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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.lang.annotation.Annotation;
24  import java.net.URI;
25  import java.net.URL;
26  import java.net.URLDecoder;
27  import java.util.Collection;
28  import java.util.Enumeration;
29  import java.util.HashSet;
30  import java.util.Set;
31  import java.util.jar.JarEntry;
32  import java.util.jar.JarInputStream;
33  
34  import org.apache.logging.log4j.Logger;
35  import org.apache.logging.log4j.core.helpers.Charsets;
36  import org.apache.logging.log4j.core.helpers.Loader;
37  import org.apache.logging.log4j.status.StatusLogger;
38  import org.osgi.framework.FrameworkUtil;
39  import org.osgi.framework.wiring.BundleWiring;
40  
41  /**
42   * <p>ResolverUtil is used to locate classes that are available in the/a class path and meet
43   * arbitrary conditions. The two most common conditions are that a class implements/extends
44   * another class, or that is it annotated with a specific annotation. However, through the use
45   * of the {@link Test} class it is possible to search using arbitrary conditions.</p>
46   *
47   * <p>A ClassLoader is used to locate all locations (directories and jar files) in the class
48   * path that contain classes within certain packages, and then to load those classes and
49   * check them. By default the ClassLoader returned by
50   *  {@code Thread.currentThread().getContextClassLoader()} is used, but this can be overridden
51   * by calling {@link #setClassLoader(ClassLoader)} prior to invoking any of the {@code find()}
52   * methods.</p>
53   *
54   * <p>General searches are initiated by calling the
55   * {@link #find(ResolverUtil.Test, String...)} method and supplying
56   * a package name and a Test instance. This will cause the named package <b>and all sub-packages</b>
57   * to be scanned for classes that meet the test. There are also utility methods for the common
58   * use cases of scanning multiple packages for extensions of particular classes, or classes
59   * annotated with a specific annotation.</p>
60   *
61   * <p>The standard usage pattern for the ResolverUtil class is as follows:</p>
62   *
63   *<pre>
64   *ResolverUtil&lt;ActionBean&gt; resolver = new ResolverUtil&lt;ActionBean&gt;();
65   *resolver.findImplementation(ActionBean.class, pkg1, pkg2);
66   *resolver.find(new CustomTest(), pkg1);
67   *resolver.find(new CustomTest(), pkg2);
68   *Collection&lt;ActionBean&gt; beans = resolver.getClasses();
69   *</pre>
70   *
71   * <p>This class was copied from Stripes - http://stripes.mc4j.org/confluence/display/stripes/Home
72   * </p>
73   *
74   * @author Tim Fennell
75   */
76  public class ResolverUtil {
77      /** An instance of Log to use for logging in this class. */
78      private static final Logger LOG = StatusLogger.getLogger();
79  
80      private static final String VFSZIP = "vfszip";
81  
82      private static final String BUNDLE_RESOURCE = "bundleresource";
83  
84      /** The set of matches being accumulated. */
85      private final Set<Class<?>> classMatches = new HashSet<Class<?>>();
86  
87      /** The set of matches being accumulated. */
88      private final Set<URI> resourceMatches = new HashSet<URI>();
89  
90      /**
91       * The ClassLoader to use when looking for classes. If null then the ClassLoader returned
92       * by Thread.currentThread().getContextClassLoader() will be used.
93       */
94      private ClassLoader classloader;
95  
96      /**
97       * Provides access to the classes discovered so far. If no calls have been made to
98       * any of the {@code find()} methods, this set will be empty.
99       *
100      * @return the set of classes that have been discovered.
101      */
102     public Set<Class<?>> getClasses() {
103         return classMatches;
104     }
105 
106     /**
107      * Returns the matching resources.
108      * @return A Set of URIs that match the criteria.
109      */
110     public Set<URI> getResources() {
111         return resourceMatches;
112     }
113 
114 
115     /**
116      * Returns the classloader that will be used for scanning for classes. If no explicit
117      * ClassLoader has been set by the calling, the context class loader will be used.
118      *
119      * @return the ClassLoader that will be used to scan for classes
120      */
121     public ClassLoader getClassLoader() {
122         return classloader != null ? classloader : (classloader = Loader.getClassLoader(ResolverUtil.class, null));
123     }
124 
125     /**
126      * Sets an explicit ClassLoader that should be used when scanning for classes. If none
127      * is set then the context classloader will be used.
128      *
129      * @param classloader a ClassLoader to use when scanning for classes
130      */
131     public void setClassLoader(final ClassLoader classloader) { this.classloader = classloader; }
132 
133     /**
134      * Attempts to discover classes that are assignable to the type provided. In the case
135      * that an interface is provided this method will collect implementations. In the case
136      * of a non-interface class, subclasses will be collected.  Accumulated classes can be
137      * accessed by calling {@link #getClasses()}.
138      *
139      * @param parent the class of interface to find subclasses or implementations of
140      * @param packageNames one or more package names to scan (including subpackages) for classes
141      */
142     public void findImplementations(final Class<?> parent, final String... packageNames) {
143         if (packageNames == null) {
144             return;
145         }
146 
147         final Test test = new IsA(parent);
148         for (final String pkg : packageNames) {
149             findInPackage(test, pkg);
150         }
151     }
152 
153     /**
154      * Attempts to discover classes who's name ends with the provided suffix. Accumulated classes can be
155      * accessed by calling {@link #getClasses()}.
156      *
157      * @param suffix The class name suffix to match
158      * @param packageNames one or more package names to scan (including subpackages) for classes
159      */
160     public void findSuffix(final String suffix, final String... packageNames) {
161         if (packageNames == null) {
162             return;
163         }
164 
165         final Test test = new NameEndsWith(suffix);
166         for (final String pkg : packageNames) {
167             findInPackage(test, pkg);
168         }
169     }
170 
171     /**
172      * Attempts to discover classes that are annotated with to the annotation. Accumulated
173      * classes can be accessed by calling {@link #getClasses()}.
174      *
175      * @param annotation the annotation that should be present on matching classes
176      * @param packageNames one or more package names to scan (including subpackages) for classes
177      */
178     public void findAnnotated(final Class<? extends Annotation> annotation, final String... packageNames) {
179         if (packageNames == null) {
180             return;
181         }
182 
183         final Test test = new AnnotatedWith(annotation);
184         for (final String pkg : packageNames) {
185             findInPackage(test, pkg);
186         }
187     }
188 
189     public void findNamedResource(final String name, final String... pathNames) {
190         if (pathNames == null) {
191             return;
192         }
193 
194         final Test test = new NameIs(name);
195         for (final String pkg : pathNames) {
196             findInPackage(test, pkg);
197         }
198     }
199 
200     /**
201      * Attempts to discover classes that pass the test. Accumulated
202      * classes can be accessed by calling {@link #getClasses()}.
203      *
204      * @param test the test to determine matching classes
205      * @param packageNames one or more package names to scan (including subpackages) for classes
206      */
207     public void find(final Test test, final String... packageNames) {
208         if (packageNames == null) {
209             return;
210         }
211 
212         for (final String pkg : packageNames) {
213             findInPackage(test, pkg);
214         }
215     }
216 
217     /**
218      * Scans for classes starting at the package provided and descending into subpackages.
219      * Each class is offered up to the Test as it is discovered, and if the Test returns
220      * true the class is retained.  Accumulated classes can be fetched by calling
221      * {@link #getClasses()}.
222      *
223      * @param test an instance of {@link Test} that will be used to filter classes
224      * @param packageName the name of the package from which to start scanning for
225      *        classes, e.g. {@code net.sourceforge.stripes}
226      */
227     public void findInPackage(final Test test, String packageName) {
228         packageName = packageName.replace('.', '/');
229         final ClassLoader loader = getClassLoader();
230         Enumeration<URL> urls;
231 
232         try {
233             urls = loader.getResources(packageName);
234         } catch (final IOException ioe) {
235             LOG.warn("Could not read package: " + packageName, ioe);
236             return;
237         }
238 
239         while (urls.hasMoreElements()) {
240             try {
241                 final URL url = urls.nextElement();
242                 String urlPath = url.getFile();
243                 urlPath = URLDecoder.decode(urlPath, Charsets.UTF_8.name());
244 
245                 // If it's a file in a directory, trim the stupid file: spec
246                 if (urlPath.startsWith("file:")) {
247                     urlPath = urlPath.substring(5);
248                 }
249 
250                 // Else it's in a JAR, grab the path to the jar
251                 if (urlPath.indexOf('!') > 0) {
252                     urlPath = urlPath.substring(0, urlPath.indexOf('!'));
253                 }
254 
255                 LOG.info("Scanning for classes in [" + urlPath + "] matching criteria: " + test);
256                 // Check for a jar in a war in JBoss
257                 if (VFSZIP.equals(url.getProtocol())) {
258                     final String path = urlPath.substring(0, urlPath.length() - packageName.length() - 2);
259                     final URL newURL = new URL(url.getProtocol(), url.getHost(), path);
260                     final JarInputStream stream = new JarInputStream(newURL.openStream());
261                     loadImplementationsInJar(test, packageName, path, stream);
262                 } else if (BUNDLE_RESOURCE.equals(url.getProtocol())) {
263                     loadImplementationsInBundle(test, packageName);
264                 } else {
265                     final File file = new File(urlPath);
266                     if (file.isDirectory()) {
267                         loadImplementationsInDirectory(test, packageName, file);
268                     } else {
269                         loadImplementationsInJar(test, packageName, file);
270                     }
271                 }
272             } catch (final IOException ioe) {
273                 LOG.warn("could not read entries", ioe);
274             }
275         }
276     }
277 
278     private void loadImplementationsInBundle(final Test test, final String packageName) {
279         //Do not remove the cast on the next line as removing it will cause a compile error on Java 7.
280         final BundleWiring wiring = (BundleWiring) FrameworkUtil.getBundle(
281                 ResolverUtil.class).adapt(BundleWiring.class);
282         final Collection<String> list = wiring.listResources(packageName, "*.class",
283             BundleWiring.LISTRESOURCES_RECURSE);
284         for (final String name : list) {
285             addIfMatching(test, name);
286         }
287     }
288 
289 
290     /**
291      * Finds matches in a physical directory on a filesystem.  Examines all
292      * files within a directory - if the File object is not a directory, and ends with <i>.class</i>
293      * the file is loaded and tested to see if it is acceptable according to the Test.  Operates
294      * recursively to find classes within a folder structure matching the package structure.
295      *
296      * @param test a Test used to filter the classes that are discovered
297      * @param parent the package name up to this directory in the package hierarchy.  E.g. if
298      *        /classes is in the classpath and we wish to examine files in /classes/org/apache then
299      *        the values of <i>parent</i> would be <i>org/apache</i>
300      * @param location a File object representing a directory
301      */
302     private void loadImplementationsInDirectory(final Test test, final String parent, final File location) {
303         final File[] files = location.listFiles();
304         if(files == null)
305             return;
306 
307         StringBuilder builder;
308         for (final File file : files) {
309             builder = new StringBuilder();
310             builder.append(parent).append("/").append(file.getName());
311             final String packageOrClass = parent == null ? file.getName() : builder.toString();
312 
313             if (file.isDirectory()) {
314                 loadImplementationsInDirectory(test, packageOrClass, file);
315             } else if (isTestApplicable(test, file.getName())) {
316                 addIfMatching(test, packageOrClass);
317             }
318         }
319     }
320 
321     private boolean isTestApplicable(final Test test, final String path) {
322         return test.doesMatchResource() || path.endsWith(".class") && test.doesMatchClass();
323     }
324 
325     /**
326      * Finds matching classes within a jar files that contains a folder structure
327      * matching the package structure.  If the File is not a JarFile or does not exist a warning
328      * will be logged, but no error will be raised.
329      *
330      * @param test a Test used to filter the classes that are discovered
331      * @param parent the parent package under which classes must be in order to be considered
332      * @param jarfile the jar file to be examined for classes
333      */
334     private void loadImplementationsInJar(final Test test, final String parent, final File jarfile) {
335         JarInputStream jarStream;
336         try {
337             jarStream = new JarInputStream(new FileInputStream(jarfile));
338             loadImplementationsInJar(test, parent, jarfile.getPath(), jarStream);
339         } catch (final FileNotFoundException ex) {
340             LOG.error("Could not search jar file '" + jarfile + "' for classes matching criteria: " +
341                 test + " file not found");
342         } catch (final IOException ioe) {
343             LOG.error("Could not search jar file '" + jarfile + "' for classes matching criteria: " +
344                 test + " due to an IOException", ioe);
345         }
346     }
347 
348     /**
349      * Finds matching classes within a jar files that contains a folder structure
350      * matching the package structure.  If the File is not a JarFile or does not exist a warning
351      * will be logged, but no error will be raised.
352      *
353      * @param test a Test used to filter the classes that are discovered
354      * @param parent the parent package under which classes must be in order to be considered
355      * @param stream The jar InputStream
356      */
357     private void loadImplementationsInJar(final Test test, final String parent, final String path,
358                                           final JarInputStream stream) {
359 
360         try {
361             JarEntry entry;
362 
363             while ((entry = stream.getNextJarEntry()) != null) {
364                 final String name = entry.getName();
365                 if (!entry.isDirectory() && name.startsWith(parent) && isTestApplicable(test, name)) {
366                     addIfMatching(test, name);
367                 }
368             }
369         } catch (final IOException ioe) {
370             LOG.error("Could not search jar file '" + path + "' for classes matching criteria: " +
371                 test + " due to an IOException", ioe);
372         }
373     }
374 
375     /**
376      * Add the class designated by the fully qualified class name provided to the set of
377      * resolved classes if and only if it is approved by the Test supplied.
378      *
379      * @param test the test used to determine if the class matches
380      * @param fqn the fully qualified name of a class
381      */
382     protected void addIfMatching(final Test test, final String fqn) {
383         try {
384             final ClassLoader loader = getClassLoader();
385             if (test.doesMatchClass()) {
386                 final String externalName = fqn.substring(0, fqn.indexOf('.')).replace('/', '.');
387                 if (LOG.isDebugEnabled()) {
388                     LOG.debug("Checking to see if class " + externalName + " matches criteria [" + test + "]");
389                 }
390 
391                 final Class<?> type = loader.loadClass(externalName);
392                 if (test.matches(type)) {
393                     classMatches.add(type);
394                 }
395             }
396             if (test.doesMatchResource()) {
397                 URL url = loader.getResource(fqn);
398                 if (url == null) {
399                     url = loader.getResource(fqn.substring(1));
400                 }
401                 if (url != null && test.matches(url.toURI())) {
402                     resourceMatches.add(url.toURI());
403                 }
404             }
405         } catch (final Throwable t) {
406             LOG.warn("Could not examine class '" + fqn + "' due to a " +
407                 t.getClass().getName() + " with message: " + t.getMessage());
408         }
409     }
410 
411     /**
412      * A simple interface that specifies how to test classes to determine if they
413      * are to be included in the results produced by the ResolverUtil.
414      */
415     public interface Test {
416         /**
417          * Will be called repeatedly with candidate classes. Must return True if a class
418          * is to be included in the results, false otherwise.
419          * @param type The Class to match against.
420          * @return true if the Class matches.
421          */
422         boolean matches(Class<?> type);
423 
424         /**
425          * Test for a resource.
426          * @param resource The URI to the resource.
427          * @return true if the resource matches.
428          */
429         boolean matches(URI resource);
430 
431         boolean doesMatchClass();
432 
433         boolean doesMatchResource();
434     }
435 
436     /**
437      * Test against a Class.
438      */
439     public abstract static class ClassTest implements Test {
440         @Override
441         public boolean matches(final URI resource) {
442             throw new UnsupportedOperationException();
443         }
444 
445         @Override
446         public boolean doesMatchClass() {
447             return true;
448         }
449 
450         @Override
451         public boolean doesMatchResource() {
452             return false;
453         }
454     }
455 
456     /**
457      * Test against a resource.
458      */
459     public abstract static class ResourceTest implements Test {
460         @Override
461         public boolean matches(final Class<?> cls) {
462             throw new UnsupportedOperationException();
463         }
464 
465         @Override
466         public boolean doesMatchClass() {
467             return false;
468         }
469 
470         @Override
471         public boolean doesMatchResource() {
472             return true;
473         }
474     }
475 
476     /**
477      * A Test that checks to see if each class is assignable to the provided class. Note
478      * that this test will match the parent type itself if it is presented for matching.
479      */
480     public static class IsA extends ClassTest {
481         private final Class<?> parent;
482 
483         /**
484          * Constructs an IsA test using the supplied Class as the parent class/interface.
485          * @param parentType The parent class to check for.
486          */
487         public IsA(final Class<?> parentType) { this.parent = parentType; }
488 
489         /**
490          * Returns true if type is assignable to the parent type supplied in the constructor.
491          * @param type The Class to check.
492          * @return true if the Class matches.
493          */
494         @Override
495         public boolean matches(final Class<?> type) {
496             return type != null && parent.isAssignableFrom(type);
497         }
498 
499         @Override
500         public String toString() {
501             return "is assignable to " + parent.getSimpleName();
502         }
503     }
504 
505     /**
506      * A Test that checks to see if each class name ends with the provided suffix.
507      */
508     public static class NameEndsWith extends ClassTest {
509         private final String suffix;
510 
511         /**
512          * Constructs a NameEndsWith test using the supplied suffix.
513          * @param suffix the String suffix to check for.
514          */
515         public NameEndsWith(final String suffix) { this.suffix = suffix; }
516 
517         /**
518          * Returns true if type name ends with the suffix supplied in the constructor.
519          * @param type The Class to check.
520          * @return true if the Class matches.
521          */
522         @Override
523         public boolean matches(final Class<?> type) {
524             return type != null && type.getName().endsWith(suffix);
525         }
526 
527         @Override
528         public String toString() {
529             return "ends with the suffix " + suffix;
530         }
531     }
532 
533     /**
534      * A Test that checks to see if each class is annotated with a specific annotation. If it
535      * is, then the test returns true, otherwise false.
536      */
537     public static class AnnotatedWith extends ClassTest {
538         private final Class<? extends Annotation> annotation;
539 
540         /**
541          * Constructs an AnnotatedWith test for the specified annotation type.
542          * @param annotation The annotation to check for.
543          */
544         public AnnotatedWith(final Class<? extends Annotation> annotation) {
545             this.annotation = annotation;
546         }
547 
548         /**
549          * Returns true if the type is annotated with the class provided to the constructor.
550          * @param type the Class to match against.
551          * @return true if the Classes match.
552          */
553         @Override
554         public boolean matches(final Class<?> type) {
555             return type != null && type.isAnnotationPresent(annotation);
556         }
557 
558         @Override
559         public String toString() {
560             return "annotated with @" + annotation.getSimpleName();
561         }
562     }
563 
564     /**
565      * A Test that checks to see if the class name matches.
566      */
567     public static class NameIs extends ResourceTest {
568         private final String name;
569 
570         public NameIs(final String name) { this.name = "/" + name; }
571 
572         @Override
573         public boolean matches(final URI resource) {
574             return resource.getPath().endsWith(name);
575         }
576 
577         @Override public String toString() {
578             return "named " + name;
579         }
580     }
581 }