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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.core.config.plugins;
18  
19  import java.io.File;
20  import java.io.FileInputStream;
21  import java.io.FileNotFoundException;
22  import java.io.IOException;
23  import java.io.UnsupportedEncodingException;
24  import java.lang.annotation.Annotation;
25  import java.net.URI;
26  import java.net.URL;
27  import java.net.URLDecoder;
28  import java.util.Arrays;
29  import java.util.Collection;
30  import java.util.Enumeration;
31  import java.util.HashSet;
32  import java.util.List;
33  import java.util.Set;
34  import java.util.jar.JarEntry;
35  import java.util.jar.JarInputStream;
36  
37  import org.apache.logging.log4j.Logger;
38  import org.apache.logging.log4j.core.helpers.Charsets;
39  import org.apache.logging.log4j.core.helpers.Loader;
40  import org.apache.logging.log4j.status.StatusLogger;
41  import org.osgi.framework.FrameworkUtil;
42  import org.osgi.framework.wiring.BundleWiring;
43  
44  /**
45   * <p>ResolverUtil is used to locate classes that are available in the/a class path and meet
46   * arbitrary conditions. The two most common conditions are that a class implements/extends
47   * another class, or that is it annotated with a specific annotation. However, through the use
48   * of the {@link Test} class it is possible to search using arbitrary conditions.</p>
49   *
50   * <p>A ClassLoader is used to locate all locations (directories and jar files) in the class
51   * path that contain classes within certain packages, and then to load those classes and
52   * check them. By default the ClassLoader returned by
53   *  {@code Thread.currentThread().getContextClassLoader()} is used, but this can be overridden
54   * by calling {@link #setClassLoader(ClassLoader)} prior to invoking any of the {@code find()}
55   * methods.</p>
56   *
57   * <p>General searches are initiated by calling the
58   * {@link #find(ResolverUtil.Test, String...)} method and supplying
59   * a package name and a Test instance. This will cause the named package <b>and all sub-packages</b>
60   * to be scanned for classes that meet the test. There are also utility methods for the common
61   * use cases of scanning multiple packages for extensions of particular classes, or classes
62   * annotated with a specific annotation.</p>
63   *
64   * <p>The standard usage pattern for the ResolverUtil class is as follows:</p>
65   *
66   *<pre>
67   *ResolverUtil&lt;ActionBean&gt; resolver = new ResolverUtil&lt;ActionBean&gt;();
68   *resolver.findImplementation(ActionBean.class, pkg1, pkg2);
69   *resolver.find(new CustomTest(), pkg1);
70   *resolver.find(new CustomTest(), pkg2);
71   *Collection&lt;ActionBean&gt; beans = resolver.getClasses();
72   *</pre>
73   *
74   * <p>This class was copied and modified from Stripes - http://stripes.mc4j.org/confluence/display/stripes/Home
75   * </p>
76   */
77  public class ResolverUtil {
78      /** An instance of Log to use for logging in this class. */
79      private static final Logger LOGGER = StatusLogger.getLogger();
80  
81      private static final String VFSZIP = "vfszip";
82  
83      private static final String BUNDLE_RESOURCE = "bundleresource";
84  
85      /** The set of matches being accumulated. */
86      private final Set<Class<?>> classMatches = new HashSet<Class<?>>();
87  
88      /** The set of matches being accumulated. */
89      private final Set<URI> resourceMatches = new HashSet<URI>();
90  
91      /**
92       * The ClassLoader to use when looking for classes. If null then the ClassLoader returned
93       * by Thread.currentThread().getContextClassLoader() will be used.
94       */
95      private ClassLoader classloader;
96  
97      /**
98       * Provides access to the classes discovered so far. If no calls have been made to
99       * 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 }