
303    }
304
305    private void loadImplementationsInBundle(final Test test, final String packageName) {
306        //Do not remove the cast on the next line as removing it will cause a compile error on Java 7.
307        final BundleWiring wiring = (BundleWiring) FrameworkUtil.getBundle(
308                ResolverUtil.class).adapt(BundleWiring.class);
309        final Collection<String> list = wiring.listResources(packageName, "*.class",
310            BundleWiring.LISTRESOURCES_RECURSE);
311        for (final String name : list) {
312            addIfMatching(test, name);
313        }
314    }
315
316
317    /**
318     * Finds matches in a physical directory on a filesystem.  Examines all
319     * files within a directory - if the File object is not a directory, and ends with <i>.class</i>
320     * the file is loaded and tested to see if it is acceptable according to the Test.  Operates
321     * recursively to find classes within a folder structure matching the package structure.
322     *
323     * @param test a Test used to filter the classes that are discovered
324     * @param parent the package name up to this directory in the package hierarchy.  E.g. if
325     *        /classes is in the classpath and we wish to examine files in /classes/org/apache then
326     *        the values of <i>parent</i> would be <i>org/apache</i>
327     * @param location a File object representing a directory
328     */
329    private void loadImplementationsInDirectory(final Test test, final String parent, final File location) {
330        final File[] files = location.listFiles();
331        if (files == null) {
332            return;
333        }
334
335        StringBuilder builder;
336        for (final File file : files) {
337            builder = new StringBuilder();
338            builder.append(parent).append("/").append(file.getName());
339            final String packageOrClass = parent == null ? file.getName() : builder.toString();
340
341            if (file.isDirectory()) {
342                loadImplementationsInDirectory(test, packageOrClass, file);
343            } else if (isTestApplicable(test, file.getName())) {
344                addIfMatching(test, packageOrClass);
345            }
346        }
347    }
348
349    private boolean isTestApplicable(final Test test, final String path) {
350        return test.doesMatchResource() || path.endsWith(".class") && test.doesMatchClass();
351    }
352
353    /**
354     * Finds matching classes within a jar files that contains a folder structure
355     * matching the package structure.  If the File is not a JarFile or does not exist a warning
356     * will be logged, but no error will be raised.
357     *
358     * @param test a Test used to filter the classes that are discovered
359     * @param parent the parent package under which classes must be in order to be considered
360     * @param jarFile the jar file to be examined for classes
361     */
362    private void loadImplementationsInJar(final Test test, final String parent, final File jarFile) {
363        @SuppressWarnings("resource")
364        JarInputStream jarStream = null;
365        try {
366            jarStream = new JarInputStream(new FileInputStream(jarFile));
367            loadImplementationsInJar(test, parent, jarFile.getPath(), jarStream);
368        } catch (final FileNotFoundException ex) {
369            LOGGER.error("Could not search jar file '" + jarFile + "' for classes matching criteria: " + test
370                    + " file not found");
371        } catch (final IOException ioe) {
372            LOGGER.error("Could not search jar file '" + jarFile + "' for classes matching criteria: " + test
373                    + " due to an IOException", ioe);
374        } finally {
375            close(jarStream, jarFile);
376        }
377    }
378
379    /**
380     * @param jarStream
381     * @param source
382     */
383    private void close(JarInputStream jarStream, final Object source) {
384        if (jarStream != null) {
385            try {
386                jarStream.close();
387            } catch (IOException e) {
388                LOGGER.error("Error closing JAR file stream for {}", source, e);
389            }
390        }
391    }
392
393    /**
394     * Finds matching classes within a jar files that contains a folder structure
395     * matching the package structure.  If the File is not a JarFile or does not exist a warning
396     * will be logged, but no error will be raised.
397     *
398     * @param test a Test used to filter the classes that are discovered
399     * @param parent the parent package under which classes must be in order to be considered
400     * @param stream The jar InputStream
401     */
402    private void loadImplementationsInJar(final Test test, final String parent, final String path,
403                                          final JarInputStream stream) {
404
405        try {
406            JarEntry entry;
407
408            while ((entry = stream.getNextJarEntry()) != null) {
409                final String name = entry.getName();
410                if (!entry.isDirectory() && name.startsWith(parent) && isTestApplicable(test, name)) {
411                    addIfMatching(test, name);
412                }
413            }
414        } catch (final IOException ioe) {
415            LOGGER.error("Could not search jar file '" + path + "' for classes matching criteria: " +
416                test + " due to an IOException", ioe);
417        }
418    }
419
420    /**
421     * Add the class designated by the fully qualified class name provided to the set of
422     * resolved classes if and only if it is approved by the Test supplied.
423     *
424     * @param test the test used to determine if the class matches
425     * @param fqn the fully qualified name of a class
426     */
427    protected void addIfMatching(final Test test, final String fqn) {
428        try {
429            final ClassLoader loader = getClassLoader();
430            if (test.doesMatchClass()) {
431                final String externalName = fqn.substring(0, fqn.indexOf('.')).replace('/', '.');
432                if (LOGGER.isDebugEnabled()) {
433                    LOGGER.debug("Checking to see if class " + externalName + " matches criteria [" + test + "]");
434                }
435
436                final Class<?> type = loader.loadClass(externalName);
437                if (test.matches(type)) {
438                    classMatches.add(type);
439                }
440            }
441            if (test.doesMatchResource()) {
442                URL url = loader.getResource(fqn);
443                if (url == null) {
444                    url = loader.getResource(fqn.substring(1));
445                }
446                if (url != null && test.matches(url.toURI())) {
447                    resourceMatches.add(url.toURI());
448                }
449            }
450        } catch (final Throwable t) {
451            LOGGER.warn("Could not examine class '" + fqn + "' due to a " +
452                t.getClass().getName() + " with message: " + t.getMessage());
453        }
454    }
455
456    /**
457     * A simple interface that specifies how to test classes to determine if they
458     * are to be included in the results produced by the ResolverUtil.
459     */
460    public interface Test {
461        /**
462         * Will be called repeatedly with candidate classes. Must return True if a class
463         * is to be included in the results, false otherwise.
464         * @param type The Class to match against.
465         * @return true if the Class matches.
466         */
467        boolean matches(Class<?> type);
468
469        /**
470         * Test for a resource.
471         * @param resource The URI to the resource.
472         * @return true if the resource matches.
473         */
474        boolean matches(URI resource);
475
476        boolean doesMatchClass();
477
478        boolean doesMatchResource();
479    }
480
481    /**
482     * Test against a Class.
483     */
484    public abstract static class ClassTest implements Test {
485        @Override
486        public boolean matches(final URI resource) {
487            throw new UnsupportedOperationException();
488        }
489
490        @Override
491        public boolean doesMatchClass() {
492            return true;
493        }
494
495        @Override
496        public boolean doesMatchResource() {
497            return false;
498        }
499    }
500
501    /**
502     * Test against a resource.
503     */
504    public abstract static class ResourceTest implements Test {
505        @Override
506        public boolean matches(final Class<?> cls) {
507            throw new UnsupportedOperationException();
508        }
509
510        @Override
511        public boolean doesMatchClass() {
512            return false;
513        }
514
515        @Override
516        public boolean doesMatchResource() {
517            return true;
518        }
519    }
520
521    /**
522     * A Test that checks to see if each class is assignable to the provided class. Note
523     * that this test will match the parent type itself if it is presented for matching.
524     */
525    public static class IsA extends ClassTest {
526        private final Class<?> parent;
527
528        /**
529         * Constructs an IsA test using the supplied Class as the parent class/interface.
530         * @param parentType The parent class to check for.
531         */
532        public IsA(final Class<?> parentType) { this.parent = parentType; }
533
534        /**
535         * Returns true if type is assignable to the parent type supplied in the constructor.
536         * @param type The Class to check.
537         * @return true if the Class matches.
538         */
539        @Override
540        public boolean matches(final Class<?> type) {
541            return type != null && parent.isAssignableFrom(type);
542        }
543
544        @Override
545        public String toString() {
546            return "is assignable to " + parent.getSimpleName();
547        }
548    }
549
550    /**
551     * A Test that checks to see if each class name ends with the provided suffix.
552     */
553    public static class NameEndsWith extends ClassTest {
554        private final String suffix;
555
556        /**
557         * Constructs a NameEndsWith test using the supplied suffix.
558         * @param suffix the String suffix to check for.
559         */
560        public NameEndsWith(final String suffix) { this.suffix = suffix; }
561
562        /**
563         * Returns true if type name ends with the suffix supplied in the constructor.
564         * @param type The Class to check.
565         * @return true if the Class matches.
566         */
567        @Override
568        public boolean matches(final Class<?> type) {
569            return type != null && type.getName().endsWith(suffix);
570        }
571
572        @Override
573        public String toString() {
574            return "ends with the suffix " + suffix;
575        }
576    }
577
578    /**
579     * A Test that checks to see if each class is annotated with a specific annotation. If it
580     * is, then the test returns true, otherwise false.
581     */
582    public static class AnnotatedWith extends ClassTest {
583        private final Class<? extends Annotation> annotation;
584
585        /**
586         * Constructs an AnnotatedWith test for the specified annotation type.
587         * @param annotation The annotation to check for.
588         */
589        public AnnotatedWith(final Class<? extends Annotation> annotation) {
590            this.annotation = annotation;
591        }
592
593        /**
594         * Returns true if the type is annotated with the class provided to the constructor.
595         * @param type the Class to match against.
596         * @return true if the Classes match.
597         */
598        @Override
599        public boolean matches(final Class<?> type) {
600            return type != null && type.isAnnotationPresent(annotation);
601        }
602
603        @Override
604        public String toString() {
605            return "annotated with @" + annotation.getSimpleName();
606        }
607    }
608
609    /**
610     * A Test that checks to see if the class name matches.
611     */
612    public static class NameIs extends ResourceTest {
613        private final String name;
614
615        public NameIs(final String name) { this.name = "/" + name; }
616
617        @Override
618        public boolean matches(final URI resource) {
619            return resource.getPath().endsWith(name);
620        }
621
622        @Override public String toString() {
623            return "named " + name;
624        }
625    }
626}