TimingLogger

TimingLogger.java

/**
 * Use this in a try-with-resources block to automatically implement logging timing.
 */
public class TimingLogger implements AutoCloseable {
  
  private final Logger logger;
  private final String description;
  private final long startTime;
  private final AtomicBoolean closed = new AtomicBoolean(false);

  public class TimingLogger(Logger logger, String description) {
     Objects.requireNonNull(logger, "Logger to write to");
     this.logger = logger;
     
     Objects.requireNonNull(description, "Description of the event we are timing");
     if(description.isEmpty()) {
        throw new IllegalArgumentException("Description may not be empty");
     }
     this.description = description;  
     
     this.startTime = System.currentTimeMillis();
     logger.info(description + " STARTTIME=" + startTime);
  }
  
  public void close() {
    if(!closed.compareAndSet(false, true)) {
      long endTime = System.currentTimeMillis();
      long duration = endTime - startTime;
      logger.info(description + " ENDTIME=" + endTime + " DURATION=" + duration);
    } else {
      throw new IllegalStateException("TimingLogger for " + description + " is already closed");
    }
  }

}