Added a Stopwatch class and tests to make sure it works propperly

mattrixwv/Stopwatch.java

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+//Java/JavaClasses/Mattrixwv/Stopwatch.java
+//Matthew Ellison (Mattrixwv)
+// Created: 03-01-19
+//Modified: 03-01-19
+//This file contains a class that is used to time the execution time of other programs
+
+
+package mattrixwv;
+
+
+public class Stopwatch{
+	private Long startTime;
+	private Long stopTime;
+	//Constructor makes sure all values are set to defaults
+	public Stopwatch(){
+		//Make sure both values are null so it is easier to detect incorrect function calling order
+		startTime = null;
+		stopTime = null;
+	}
+	//Returns a long with the elapsed time in nanoseconds. Used by other functions to get the time before converting it to the correct resolution
+	private Long getTime(){
+		if(startTime == null){
+			///This should throw an exception instead of returning 0
+			return 0L;
+		}
+		else if(stopTime == null){
+			return System.nanoTime() - startTime;
+		}
+		else{
+			return stopTime - startTime;
+		}
+	}
+	//An enum that helps keep track of how many times the time has been reduced in the getStr function
+	private enum TIME_RESOLUTION{ NANOSECOND, MICROSECOND, MILLISECOND, SECOND, MINUTE, HOUR, ERROR }
+	//Simulates starting a stopwatch by saving the time
+	public void start(){
+		//Get the time as close to calling the function as possible
+		startTime = System.nanoTime();
+		//Make sure the stop time is reset to 0
+		stopTime = null;
+	}
+	//SImulates stoping a stopwatch by saving the time
+	public void stop(){
+		//Set the stopTime as close to call time as possible
+		stopTime = System.nanoTime();
+		//If the startTime has not been set then reset stopTime
+		if(startTime == null){
+			stopTime = null;
+		}
+	}
+	//Resets all variables in the stopwatch
+	public void reset(){
+		//Make sure all variables are reset correctly
+		startTime = null;
+		stopTime = null;
+	}
+	//Returns the time in nanoseconds
+	public double getNano(){
+		return getTime().doubleValue();
+	}
+	//Returns the time in microseconds
+	public double getMicro(){
+		return getTime().doubleValue() / 1000D;
+	}
+	//Returns the time in milliseconds
+	public double getMilli(){
+		return getTime().doubleValue() / 1000000D;
+	}
+	//Returns the time in seconds
+	public double getSecond(){
+		return getTime().doubleValue() / 1000000000D;
+	}
+	//Returns the time in minutes
+	public double getMinute(){
+		return getTime().doubleValue() / 60000000000D;
+	}
+	//Returns the time in hours
+	public double getHour(){
+		return getTime().doubleValue() / 3600000000000D;
+	}
+	//Returns the time as a string at the 'best' resolution. (Goal is xxx.xxx)
+	public String getStr(){
+		//Get the current duration from time
+		Double duration = getTime().doubleValue();
+		//Reduce the number to the appropriate number of digits. (xxx.x). This loop works down to seconds
+		TIME_RESOLUTION resolution;
+		for(resolution = TIME_RESOLUTION.NANOSECOND;(resolution.ordinal() < TIME_RESOLUTION.SECOND.ordinal()) && (duration >= 1000);resolution = TIME_RESOLUTION.values()[resolution.ordinal() + 1]){
+			duration /= 1000;
+		}
+		//Check if the duration needs reduced to minutes
+		if(duration >= 1000){
+			//Reduce to minutes
+			duration /= 60;
+			resolution = TIME_RESOLUTION.values()[resolution.ordinal() + 1];
+		}
+		//Check if the duration needs reduced to hours
+		if(duration >= 1000){
+			//Reduce to hours
+			duration /= 60;
+			resolution = TIME_RESOLUTION.values()[resolution.ordinal() + 1];
+		}
+
+		//Turn the number into a string
+		Double durationFraction = ((duration % 1) * 100);
+		String time = String.format("% 3d.%03d", duration.intValue(), durationFraction.intValue());
+
+		//Tack on the appropriate suffix for resolution
+		switch(resolution){
+			case NANOSECOND: time += " nanoseconds"; break;
+			case MICROSECOND: time += " microseconds"; break;
+			case MILLISECOND: time += " milliseconds"; break;
+			case SECOND: time += " seconds"; break;
+			case MINUTE: time += " minutes"; break;
+			case HOUR: time += " hours"; break;
+			case ERROR:
+			default: time = "There was an error computing the time"; break;	///This should throw an error instead
+		}
+		//Return the string
+		return time;
+	}
+}

testStopwatch.java

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+//Java/JavaClasses/testStopwatch.java
+//Matthew Ellison
+// Created: 03-01-19
+//Modified: 03-01-19
+//This class is used to test that stopwatch does what it is supposed to do (approximately)
+
+
+import mattrixwv.Stopwatch;
+
+
+public class testStopwatch{
+	private static final int NUM_TO_RUN = 100000;
+    public static void main(String[] argv){
+		Boolean failed = false;	//A flag to determine if all tests were passed
+		//Print the test begin message
+		System.out.println("Begin test");
+		//Describe which test is being performed
+		System.out.println("Starting loop");
+		//Start the timer
+		Stopwatch timer = new Stopwatch();
+		timer.start();
+		for(int cnt = 0;cnt < NUM_TO_RUN;++cnt){
+			System.out.print(cnt);
+		}
+		//Stop the timer
+		timer.stop();
+		System.out.println("\nLoop completed");
+
+		//Check that the different resolutions work out correctly
+		System.out.println("Checking that resolutions line up correctly");
+		Double nano = timer.getNano();
+		if(timer.getMicro() != (nano.doubleValue() / 1000D)){
+			System.out.println("Error on microsecond resolution");
+			failed = true;
+		}
+		else if(timer.getMilli() != (nano.doubleValue() / 1000000D)){
+			System.out.println("Error on millisecond resolution");
+			failed = true;
+		}
+		else if(timer.getSecond() != (nano.doubleValue() / 1000000000D)){
+			System.out.println("Error on second resolution");
+			failed = true;
+		}
+		else if(timer.getMinute() != (nano.doubleValue() / 60000000000D)){
+			System.out.println("Error on minute resolution");
+			failed = true;
+		}
+		else if(timer.getHour() != (nano.doubleValue() / 3600000000000D)){
+			System.out.println("Error on hour resolution");
+			failed = true;
+		}
+		else{
+			System.out.println("All time resolution tests completed successfully");
+		}
+		System.out.println("Completed resolution checking");
+
+		//Print the results
+		System.out.printf("The timer results in: %s\n", timer.getStr());
+
+		if(!failed){
+			System.out.println("All tests completed successfully");
+		}
+		else{
+			System.out.println("Test failed. Try again!");
+		}
+    }
+}