PackageNamesScanner.java
/*
* Copyright (c) 2012, 2019 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.glassfish.jersey.server.internal.scanning;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.ReflectPermission;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.AccessController;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import org.glassfish.jersey.internal.OsgiRegistry;
import org.glassfish.jersey.internal.util.ReflectionHelper;
import org.glassfish.jersey.internal.util.Tokenizer;
import org.glassfish.jersey.server.internal.AbstractResourceFinderAdapter;
import org.glassfish.jersey.uri.UriComponent;
/**
* A scanner that recursively scans URI-based resources present in a set of
* package names, and nested package names of that set. (Recursive scanning of
* nested packages can be disabled using a proper constructor.)
* <p>
* The URIs for a package name are obtained, by default, by invoking
* {@link ClassLoader#getResources(java.lang.String) } with the parameter that
* is the package name with "." replaced by "/".
* <p>
* Each URI is then scanned using a registered {@link UriSchemeResourceFinderFactory} that
* supports the URI scheme.
* <p>
* The following are registered by default.
* The {@link FileSchemeResourceFinderFactory} for "file" URI schemes.
* The {@link JarZipSchemeResourceFinderFactory} for "jar" or "zip" URI schemes to jar
* resources.
* The {@link VfsSchemeResourceFinderFactory} for the JBoss-based "vfsfile" and "vfszip"
* URI schemes.
* <p>
* Further schemes may be registered by registering an implementation of
* {@link UriSchemeResourceFinderFactory} in the META-INF/services file whose name is the
* the fully qualified class name of {@link UriSchemeResourceFinderFactory}.
* <p>
* If a URI scheme is not supported a {@link ResourceFinderException} will be thrown
* and package scanning deployment will fail.
*
* @author Paul Sandoz
* @author Jakub Podlesak
*/
public final class PackageNamesScanner extends AbstractResourceFinderAdapter {
private final boolean recursive;
private final String[] packages;
private final ClassLoader classloader;
private final Map<String, UriSchemeResourceFinderFactory> finderFactories;
private CompositeResourceFinder compositeResourceFinder;
/**
* Scan a set of packages using a context {@link ClassLoader}.
*
* The {@code recursive} flag determines whether the packages will be scanned recursively
* together with their nested packages ({@code true}) or if only the specified packages
* shall be scanned ({@code false}).
*
* @param packages an array of package names.
* @param recursive if ({@code true} the packages will be scanned recursively together with
* any nested packages, if {@code false} only the explicitly listed packages
* will be scanned.
*/
public PackageNamesScanner(final String[] packages, final boolean recursive) {
this(AccessController.doPrivileged(ReflectionHelper.getContextClassLoaderPA()),
Tokenizer.tokenize(packages, Tokenizer.COMMON_DELIMITERS), recursive);
}
/**
* Scan a set of packages using the provided {@link ClassLoader}.
*
* The {@code recursive} flag determines whether the packages will be scanned recursively
* together with their nested packages ({@code true}) or if only the specified packages
* shall be scanned ({@code false}).
*
* @param classLoader the {@link ClassLoader} to load classes from.
* @param packages an array of package names.
* @param recursive if ({@code true} the packages will be scanned recursively together with
* any nested packages, if {@code false} only the explicitly listed packages
* will be scanned.
*/
public PackageNamesScanner(final ClassLoader classLoader, final String[] packages, final boolean recursive) {
this.recursive = recursive;
this.packages = packages.clone();
this.classloader = classLoader;
this.finderFactories = new HashMap<>();
add(new JarZipSchemeResourceFinderFactory());
add(new FileSchemeResourceFinderFactory());
add(new VfsSchemeResourceFinderFactory());
add(new BundleSchemeResourceFinderFactory());
// TODO - Services?
// for (UriSchemeResourceFinderFactory s : ServiceFinder.find(UriSchemeResourceFinderFactory.class)) {
// add(s);
// }
final OsgiRegistry osgiRegistry = ReflectionHelper.getOsgiRegistryInstance();
if (osgiRegistry != null) {
setResourcesProvider(new PackageNamesScanner.ResourcesProvider() {
@Override
public Enumeration<URL> getResources(final String packagePath, final ClassLoader classLoader) throws IOException {
return osgiRegistry.getPackageResources(packagePath, classLoader, recursive);
}
});
}
init();
}
private void add(final UriSchemeResourceFinderFactory uriSchemeResourceFinderFactory) {
for (final String scheme : uriSchemeResourceFinderFactory.getSchemes()) {
finderFactories.put(scheme.toLowerCase(Locale.ROOT), uriSchemeResourceFinderFactory);
}
}
@Override
public boolean hasNext() {
return compositeResourceFinder.hasNext();
}
@Override
public String next() {
return compositeResourceFinder.next();
}
@Override
public InputStream open() {
return compositeResourceFinder.open();
}
@Override
public void close() {
compositeResourceFinder.close();
}
@Override
public void reset() {
close();
init();
}
public ClassLoader getClassloader() {
return classloader;
}
private void init() {
compositeResourceFinder = new CompositeResourceFinder();
for (final String p : packages) {
try {
final Enumeration<URL> urls =
ResourcesProvider.getInstance().getResources(p.replace('.', '/'), classloader);
while (urls.hasMoreElements()) {
try {
addResourceFinder(toURI(urls.nextElement()));
} catch (final URISyntaxException e) {
throw new ResourceFinderException("Error when converting a URL to a URI", e);
}
}
} catch (final IOException e) {
throw new ResourceFinderException("IO error when package scanning jar", e);
}
}
}
/**
* Find resources with a given name and class loader.
*/
public abstract static class ResourcesProvider {
private static volatile ResourcesProvider provider;
private static ResourcesProvider getInstance() {
// Double-check idiom for lazy initialization
ResourcesProvider result = provider;
if (result == null) { // first check without locking
synchronized (ResourcesProvider.class) {
result = provider;
if (result == null) { // second check with locking
provider = result = new ResourcesProvider() {
@Override
public Enumeration<URL> getResources(final String name, final ClassLoader cl)
throws IOException {
return cl.getResources(name);
}
};
}
}
}
return result;
}
private static void setInstance(final ResourcesProvider provider) throws SecurityException {
final SecurityManager security = System.getSecurityManager();
if (security != null) {
final ReflectPermission rp = new ReflectPermission("suppressAccessChecks");
security.checkPermission(rp);
}
synchronized (ResourcesProvider.class) {
ResourcesProvider.provider = provider;
}
}
/**
* Find all resources with the given name using a class loader.
*
* @param cl the class loader use to find the resources
* @param name the resource name
* @return An enumeration of URL objects for the resource.
* If no resources could be found, the enumeration will be empty.
* Resources that the class loader doesn't have access to will
* not be in the enumeration.
* @throws IOException if I/O errors occur
*/
public abstract Enumeration<URL> getResources(String name, ClassLoader cl) throws IOException;
}
/**
* Set the {@link ResourcesProvider} implementation to find resources.
* <p>
* This method should be invoked before any package scanning is performed
* otherwise the functionality method will be utilized.
*
* @param provider the resources provider.
* @throws SecurityException if the resources provider cannot be set.
*/
public static void setResourcesProvider(final ResourcesProvider provider) throws SecurityException {
ResourcesProvider.setInstance(provider);
}
private void addResourceFinder(final URI u) {
final UriSchemeResourceFinderFactory finderFactory = finderFactories.get(u.getScheme().toLowerCase(Locale.ROOT));
if (finderFactory != null) {
compositeResourceFinder.push(finderFactory.create(u, recursive));
} else {
throw new ResourceFinderException("The URI scheme " + u.getScheme()
+ " of the URI " + u
+ " is not supported. Package scanning deployment is not"
+ " supported for such URIs."
+ "\nTry using a different deployment mechanism such as"
+ " explicitly declaring root resource and provider classes"
+ " using an extension of javax.ws.rs.core.Application");
}
}
private URI toURI(final URL url) throws URISyntaxException {
try {
return url.toURI();
} catch (final URISyntaxException e) {
// Work around bug where some URLs are incorrectly encoded.
// This can occur when certain class loaders are utilized
// to obtain URLs for resources.
return URI.create(toExternalForm(url));
}
}
private String toExternalForm(final URL u) {
// pre-compute length of StringBuffer
int len = u.getProtocol().length() + 1;
if (u.getAuthority() != null && u.getAuthority().length() > 0) {
len += 2 + u.getAuthority().length();
}
if (u.getPath() != null) {
len += u.getPath().length();
}
if (u.getQuery() != null) {
len += 1 + u.getQuery().length();
}
if (u.getRef() != null) {
len += 1 + u.getRef().length();
}
final StringBuilder result = new StringBuilder(len);
result.append(u.getProtocol());
result.append(":");
if (u.getAuthority() != null && u.getAuthority().length() > 0) {
result.append("//");
result.append(u.getAuthority());
}
if (u.getPath() != null) {
result.append(UriComponent.contextualEncode(u.getPath(), UriComponent.Type.PATH));
}
if (u.getQuery() != null) {
result.append('?');
result.append(UriComponent.contextualEncode(u.getQuery(), UriComponent.Type.QUERY));
}
if (u.getRef() != null) {
result.append("#");
result.append(u.getRef());
}
return result.toString();
}
}