Java Reference
In-Depth Information
MemoryWatchTask
extends the abstract
TimerTask
to define a task that
prints the current free and total memory, prefixed by the current time.
TimerTask
implements the
Runnable
interface, and its
run
method is what
is invoked by a
Timer
object when a task is to be run. Because the setup
code told
timer
to execute once a second, the thread used by
timer
will
wait one second between task executions.
TimerTask
has three methods:
public abstract void
run()
Defines the action to be performed by this
TimerTask
.
public boolean
cancel()
Cancels this
TimerTask
so that it will never run again (or at all
if it hasn't run yet). Returns
true
if the task was scheduled
for repeated execution or was a once-only task that had not
yet been run. Returns
false
if the task was a once-only task
that has already run, the task was never scheduled, or the
task has previously been cancelled. Essentially, this method
returns
true
if it prevented the task from having a scheduled
execution.
public long
scheduledExecutionTime()
Returns the scheduled execution time of the most recent ac-
tual execution (possibly the in-progress execution) of this
TimerTask
. The returned value represents the time in milli-
seconds. This method is most often used inside
run
to see if
the current execution of the task occurred soon enough to
warrant execution; if the task was delayed too long
run
may
decide not to do anything.
