Class ClassPath

corpus/java/training/guava/reflect/ClassPath.java:63–507

Scans the source of a ClassLoader and finds all loadable classes and resources. Warning: Currently only URLClassLoader and only file:// urls are supported. @author Ben Yu @since 14.0

 * @since 14.0
 */
@Beta
public final class ClassPath {
  private static final Logger logger = Logger.getLogger(ClassPath.class.getName());

  private static final Predicate<ClassInfo> IS_TOP_LEVEL =
      new Predicate<ClassInfo>() {
        @Override
        public boolean apply(ClassInfo info) {
          return info.className.indexOf('$') == -1;
        }
      };

  /** Separator for the Class-Path manifest attribute value in jar files. */
  private static final Splitter CLASS_PATH_ATTRIBUTE_SEPARATOR =
      Splitter.on(" ").omitEmptyStrings();

  private static final String CLASS_FILE_NAME_EXTENSION = ".class";

  private final ImmutableSet<ResourceInfo> resources;

  private ClassPath(ImmutableSet<ResourceInfo> resources) {
    this.resources = resources;
  }

  /**
   * Returns a {@code ClassPath} representing all classes and resources loadable from {@code
   * classloader} and its parent class loaders.
   *
   * <p><b>Warning:</b> Currently only {@link URLClassLoader} and only {@code file://} urls are
   * supported.
   *
   * @throws IOException if the attempt to read class path resources (jar files or directories)
   *     failed.
   */
  public static ClassPath from(ClassLoader classloader) throws IOException {
    DefaultScanner scanner = new DefaultScanner();
    scanner.scan(classloader);
    return new ClassPath(scanner.getResources());
  }

  /**
   * Returns all resources loadable from the current class path, including the class files of all
   * loadable classes but excluding the "META-INF/MANIFEST.MF" file.
   */
  public ImmutableSet<ResourceInfo> getResources() {
    return resources;
  }

  /**
   * Returns all classes loadable from the current class path.
   *
   * @since 16.0
   */
  public ImmutableSet<ClassInfo> getAllClasses() {
    return FluentIterable.from(resources).filter(ClassInfo.class).toSet();
  }

  /** Returns all top level classes loadable from the current class path. */