(for trunk) PeriodicTimer

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@12116 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/common/PeriodicTimer.java

@@ -0,0 +1,95 @@
+//==============================================================================
+//	
+//	Copyright (c) 2016-
+//	Authors:
+//	* Joachim Klein <klein@tcs.inf.tu-dresden.de> (TU Dresden)
+//	
+//------------------------------------------------------------------------------
+//	
+//	This file is part of PRISM.
+//	
+//	PRISM is free software; you can redistribute it and/or modify
+//	it under the terms of the GNU General Public License as published by
+//	the Free Software Foundation; either version 2 of the License, or
+//	(at your option) any later version.
+//	
+//	PRISM is distributed in the hope that it will be useful,
+//	but WITHOUT ANY WARRANTY; without even the implied warranty of
+//	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//	GNU General Public License for more details.
+//	
+//	You should have received a copy of the GNU General Public License
+//	along with PRISM; if not, write to the Free Software Foundation,
+//	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//	
+//==============================================================================
+
+package common;
+
+/**
+ * This class keeps time, returning {@code true} for the method {@code triggered()}
+ * when another period of {@code period} milliseconds has elapsed.
+ * <br>
+ * The time is only checked when {@code triggered} is called, so if there
+ * can be long delays between calls to that method, intermediate periods are ignored.
+ * <br>
+ * This class is thus most helpful for "print some update at least after 5 seconds" style
+ * jobs.
+ */
+public class PeriodicTimer
+{
+	/** The period */
+	long period;
+	/** The time when the timer was started */
+	long start;
+	/** The time when the last period was detected */
+	long startOfCurrentPeriod;
+
+	/** Constructor, provide the period in milliseconds, e.g., 5000 = 5 seconds */
+	public PeriodicTimer(long periodMillis)
+	{
+		this.period = periodMillis;
+		this.start = -1;
+		this.startOfCurrentPeriod = -1;
+	}
+
+	/** Start the timer */
+	public void start()
+	{
+		start = System.currentTimeMillis();
+		startOfCurrentPeriod = start;
+	}
+
+	/**
+	 * Returns true if at least 'period' milliseconds have
+	 * elapsed since the last time that this method has
+	 * returned {@code true}.
+	 */
+	public boolean triggered()
+	{
+		long now = System.currentTimeMillis();
+		if (now - startOfCurrentPeriod > period) {
+			startOfCurrentPeriod = now;
+			return true;
+		}
+		return false;
+	}
+
+	/** Get the number of milliseconds since {@code start()} was called */
+	public long elapsedMillisTotal()
+	{
+		long now = System.currentTimeMillis();
+		return now - start;
+	}
+
+	/**
+	 * Get the number of milliseconds since {@code triggered()} has returned {@code true}
+	 * the last time
+	 */
+	public long elapsedMillisInThisPeriod()
+	{
+		long now = System.currentTimeMillis();
+		return now - startOfCurrentPeriod;
+	}
+
+}