java實現日誌服務

我們在服務器程序中經常用到日誌，日誌對於我們排查問題有很大的幫助。

下面是日誌服務的思路以及實現
思路：多個生產者單個消費者的設計方式，每個調用log的操作都相當於一個生產者，而後臺的日誌線程則相當於消費者。

public class LoggerService {
	private final BlockingQueue<String> queue;
	private final LoggerThread loggerThread;
	private final PrintWriter writer;
	private boolean isShutdown;
	private int reservations;

	public LoggerService(Writer writer) {
		this.queue = new LinkedBlockingQueue<>();
		this.loggerThread = new LoggerThread();
		this.writer = new PrintWriter(writer);
	}

	public void start() {
		loggerThread.start();
	}

	public void stop() {
		synchronized (this) {
			isShutdown = true;
		}
		loggerThread.interrupt();
	}

	public void log(String msg) throws InterruptedException {
		synchronized (this) {
			if (isShutdown) {
				throw new IllegalStateException();
			}
			++reservations;
		}
		queue.put(msg);
	}

	private class LoggerThread extends Thread {
		@Override
		public void run() {
			while (true) {
				try {
					synchronized (LoggerService.this) {
						if (isShutdown && reservations == 0) {
							break;
						}
					}

					String msg = queue.take();
					synchronized (LoggerService.this) {
						--reservations;
					}
					
					writer.println(msg);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} finally {
					writer.close();;
				}

			}

		}
	}

}