Package com.complexible.common.timer

Class Timer

java.lang.Object
com.complexible.common.timer.Timer
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.

Since:
2.0
Version:
2.0
Author:
Evren Sirin
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final long
    NO_TIMEOUT
     
    static final long
    NOT_STARTED
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    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.

  • Method Summary

    Modifier and Type
    Method
    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()
    Return true if timer has been started with a start() call but not has been stopped with a stop() call.
    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()
     

    Methods inherited from class java.lang.Object

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

  • Field Details

  • Constructor Details

    • Timer

      public Timer()
      Create a timer with no name and no parent.

    • Timer

      public Timer(String name)
      Create a timer with no parent.
      Parameters:
      name -

    • Timer

      public Timer(String name, Timer parent)
      Create a timer that has the specified parent timer.
      Parameters:
      name -
      parent -

  • Method Details

    • add

      public void add(Timer timer)
      Update the total time elapsed and number of counts by by adding the values from another timer. This is especially useful if we are running
      Parameters:
      timer -

    • start

      public void start()
      Start time timer by recording the time this function is called. If timer is running when this function is called time is not recorded and only an internal counter is updated.

    • stop

      public long stop()
      Stop the timer, increment the count and update the total time spent. If timer has been started multiple times this function will only decrement the internal counter. Time information is updated only when all starts are evened out by stops.
      Returns:
      Return the total time spent after last start(), -1 if timer is still running, -Long.MAX_VALUE on error

    • reset

      public void reset()
      Reset all the internal counts associated with this timer. After this function call it will be like timer has never been used.

    • restart

      public void restart()
      If started stop the timer and then start it again.

    • check

      public void check()
      Check if the elapsed time is greater than the timeout limit and throw a TimeoutException if that is the case. Check the parent timer if there is one.

    • interrupt

      public void interrupt()
      Interrupt timer so that the next check() call will throw an InterruptedException

    • isStarted

      public boolean isStarted()
      Return true if timer has been started with a start() call but not has been stopped with a stop() call.
      Returns:

    • getName

      public String getName()
      Return the name of this timer.
      Returns:

    • getElapsed

      public long getElapsed()
      Return the time elapsed (in milliseconds) since the last time this timer was started. If the timer is not running now 0 is returned.
      Returns:

    • getTotal

      public long getTotal()
      Return the total time (in milliseconds) spent while this timer was running. If the timer is running when this function is called time elapsed will be discarded. Therefore, it is advised to use this function only with stopped timers.
      Returns:

    • getCount

      public long getCount()
      Return the total number of times this timer has been started and stopped. Note that recursive start operations are computed only once so actual number of times start() function is called may be greater than this amount.
      Returns:

    • getTimeout

      public long getTimeout()
      Return the timeout associated with this timer.
      Returns:

    • getAverage

      public double getAverage()
      Return the total time spent (in milliseconds) divided by the number of times this timer has been ran. If the timer is still running elapsed time is discarded. Therefore, it is advised to use this function only with stopped timers.
      Returns:

    • getLast

      public long getLast()
      Return the total time spent between last start()-stop() period.
      Returns:

    • setTimeout

      public void setTimeout(long timeout)
      Set a timeout limit for this timer. Set the timeout to 0 to disable timeout checking
      Parameters:
      timeout -

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getParent

      public Timer getParent()
      Return the parent timer of this timer depends on. Parent timers are checked hierarchically for timeouts.
      Returns:
      Parent timer or null if there is no such timer.

    • format

      public String format()