Package com.rabbitmq.tools

Class Tracer.AsyncLogger

java.lang.Object
com.rabbitmq.tools.Tracer.AsyncLogger
All Implemented Interfaces:
Tracer.Logger
Enclosing class:
Tracer
public static class Tracer.AsyncLogger extends Object implements Tracer.Logger
A Tracer.Logger designed to print Strings to a designated OutputStream on a private thread.

Strings are read from a private queue and printed to a buffered PrintStream which is periodically flushed.

When instantiated the private queue is created (an in-memory ArrayBlockingQueue in this implementation) and when start()ed the private thread is created and started unless it is already present. An Tracer.AsyncLogger may be started many times, but only one thread is created.

When stop()ed either the number of starts is decremented, or, if this count reaches zero, a special element is queued which causes the private thread to end when encountered.

If the private thread is interrupted, the thread will also end, and the count set to zero, This will cause subsequent stop()s to be ignored, and the next start() will create a new thread.

log(String) never blocks unless the private queue is full; this may never un-block if the Tracer.Logger is stopped.

  • Constructor Details

    • AsyncLogger

      public AsyncLogger(OutputStream os)
      Same as
      invalid @link 
      {@link #Tracer.AsyncLogger(OutputStream, int)
      } with a one-second flush interval.
      Parameters:
      os - OutputStream to print to.

    • AsyncLogger

      public AsyncLogger(OutputStream os, int flushInterval)
      Start/stoppable logger that prints to an OutputStream with flushes every flushInterval milliseconds.
      Parameters:
      os - OutputStream to print to.
      flushInterval - in milliseconds, time between flushes.

  • Method Details

    • log

      public void log(String message)
      Description copied from interface: Tracer.Logger
      Write msg to the log. This may block, and may block indefinitely if the logger is stopped.
      Specified by:
      log in interface Tracer.Logger
      Parameters:
      message -

    • start

      public boolean start()
      Description copied from interface: Tracer.Logger
      Start logging, that is, printing log entries written using Tracer.Logger.log(String). Multiple successive starts are equivalent to a single start.
      Specified by:
      start in interface Tracer.Logger
      Returns:
      true if start actually started the logger; false otherwise.

    • stop

      public boolean stop()
      Description copied from interface: Tracer.Logger
      Stop logging, that is, stop printing log entries written using Tracer.Logger.log(String). Flush preceding writes. The logger can only be stopped if started. Multiple successive stops are equivalent to a single stop.
      Specified by:
      stop in interface Tracer.Logger
      Returns:
      true if stop actually stopped the logger; false otherwise.