| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.servicemix.specs.locator; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.locks.ReadWriteLock; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| |
| public class OsgiLocator { |
| |
| public static final long DEFAULT_TIMEOUT = 0l; |
| public static final String TIMEOUT = "org.apache.servicemix.specs.timeout"; |
| |
| private static Map<String, List<Callable<Class>>> factories; |
| |
| private static ReadWriteLock lock = new ReentrantReadWriteLock(); |
| |
| private OsgiLocator() { |
| } |
| |
| public static void unregister(String id, Callable<Class> factory) { |
| lock.writeLock().lock(); |
| try { |
| if (factories != null) { |
| List<Callable<Class>> l = factories.get(id); |
| if (l != null) { |
| l.remove(factory); |
| } |
| } |
| } finally { |
| lock.writeLock().unlock(); |
| } |
| } |
| |
| public static void register(String id, Callable<Class> factory) { |
| lock.writeLock().lock(); |
| try { |
| if (factories == null) { |
| factories = new HashMap<String, List<Callable<Class>>>(); |
| } |
| List<Callable<Class>> l = factories.get(id); |
| if (l == null) { |
| l = new ArrayList<Callable<Class>>(); |
| factories.put(id, l); |
| } |
| l.add(0, factory); |
| synchronized (lock) { |
| lock.notifyAll(); |
| } |
| } finally { |
| lock.writeLock().unlock(); |
| } |
| } |
| |
| |
| public static <T> Class<? extends T> locate(Class<T> factoryId) { |
| return locate(factoryId, factoryId.getName()); |
| } |
| |
| private static long getTimeout() { |
| long timeout = DEFAULT_TIMEOUT; |
| try { |
| String prop = System.getProperty(TIMEOUT); |
| if (prop != null) { |
| timeout = Long.parseLong(prop); |
| } |
| } catch (Throwable t) { } |
| return timeout; |
| } |
| |
| public static <T> Class<? extends T> locate(Class<T> factoryClass, String factoryId) { |
| long timeout = getTimeout(); |
| if (timeout <= 0) { |
| return doLocate(factoryClass, factoryId); |
| } |
| long t0 = System.currentTimeMillis(); |
| long t1 = t0; |
| while (t1 - t0 < timeout) { |
| Class<? extends T> impl = doLocate(factoryClass, factoryId); |
| if (impl != null) { |
| return impl; |
| } |
| synchronized (lock) { |
| try { |
| lock.wait(timeout - (t1 - t0)); |
| } catch (InterruptedException e) { |
| return null; |
| } |
| } |
| t1 = System.currentTimeMillis(); |
| } |
| return null; |
| } |
| |
| private static <T> Class<? extends T> doLocate(Class<T> factoryClass, String factoryId) { |
| lock.readLock().lock(); |
| try { |
| if (factories != null) { |
| List<Callable<Class>> l = factories.get(factoryId); |
| if (l != null && !l.isEmpty()) { |
| // look up the System property first |
| String factoryClassName = System.getProperty(factoryId); |
| try { |
| for (Callable<Class> i : l) { |
| Class c = null; |
| try { |
| c = i.call(); |
| } catch (Exception ex) { |
| // do nothing here |
| } |
| if (c != null && factoryClass == c.getClassLoader().loadClass(factoryClass.getName()) |
| && (factoryClassName == null || c.getName().equals(factoryClassName))) |
| { |
| return c; |
| } |
| } |
| } catch (Exception ex) { |
| // do nothing here |
| } |
| } |
| } |
| return null; |
| } finally { |
| lock.readLock().unlock(); |
| } |
| } |
| |
| public static <T> List<Class<? extends T>> locateAll(Class<T> factoryId) { |
| return locateAll(factoryId, factoryId.getName()); |
| } |
| |
| public static <T> List<Class<? extends T>> locateAll(Class<T> factoryClass, String factoryId) { |
| lock.readLock().lock(); |
| try { |
| List<Class<? extends T>> classes = new ArrayList<Class<? extends T>>(); |
| if (factories != null) { |
| List<Callable<Class>> l = factories.get(factoryId); |
| if (l != null) { |
| for (Callable<Class> i : l) { |
| try { |
| Class c = i.call(); |
| if (c != null && factoryClass.isAssignableFrom(c)) { |
| classes.add(c); |
| } |
| } catch (Exception e) { |
| } |
| } |
| } |
| } |
| return classes; |
| } finally { |
| lock.readLock().unlock(); |
| } |
| } |
| |
| } |