| /* |
| * 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.felix.log; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| import org.osgi.service.log.LogEntry; |
| import org.osgi.service.log.LogListener; |
| |
| /** |
| * This class is responsible for asynchronously delivering log messages to |
| * any {@link LogListener} subscribers. A subscriber can be added using the |
| * {@link org.osgi.service.log.LogReaderService#addLogListener(LogListener)} |
| * method. |
| */ |
| final class LogListenerThread extends Thread |
| { |
| // Whether the thread is stopping or not. |
| private boolean m_stopping = false; |
| // The list of entries waiting to be delivered to the log listeners. |
| private final List m_entriesToDeliver = new ArrayList(); |
| // The list of listeners. |
| private final List m_listeners = new ArrayList(); |
| |
| /** |
| * Add an entry to the list of messages to deliver. |
| * @param entry the log entry to deliver |
| */ |
| void addEntry(final LogEntry entry) |
| { |
| synchronized (m_entriesToDeliver) |
| { |
| m_entriesToDeliver.add(entry); |
| m_entriesToDeliver.notifyAll(); |
| } |
| } |
| |
| /** |
| * Add a listener to the list of listeners that are subscribed. |
| * @param listener the listener to add to the list of subscribed listeners |
| */ |
| void addListener(final LogListener listener) |
| { |
| synchronized (m_listeners) |
| { |
| m_listeners.add(listener); |
| } |
| } |
| |
| /** |
| * Remove a listener from the list of listeners that are subscribed. |
| * @param listener the listener to remove from the list of subscribed listeners |
| */ |
| void removeListener(final LogListener listener) |
| { |
| synchronized (m_listeners) |
| { |
| m_listeners.remove(listener); |
| } |
| } |
| |
| /** |
| * Returns the number of listeners that are currently registered. |
| * @return the number of listeners that are currently registered |
| */ |
| int getListenerCount() |
| { |
| return m_listeners.size(); |
| } |
| |
| /** |
| * Stop the thread. This will happen asynchronously. |
| */ |
| void shutdown() |
| { |
| synchronized (m_entriesToDeliver) |
| { |
| m_stopping = true; |
| m_entriesToDeliver.notifyAll(); |
| } |
| } |
| |
| /** |
| * The main method of the thread: waits for new messages to be receieved |
| * and then delivers them to any registered log listeners. |
| */ |
| public void run() |
| { |
| boolean stop = false; |
| |
| for (; !stop;) |
| { |
| synchronized (m_entriesToDeliver) |
| { |
| if (!m_entriesToDeliver.isEmpty()) |
| { |
| LogEntry entry = (LogEntry) m_entriesToDeliver.remove(0); |
| |
| synchronized (m_listeners) |
| { |
| Iterator listenerIt = m_listeners.iterator(); |
| while (listenerIt.hasNext()) |
| { |
| try |
| { |
| LogListener listener = (LogListener) listenerIt.next(); |
| listener.logged(entry); |
| } |
| catch (Throwable t) |
| { |
| // catch and discard any exceptions thrown by the listener |
| } |
| } |
| } |
| } |
| |
| if (m_entriesToDeliver.isEmpty()) |
| { |
| try |
| { |
| m_entriesToDeliver.wait(); |
| } |
| catch (InterruptedException e) |
| { |
| // do nothing |
| } |
| } |
| } |
| |
| if (m_stopping) |
| { |
| stop = true; |
| } |
| } |
| } |
| } |