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package org.eclipse.equinox.internal.log.stream;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantLock;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.log.LogEntry;
import org.osgi.service.log.LogListener;
import org.osgi.service.log.LogReaderService;
import org.osgi.service.log.stream.LogStreamProvider;
import org.osgi.util.pushstream.PushEvent;
import org.osgi.util.pushstream.PushStream;
import org.osgi.util.pushstream.PushStreamBuilder;
import org.osgi.util.pushstream.PushStreamProvider;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
public class LogStreamFactoryImpl implements BundleActivator, LogStreamProvider, ServiceTrackerCustomizer<LogReaderService, AtomicReference<LogReaderService>>, LogListener {
private final PushStreamProvider pushStreamProvider = new PushStreamProvider();
private final Set<LogEntrySource> logEntrySources = new CopyOnWriteArraySet<>();
private final ExecutorService executor = Executors.newFixedThreadPool(1, new ThreadFactory() {
@Override
public Thread newThread(Runnable r) {
return new Thread(r, "LogStream thread");
}
});
private ServiceTracker<LogReaderService, AtomicReference<LogReaderService>> logReaderService;
BundleContext context;
ReentrantLock eventProducerLock = new ReentrantLock();
/*
* (non-Javadoc)
* @see org.osgi.framework.BundleActivator#start(org.osgi.framework.BundleContext)
*/
public void start(BundleContext context) throws Exception {
this.context = context;
logReaderService = new ServiceTracker<>(context, LogReaderService.class, this);
logReaderService.open();
}
/*
* (non-Javadoc)
* @see org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)
*/
public void stop(BundleContext bundleContext) throws Exception {
logReaderService.close();
executor.shutdown();
}
@Override
public AtomicReference<LogReaderService> addingService(ServiceReference<LogReaderService> reference) {
AtomicReference<LogReaderService> tracked = new AtomicReference<>();
modifiedService(reference, tracked);
return tracked;
}
@Override
public void modifiedService(ServiceReference<LogReaderService> modifiedServiceRef, AtomicReference<LogReaderService> modifiedTracked) {
eventProducerLock.lock();
try {
// Check if the currently used reader service is lower ranked that the modified serviceRef
ServiceReference<LogReaderService> currentServiceRef = logReaderService.getServiceReference();
if (currentServiceRef == null || modifiedServiceRef.compareTo(currentServiceRef) > 0) {
// The modified service reference is higher ranked than the currently used one;
// Use the modified service reference instead.
LogReaderService readerService = context.getService(modifiedServiceRef);
if (readerService != null) {
if (modifiedTracked.get() == null) {
// update our tracked object for the reference with the real service
modifiedTracked.set(readerService);
}
// remove our listener from the currently used service
if (currentServiceRef != null) {
AtomicReference<LogReaderService> currentTracked = logReaderService.getService(currentServiceRef);
if (currentTracked != null) {
LogReaderService currentLogReader = currentTracked.get();
if (currentLogReader != null) {
// we were really using this service;
// remove the our listener and unget the service
currentLogReader.removeLogListener(this);
context.ungetService(currentServiceRef);
// finally null out our tracked reference
currentTracked.set(null);
}
}
}
readerService.addLogListener(this);
}
}
} finally {
eventProducerLock.unlock();
}
}
@Override
public void removedService(ServiceReference<LogReaderService> removedRef, AtomicReference<LogReaderService> removedTracked) {
eventProducerLock.lock();
try {
} finally {
LogReaderService removedLogReader = removedTracked.get();
if (removedLogReader != null) {
removedLogReader.removeLogListener(this);
context.ungetService(removedRef);
removedTracked.set(null);
}
ServiceReference<LogReaderService> currentRef = logReaderService.getServiceReference();
if (currentRef != null) {
AtomicReference<LogReaderService> currentTracked = logReaderService.getService(currentRef);
if (currentTracked != null) {
LogReaderService currentLogReader = currentTracked.get();
if (currentLogReader == null) {
currentLogReader = context.getService(currentRef);
currentTracked.set(currentLogReader);
}
if (currentLogReader != null) {
currentLogReader.addLogListener(this);
}
}
}
eventProducerLock.unlock();
}
}
@Override
public PushStream<LogEntry> createStream(Options... options) {
ServiceTracker<LogReaderService, AtomicReference<LogReaderService>> withHistory = null;
if (options != null) {
for (Options option : options) {
if (Options.HISTORY.equals(option)) {
withHistory = logReaderService;
break;
}
}
}
LogEntrySource logEntrySource = new LogEntrySource(executor, withHistory);
PushStreamBuilder<LogEntry, BlockingQueue<PushEvent<? extends LogEntry>>> streamBuilder = pushStreamProvider.buildStream(logEntrySource);
PushStream<LogEntry> logStream = streamBuilder.unbuffered().withExecutor(executor).create();
logEntrySources.add(logEntrySource);
return logStream;
}
@Override
public void logged(LogEntry entry) {
for (LogEntrySource logEntrySource : logEntrySources) {
logEntrySource.logged(entry);
}
}
}
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