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 java.lang.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 Summary

Tracer.AsyncLogger(java.io.OutputStream os)
Same as Tracer.AsyncLogger(OutputStream, int) with a one-second flush interval.

Tracer.AsyncLogger(java.io.OutputStream os, int flushInterval)
Start/stoppable logger that prints to an OutputStream with flushes every flushInterval milliseconds.

Method Summary

void	log(java.lang.String message) Write msg to the log.
boolean	start() Start logging, that is, printing log entries written using Tracer.Logger.log(String).
boolean	stop() Stop logging, that is, stop printing log entries written using Tracer.Logger.log(String).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Tracer.AsyncLogger

public Tracer.AsyncLogger(java.io.OutputStream os)

Same as Tracer.AsyncLogger(OutputStream, int) with a one-second flush interval.

Parameters:

os - OutputStream to print to.

Tracer.AsyncLogger

public Tracer.AsyncLogger(java.io.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 Detail

log

public void log(java.lang.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

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.