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 */ 017 package org.apache.logging.log4j.core.config.plugins; 018 019 import org.apache.logging.log4j.Logger; 020 import org.apache.logging.log4j.core.helpers.Loader; 021 import org.apache.logging.log4j.status.StatusLogger; 022 import org.osgi.framework.FrameworkUtil; 023 import org.osgi.framework.wiring.BundleWiring; 024 025 import java.io.File; 026 import java.io.FileInputStream; 027 import java.io.FileNotFoundException; 028 import java.io.IOException; 029 import java.lang.annotation.Annotation; 030 import java.net.URI; 031 import java.net.URL; 032 import java.net.URLDecoder; 033 import java.util.Collection; 034 import java.util.Enumeration; 035 import java.util.HashSet; 036 import java.util.Set; 037 import java.util.jar.JarEntry; 038 import java.util.jar.JarInputStream; 039 040 /** 041 * <p>ResolverUtil is used to locate classes that are available in the/a class path and meet 042 * arbitrary conditions. The two most common conditions are that a class implements/extends 043 * another class, or that is it annotated with a specific annotation. However, through the use 044 * of the {@link Test} class it is possible to search using arbitrary conditions.</p> 045 * 046 * <p>A ClassLoader is used to locate all locations (directories and jar files) in the class 047 * path that contain classes within certain packages, and then to load those classes and 048 * check them. By default the ClassLoader returned by 049 * {@code Thread.currentThread().getContextClassLoader()} is used, but this can be overridden 050 * by calling {@link #setClassLoader(ClassLoader)} prior to invoking any of the {@code find()} 051 * methods.</p> 052 * 053 * <p>General searches are initiated by calling the 054 * {@link #find(ResolverUtil.Test, String...)} method and supplying 055 * a package name and a Test instance. This will cause the named package <b>and all sub-packages</b> 056 * to be scanned for classes that meet the test. There are also utility methods for the common 057 * use cases of scanning multiple packages for extensions of particular classes, or classes 058 * annotated with a specific annotation.</p> 059 * 060 * <p>The standard usage pattern for the ResolverUtil class is as follows:</p> 061 * 062 *<pre> 063 *ResolverUtil<ActionBean> resolver = new ResolverUtil<ActionBean>(); 064 *resolver.findImplementation(ActionBean.class, pkg1, pkg2); 065 *resolver.find(new CustomTest(), pkg1); 066 *resolver.find(new CustomTest(), pkg2); 067 *Collection<ActionBean> beans = resolver.getClasses(); 068 *</pre> 069 * 070 * <p>This class was copied from Stripes - http://stripes.mc4j.org/confluence/display/stripes/Home 071 * </p> 072 * 073 * @author Tim Fennell 074 * @param <T> The type of the Class that can be returned. 075 */ 076 public class ResolverUtil<T> { 077 /** An instance of Log to use for logging in this class. */ 078 private static final Logger LOG = StatusLogger.getLogger(); 079 080 private static final String VFSZIP = "vfszip"; 081 082 private static final String BUNDLE_RESOURCE = "bundleresource"; 083 084 /** The set of matches being accumulated. */ 085 private Set<Class<? extends T>> classMatches = new HashSet<Class<?extends T>>(); 086 087 /** The set of matches being accumulated. */ 088 private Set<URI> resourceMatches = new HashSet<URI>(); 089 090 /** 091 * The ClassLoader to use when looking for classes. If null then the ClassLoader returned 092 * by Thread.currentThread().getContextClassLoader() will be used. 093 */ 094 private ClassLoader classloader; 095 096 /** 097 * Provides access to the classes discovered so far. If no calls have been made to 098 * any of the {@code find()} methods, this set will be empty. 099 * 100 * @return the set of classes that have been discovered. 101 */ 102 public Set<Class<? extends T>> 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(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(Class parent, String... packageNames) { 143 if (packageNames == null) { 144 return; 145 } 146 147 Test test = new IsA(parent); 148 for (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(String suffix, String... packageNames) { 161 if (packageNames == null) { 162 return; 163 } 164 165 Test test = new NameEndsWith(suffix); 166 for (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(Class<? extends Annotation> annotation, String... packageNames) { 179 if (packageNames == null) { 180 return; 181 } 182 183 Test test = new AnnotatedWith(annotation); 184 for (String pkg : packageNames) { 185 findInPackage(test, pkg); 186 } 187 } 188 189 public void findNamedResource(String name, String... pathNames) { 190 if (pathNames == null) { 191 return; 192 } 193 194 Test test = new NameIs(name); 195 for (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(Test test, String... packageNames) { 208 if (packageNames == null) { 209 return; 210 } 211 212 for (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(Test test, String packageName) { 228 packageName = packageName.replace('.', '/'); 229 ClassLoader loader = getClassLoader(); 230 Enumeration<URL> urls; 231 232 try { 233 urls = loader.getResources(packageName); 234 } catch (IOException ioe) { 235 LOG.warn("Could not read package: " + packageName, ioe); 236 return; 237 } 238 239 while (urls.hasMoreElements()) { 240 try { 241 URL url = urls.nextElement(); 242 String urlPath = url.getFile(); 243 urlPath = URLDecoder.decode(urlPath, "UTF-8"); 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 String path = urlPath.substring(0, urlPath.length() - packageName.length() - 2); 259 URL newURL = new URL(url.getProtocol(), url.getHost(), path); 260 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 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 (IOException ioe) { 273 LOG.warn("could not read entries", ioe); 274 } 275 } 276 } 277 278 private void loadImplementationsInBundle(Test test, String packageName) { 279 BundleWiring wiring = (BundleWiring)FrameworkUtil.getBundle(ResolverUtil.class).adapt(BundleWiring.class); 280 Collection<String> list = wiring.listResources(packageName, "*.class", BundleWiring.LISTRESOURCES_RECURSE); 281 for (String name : list) { 282 addIfMatching(test, name); 283 } 284 } 285 286 287 /** 288 * Finds matches in a physical directory on a filesystem. Examines all 289 * files within a directory - if the File object is not a directory, and ends with <i>.class</i> 290 * the file is loaded and tested to see if it is acceptable according to the Test. Operates 291 * recursively to find classes within a folder structure matching the package structure. 292 * 293 * @param test a Test used to filter the classes that are discovered 294 * @param parent the package name up to this directory in the package hierarchy. E.g. if 295 * /classes is in the classpath and we wish to examine files in /classes/org/apache then 296 * the values of <i>parent</i> would be <i>org/apache</i> 297 * @param location a File object representing a directory 298 */ 299 private void loadImplementationsInDirectory(Test test, String parent, File location) { 300 File[] files = location.listFiles(); 301 StringBuilder builder; 302 303 for (File file : files) { 304 builder = new StringBuilder(); 305 builder.append(parent).append("/").append(file.getName()); 306 String packageOrClass = parent == null ? file.getName() : builder.toString(); 307 308 if (file.isDirectory()) { 309 loadImplementationsInDirectory(test, packageOrClass, file); 310 } else if (isTestApplicable(test, file.getName())) { 311 addIfMatching(test, packageOrClass); 312 } 313 } 314 } 315 316 private boolean isTestApplicable(Test test, String path) { 317 return test.doesMatchResource() || path.endsWith(".class") && test.doesMatchClass(); 318 } 319 320 /** 321 * Finds matching classes within a jar files that contains a folder structure 322 * matching the package structure. If the File is not a JarFile or does not exist a warning 323 * will be logged, but no error will be raised. 324 * 325 * @param test a Test used to filter the classes that are discovered 326 * @param parent the parent package under which classes must be in order to be considered 327 * @param jarfile the jar file to be examined for classes 328 */ 329 private void loadImplementationsInJar(Test test, String parent, File jarfile) { 330 JarInputStream jarStream; 331 try { 332 jarStream = new JarInputStream(new FileInputStream(jarfile)); 333 loadImplementationsInJar(test, parent, jarfile.getPath(), jarStream); 334 } catch (FileNotFoundException ex) { 335 LOG.error("Could not search jar file '" + jarfile + "' for classes matching criteria: " + 336 test + " file not found"); 337 } catch (IOException ioe) { 338 LOG.error("Could not search jar file '" + jarfile + "' for classes matching criteria: " + 339 test + " due to an IOException", ioe); 340 } 341 } 342 343 /** 344 * Finds matching classes within a jar files that contains a folder structure 345 * matching the package structure. If the File is not a JarFile or does not exist a warning 346 * will be logged, but no error will be raised. 347 * 348 * @param test a Test used to filter the classes that are discovered 349 * @param parent the parent package under which classes must be in order to be considered 350 * @param stream The jar InputStream 351 */ 352 private void loadImplementationsInJar(Test test, String parent, String path, JarInputStream stream) { 353 354 try { 355 JarEntry entry; 356 357 while ((entry = stream.getNextJarEntry()) != null) { 358 String name = entry.getName(); 359 if (!entry.isDirectory() && name.startsWith(parent) && isTestApplicable(test, name)) { 360 addIfMatching(test, name); 361 } 362 } 363 } catch (IOException ioe) { 364 LOG.error("Could not search jar file '" + path + "' for classes matching criteria: " + 365 test + " due to an IOException", ioe); 366 } 367 } 368 369 /** 370 * Add the class designated by the fully qualified class name provided to the set of 371 * resolved classes if and only if it is approved by the Test supplied. 372 * 373 * @param test the test used to determine if the class matches 374 * @param fqn the fully qualified name of a class 375 */ 376 protected void addIfMatching(Test test, String fqn) { 377 try { 378 ClassLoader loader = getClassLoader(); 379 if (test.doesMatchClass()) { 380 String externalName = fqn.substring(0, fqn.indexOf('.')).replace('/', '.'); 381 if (LOG.isDebugEnabled()) { 382 LOG.debug("Checking to see if class " + externalName + " matches criteria [" + test + "]"); 383 } 384 385 Class type = loader.loadClass(externalName); 386 if (test.matches(type)) { 387 classMatches.add(type); 388 } 389 } 390 if (test.doesMatchResource()) { 391 URL url = loader.getResource(fqn); 392 if (url == null) { 393 url = loader.getResource(fqn.substring(1)); 394 } 395 if (url != null && test.matches(url.toURI())) { 396 resourceMatches.add(url.toURI()); 397 } 398 } 399 } catch (Throwable t) { 400 LOG.warn("Could not examine class '" + fqn + "' due to a " + 401 t.getClass().getName() + " with message: " + t.getMessage()); 402 } 403 } 404 405 /** 406 * A simple interface that specifies how to test classes to determine if they 407 * are to be included in the results produced by the ResolverUtil. 408 */ 409 public interface Test { 410 /** 411 * Will be called repeatedly with candidate classes. Must return True if a class 412 * is to be included in the results, false otherwise. 413 * @param type The Class to match against. 414 * @return true if the Class matches. 415 */ 416 boolean matches(Class type); 417 418 /** 419 * Test for a resource. 420 * @param resource The URI to the resource. 421 * @return true if the resource matches. 422 */ 423 boolean matches(URI resource); 424 425 boolean doesMatchClass(); 426 boolean doesMatchResource(); 427 } 428 429 /** 430 * Test against a Class. 431 */ 432 public abstract static class ClassTest implements Test { 433 public boolean matches(URI resource) { 434 throw new UnsupportedOperationException(); 435 } 436 437 public boolean doesMatchClass() { 438 return true; 439 } 440 public boolean doesMatchResource() { 441 return false; 442 } 443 } 444 445 /** 446 * Test against a resource. 447 */ 448 public abstract static class ResourceTest implements Test { 449 public boolean matches(Class cls) { 450 throw new UnsupportedOperationException(); 451 } 452 453 public boolean doesMatchClass() { 454 return false; 455 } 456 public boolean doesMatchResource() { 457 return true; 458 } 459 } 460 461 /** 462 * A Test that checks to see if each class is assignable to the provided class. Note 463 * that this test will match the parent type itself if it is presented for matching. 464 */ 465 public static class IsA extends ClassTest { 466 private final Class parent; 467 468 /** 469 * Constructs an IsA test using the supplied Class as the parent class/interface. 470 * @param parentType The parent class to check for. 471 */ 472 public IsA(Class parentType) { this.parent = parentType; } 473 474 /** 475 * Returns true if type is assignable to the parent type supplied in the constructor. 476 * @param type The Class to check. 477 * @return true if the Class matches. 478 */ 479 public boolean matches(Class type) { 480 return type != null && parent.isAssignableFrom(type); 481 } 482 483 @Override 484 public String toString() { 485 return "is assignable to " + parent.getSimpleName(); 486 } 487 } 488 489 /** 490 * A Test that checks to see if each class name ends with the provided suffix. 491 */ 492 public static class NameEndsWith extends ClassTest { 493 private final String suffix; 494 495 /** 496 * Constructs a NameEndsWith test using the supplied suffix. 497 * @param suffix the String suffix to check for. 498 */ 499 public NameEndsWith(String suffix) { this.suffix = suffix; } 500 501 /** 502 * Returns true if type name ends with the suffix supplied in the constructor. 503 * @param type The Class to check. 504 * @return true if the Class matches. 505 */ 506 public boolean matches(Class type) { 507 return type != null && type.getName().endsWith(suffix); 508 } 509 510 @Override 511 public String toString() { 512 return "ends with the suffix " + suffix; 513 } 514 } 515 516 /** 517 * A Test that checks to see if each class is annotated with a specific annotation. If it 518 * is, then the test returns true, otherwise false. 519 */ 520 public static class AnnotatedWith extends ClassTest { 521 private final Class<? extends Annotation> annotation; 522 523 /** 524 * Constructs an AnnotatedWith test for the specified annotation type. 525 * @param annotation The annotation to check for. 526 */ 527 public AnnotatedWith(Class<? extends Annotation> annotation) { 528 this.annotation = annotation; 529 } 530 531 /** 532 * Returns true if the type is annotated with the class provided to the constructor. 533 * @param type the Class to match against. 534 * @return true if the Classes match. 535 */ 536 public boolean matches(Class type) { 537 return type != null && type.isAnnotationPresent(annotation); 538 } 539 540 @Override 541 public String toString() { 542 return "annotated with @" + annotation.getSimpleName(); 543 } 544 } 545 546 /** 547 * A Test that checks to see if the class name matches. 548 */ 549 public static class NameIs extends ResourceTest { 550 private final String name; 551 552 public NameIs(String name) { this.name = "/" + name; } 553 554 public boolean matches(URI resource) { 555 return resource.getPath().endsWith(name); 556 } 557 558 @Override public String toString() { 559 return "named " + name; 560 } 561 } 562 }