public class Timer extends Object
Class used to keep track how much time is spent for a specific operation. Timers are primarily used to display info about performance. A timer is started at the beginning of a function and is stopped at the end of that function (special care needed when there are multiple return commands in a function because the status of unstopped timers is undefined). A timer also stores how many times the timer has been started so average time spent in a function can be computed.
When a timer is used in a recursive function it will typically be started multiple times. Timer class will only measure the time spent in the first call. This is done by counting how many times a timer is started and time spent is computed only when the number of stop() calls evens out the start() calls. It is the programmer's responsibility to make sure each start() is stopped by a stop() call.
Each timer may be associated with a timeout limit. This means that time spent between start() and stop() calls should be less than the timeout specified. Timeouts will only be checked when check() function is called. If check() function is not called setting timeouts has no effect. It is up to the programmer to decide when and how many times a timer will be checked.
There may be a dependency between timers. For example, classification, realization and entailment operations all use consistency checks. If something goes wrong inside a consistency check and that operation does not finish in a reasonable time, the timeout on the parent timer may expire. To handle such cases, a timer may be associated with a parent timer so every time a timer is checked for a timeout, its parent timer will also be checked. Normally, we would like to associate many parents with a timer but for efficiency reasons (looping over an array each time is expensive) each timer is allowed to have only one parent.
Timers
class stores a set of timers and provides functions to start, stop and
check timers.
Timers
Modifier and Type | Field and Description |
---|---|
static long |
NO_TIMEOUT |
static long |
NOT_STARTED |
Constructor and Description |
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Timer()
Create a timer with no name and no parent.
|
Timer(String name)
Create a timer with no parent.
|
Timer(String name,
Timer parent)
Create a timer that has the specified parent timer.
|
Modifier and Type | Method and Description |
---|---|
void |
add(Timer timer)
Update the total time elapsed and number of counts by by adding the values from another
timer.
|
void |
check()
Check if the elapsed time is greater than the timeout limit and throw a TimeoutException
if that is the case.
|
String |
format() |
double |
getAverage()
Return the total time spent (in milliseconds) divided by the number of times this timer
has been ran.
|
long |
getCount()
Return the total number of times this timer has been started and stopped.
|
long |
getElapsed()
Return the time elapsed (in milliseconds) since the last time this timer was started.
|
long |
getLast()
Return the total time spent between last start()-stop() period.
|
String |
getName()
Return the name of this timer.
|
Timer |
getParent()
Return the parent timer of this timer depends on.
|
long |
getTimeout()
Return the timeout associated with this timer.
|
long |
getTotal()
Return the total time (in milliseconds) spent while this timer was running.
|
void |
interrupt()
Interrupt timer so that the next check() call will throw an InterruptedException
|
boolean |
isStarted()
|
void |
reset()
Reset all the internal counts associated with this timer.
|
void |
restart()
If started stop the timer and then start it again.
|
void |
setTimeout(long timeout)
Set a timeout limit for this timer.
|
void |
start()
Start time timer by recording the time this function is called.
|
long |
stop()
Stop the timer, increment the count and update the total time spent.
|
String |
toString() |
public static final long NOT_STARTED
public static final long NO_TIMEOUT
public Timer()
public Timer(String name)
name
- public void add(Timer timer)
timer
- public void start()
public long stop()
public void reset()
public void restart()
public void check()
public void interrupt()
public boolean isStarted()
start()
call but not has been
stopped with a stop()
call.public String getName()
public long getElapsed()
public long getTotal()
public long getCount()
start()
function is called may be greater than this amount.public long getTimeout()
public double getAverage()
public long getLast()
public void setTimeout(long timeout)
timeout
- public Timer getParent()
public String format()
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