/*
* LensKit, an open source recommender systems toolkit.
* Copyright 2010-2014 LensKit Contributors. See CONTRIBUTORS.md.
* Work on LensKit has been funded by the National Science Foundation under
* grants IIS 05-34939, 08-08692, 08-12148, and 10-17697.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.grouplens.lenskit.util;
import com.google.common.collect.ImmutableSetMultimap;
import com.google.common.collect.SetMultimap;
import com.google.common.io.Closer;
import java.io.*;
import java.net.URL;
import java.util.Enumeration;
import java.util.Set;
/**
* Directory to look up where classes might be found. It loads lists of classes from
* <tt>META-INF/classes.lst</tt> and exposes them for use in resolving unresolved imports.
*
* @author <a href="http://www.grouplens.org">GroupLens Research</a>
*/
public class ClassDirectory {
/**
* Get a class directory for the current thread's class loader.
* @return A class directory.
*/
public static ClassDirectory forCurrentClassLoader() {
return forClassLoader(Thread.currentThread().getContextClassLoader());
}
/**
* Get a class directory for a specific class loader.
* @param loader The class loader.
* @return The class directory.
*/
public static ClassDirectory forClassLoader(ClassLoader loader) {
ImmutableSetMultimap.Builder<String,String> mapping = ImmutableSetMultimap.builder();
try {
Enumeration<URL> urls = loader.getResources("META-INF/classes.lst");
while (urls.hasMoreElements()) {
URL url = urls.nextElement();
Closer closer = Closer.create();
try {
InputStream stream = closer.register(url.openStream());
Reader rdr = closer.register(new InputStreamReader(stream, "UTF-8"));
BufferedReader buf = closer.register(new BufferedReader(rdr));
String line = buf.readLine();
while (line != null) {
int idx = line.lastIndexOf('.');
if (idx >= 0) {
String name = line.substring(idx + 1);
String pkg = line.substring(0, idx);
mapping.put(name, pkg);
}
line = buf.readLine();
}
} catch (Throwable th) {
throw closer.rethrow(th);
} finally {
closer.close();
}
}
} catch (IOException e) {
throw new RuntimeException("Error loading class lists", e);
}
return new ClassDirectory(mapping.build());
}
private final SetMultimap<String, String> directory;
private ClassDirectory(SetMultimap<String,String> map) {
directory = map;
}
/**
* Get the packages that contain a class with the specified name.
* @param name The name to look for.
* @return The set of packages (empty if the name is unknown).
*/
public Set<String> getPackages(String name) {
return directory.get(name);
}
}