diff options
Diffstat (limited to 'timer/com/vladium/utils')
| -rw-r--r-- | timer/com/vladium/utils/timing/ITimer.java | 54 | ||||
| -rw-r--r-- | timer/com/vladium/utils/timing/ITimerConstants.java | 31 | ||||
| -rw-r--r-- | timer/com/vladium/utils/timing/JavaSystemTimer.java | 74 | ||||
| -rw-r--r-- | timer/com/vladium/utils/timing/TimerFactory.java | 74 |
4 files changed, 233 insertions, 0 deletions
diff --git a/timer/com/vladium/utils/timing/ITimer.java b/timer/com/vladium/utils/timing/ITimer.java new file mode 100644 index 0000000..98029b1 --- /dev/null +++ b/timer/com/vladium/utils/timing/ITimer.java @@ -0,0 +1,54 @@ + +package com.vladium.utils.timing; + +// ---------------------------------------------------------------------------- +/** + * A simple interface for measuring time intervals. An instance of this goes + * through the following lifecycle states: + * <DL> + * <DT> <EM>ready</EM> + * <DD> timer is ready to start a new measurement + * <DT> <EM>started</EM> + * <DD> timer has recorded the starting time interval point + * <DT> <EM>stopped</EM> + * <DD> timer has recorded the ending time interval point + * </DL> + * See individual methods for details.<P> + * + * If this library has been compiled with {@link ITimerConstants#DO_STATE_CHECKS} + * set to 'true' the implementation will enforce this lifecycle model and throw + * IllegalStateException when it is violated. + * + * @author (C) <a href="mailto:vroubtsov@illinoisalumni.org">Vlad Roubtsov</a>, 2002 + */ +public interface ITimer +{ + // public: ................................................................ + + /** + * Starts a new time interval and advances this timer instance to 'started' + * state. This method can be called from 'ready' state only.
*/ + void start (); + + /** + * Terminates the current time interval and advances this timer instance to + * 'stopped' state. Interval duration will be available via + * {@link #getDuration()} method. This method can be called from 'started' + * state only.
*/ + void stop (); + + /** + * Returns the duration of the time interval that elapsed between the last + * calls to {@link #start()} and {@link #stop()}. This method can be called + * any number of times from 'stopped' state and will return the same value + * each time.<P> + *
* @return interval duration in milliseconds
*/ + double getDuration (); + + /** + * This method can be called from any state and will reset this timer + * instance back to 'ready' state.
*/ + void reset (); + +} // end of interface +// ---------------------------------------------------------------------------- diff --git a/timer/com/vladium/utils/timing/ITimerConstants.java b/timer/com/vladium/utils/timing/ITimerConstants.java new file mode 100644 index 0000000..29435ae --- /dev/null +++ b/timer/com/vladium/utils/timing/ITimerConstants.java @@ -0,0 +1,31 @@ + +package com.vladium.utils.timing; + +// ---------------------------------------------------------------------------- +/** + * A package-private collection of constants used by {@link ITimer} implementations + * in <code>HRTimer</code> and <code>JavaSystemTimer</code> classes. + * + * @author (C) <a href="mailto:vroubtsov@illinoisalumni.org">Vlad Roubtsov</a>, 2002 + */ +interface ITimerConstants +{ + // public: ................................................................ + + /** + * Conditional compilation flag to enable/disable state checking in timer + * implementations. Just about the only reason you might want to disable + * this is to reduce the timer overhead, but in practice the gain is very + * small.
*/ + static final boolean DO_STATE_CHECKS = true; + + /** + * Timer state enumeration.
*/ + static final int STATE_READY = 0, STATE_STARTED = 1, STATE_STOPPED = 2; + + /** + * User-friendly timer state names indexed by their state values.
*/ + static final String [] STATE_NAMES = {"READY", "STARTED", "STOPPED"}; + +} // end of interface +// ---------------------------------------------------------------------------- diff --git a/timer/com/vladium/utils/timing/JavaSystemTimer.java b/timer/com/vladium/utils/timing/JavaSystemTimer.java new file mode 100644 index 0000000..e3f3b48 --- /dev/null +++ b/timer/com/vladium/utils/timing/JavaSystemTimer.java @@ -0,0 +1,74 @@ + +package com.vladium.utils.timing; + +// ---------------------------------------------------------------------------- +/** + * A package-private implementation of {@link ITimer} based around Java system + * timer [<code>System.currentTimeMillis()</code> method]. It is used when + * <code>HRTimer</code> implementation is unavailable.<P> + * + * {@link TimerFactory} acts as the Factory for this class.<P> + * + * MT-safety: an instance of this class is safe to be used within the same + * thread only. + * + * @author (C) <a href="mailto:vroubtsov@illinoisalumni.org">Vlad Roubtsov</a>, 2002 + */ +final class JavaSystemTimer implements ITimer, ITimerConstants +{ + // public: ................................................................ + + public void start () + { + if (DO_STATE_CHECKS) + { + if (m_state != STATE_READY) + throw new IllegalStateException (this + ": start() must be called from READY state, current state is " + STATE_NAMES [m_state]); + } + + if (DO_STATE_CHECKS) m_state = STATE_STARTED; + m_data = System.currentTimeMillis (); + } + + public void stop () + { + // latch stop time in a local var before doing anything else: + final long data = System.currentTimeMillis (); + + if (DO_STATE_CHECKS) + { + if (m_state != STATE_STARTED) + throw new IllegalStateException (this + ": stop() must be called from STARTED state, current state is " + STATE_NAMES [m_state]); + } + + m_data = data - m_data; + if (DO_STATE_CHECKS) m_state = STATE_STOPPED; + } + + public double getDuration () + { + if (DO_STATE_CHECKS) + { + if (m_state != STATE_STOPPED) + throw new IllegalStateException (this + ": getDuration() must be called from STOPPED state, current state is " + STATE_NAMES [m_state]); + } + + return m_data; + } + + public void reset () + { + if (DO_STATE_CHECKS) m_state = STATE_READY; + } + + // protected: ............................................................. + + // package: ............................................................... + + // private: ............................................................... + + private int m_state; // used to keep track of timer state + private long m_data; // timing data + +} // end of class +// ---------------------------------------------------------------------------- diff --git a/timer/com/vladium/utils/timing/TimerFactory.java b/timer/com/vladium/utils/timing/TimerFactory.java new file mode 100644 index 0000000..ae127c5 --- /dev/null +++ b/timer/com/vladium/utils/timing/TimerFactory.java @@ -0,0 +1,74 @@ + +package com.vladium.utils.timing; + +// ---------------------------------------------------------------------------- +/** + * This non-instantiable non-extendible class acts as a Factory for {@link ITimer} + * implementations. + * + * @author (C) <a href="mailto:vroubtsov@illinoisalumni.org">Vlad Roubtsov</a>, 2002 + */ +public abstract class TimerFactory +{ + // public: ................................................................ + + private static final String HRTIMER_LIB = "hrtlib"; + + /** + * Creates a new instance of {@link ITimer} which is returned in 'ready' + * state. If the JNI-based/high-resolution implementation is not available + * this will return an instance of <code>JavaSystemTimer</code>, so this + * method is guaranteed not to fail. + * + * @return ITimer a new timer instance in 'ready' state [never null]
*/ + + public static void initialize(String path) { + + UnsatisfiedLinkError exception = null; + + try { + System.loadLibrary (HRTIMER_LIB); + } catch (UnsatisfiedLinkError e) { + if(path != null) { + try { + System.load(path); + } catch (UnsatisfiedLinkError ex) { + exception = ex; + } + } else { + exception = e; + } + } + + if(exception != null) { + System.out.println ("native lib '" + HRTIMER_LIB + + "' not found in 'java.library.path': " + + System.getProperty ("java.library.path") + +path==null?"":(" or in "+path)); + + throw exception; // re-throw + } + } + + public static ITimer newTimer () + { +// try +// { + return new HRTimer (); +// } +// catch (Throwable t) +// { +// return new JavaSystemTimer (); +// } + } + + // protected: ............................................................. + + // package: ............................................................... + + // private: ............................................................... + + private TimerFactory () {} // prevent subclassing + +} // end of class +// ---------------------------------------------------------------------------- |