/hudson-core/src/main/java/hudson/util/Service.java
http://github.com/hudson/hudson · Java · 115 lines · 71 code · 9 blank · 35 comment · 8 complexity · d7e16f48192055c185c78952b172d739 MD5 · raw file
- /*
- * The MIT License
- *
- * Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
- package hudson.util;
- import java.io.BufferedReader;
- import java.io.IOException;
- import java.io.InputStreamReader;
- import java.net.URL;
- import java.util.Collection;
- import java.util.Enumeration;
- import java.util.List;
- import java.util.ArrayList;
- import java.util.logging.Level;
- import java.util.logging.Logger;
- import static java.util.logging.Level.WARNING;
- /**
- * Load classes by looking up <tt>META-INF/services</tt>.
- *
- * @author Kohsuke Kawaguchi
- */
- public class Service {
- /**
- * Poorman's clone of JDK6 ServiceLoader.
- */
- public static <T> List<T> loadInstances(ClassLoader classLoader, Class<T> type) throws IOException {
- List<T> result = new ArrayList<T>();
- final Enumeration<URL> e = classLoader.getResources("META-INF/services/"+type.getName());
- while (e.hasMoreElements()) {
- URL url = e.nextElement();
- BufferedReader configFile = new BufferedReader(new InputStreamReader(url.openStream(),"UTF-8"));
- String line;
- while ((line = configFile.readLine()) != null) {
- line = line.trim();
- if (line.startsWith("#") || line.length()==0) continue;
- try {
- Class<?> t = classLoader.loadClass(line);
- if (!type.isAssignableFrom(t)) continue; // invalid type
- result.add(type.cast(t.newInstance()));
- } catch (ClassNotFoundException x) {
- LOGGER.log(WARNING,"Failed to load "+line,x);
- } catch (InstantiationException x) {
- LOGGER.log(WARNING,"Failed to load "+line,x);
- } catch (IllegalAccessException x) {
- LOGGER.log(WARNING,"Failed to load "+line,x);
- }
- }
- }
- return result;
- }
- /**
- * Look up <tt>META-INF/service/<i>SPICLASSNAME</i></tt> from the classloader
- * and all the discovered classes into the given collection.
- */
- public static <T> void load(Class<T> spi, ClassLoader cl, Collection<Class<? extends T>> result) {
- try {
- Enumeration<URL> e = cl.getResources("META-INF/services/" + spi.getName());
- while(e.hasMoreElements()) {
- BufferedReader r = null;
- URL url = e.nextElement();
- try {
- r = new BufferedReader(new InputStreamReader(url.openStream(),"UTF-8"));
- String line;
- while((line=r.readLine())!=null) {
- if(line.startsWith("#"))
- continue; // comment line
- line = line.trim();
- if(line.length()==0)
- continue; // empty line. ignore.
- try {
- result.add(cl.loadClass(line).asSubclass(spi));
- } catch (ClassNotFoundException x) {
- LOGGER.log(Level.WARNING, "Failed to load "+line, x);
- }
- }
- } catch (IOException x) {
- LOGGER.log(Level.WARNING, "Failed to load "+url, x);
- } finally {
- r.close();
- }
- }
- } catch (IOException x) {
- LOGGER.log(Level.WARNING, "Failed to look up service providers for "+spi, x);
- }
- }
- private static final Logger LOGGER = Logger.getLogger(Service.class.getName());
- }