Trivial Swift and Java Timing facility...

Time.java

/**
 * new Time() creates a running timer
 * reporting on a running timer is fine
 * each run() resets the start time and each stop() after run() accumulates time
 *
 * e.g.
 * time = new Time()
 * ...
 * time.ms();
 *
 * OR
 *
 * time = new Time();
 * ...
 * time.run()
 * ...
 * time.stop() /// repeat run() ... stop()
 * ...
 * time.ms()
 * OR
 * time.toString()
 *
 * Note: This is obviously not thread safe.
 *
 * This is public domain code.
 * @author pat
 */
public class Time
{
    // if -1, elapsed has it all, else elapsed + now()-start
    volatile public long start = -1;
    volatile long elapsed;
    public String name;

    protected Time( long elapsed ) {
        this.elapsed = elapsed;
    }

    public Time( String name )
    {
        this();
        this.name = name;
    }

    public Time() {
        run();
    }

    /**
     * run()/stop() accumulate time
     */
    public void run()
    {
        start=now();
    }

    /**
     * run()/stop() accumulate time
     */
    public void stop()
    {
        elapsed += now() - start;
        start=-1;
    }

    public long ms()
    {
        if ( start == -1 ) {
            return elapsed;
        } else {
            return ( now() - start ) + elapsed;
        }
    }
    public float s()
    {
        return 1.0f * ms() / 1000;
    }

    public static long now() {
        return System.currentTimeMillis();
    }

    public boolean gt( long ms ) {
        return ms() > ms ;
    }

    /**
     * Get a new Time instance that is the time divided over the number specified.
     * e.g. time.per( numUsers ) might represent the time consumed by each user operation.
     * @param num
     * @return
     */
    public Time per( int num )
    {
        return new Time( ms() / num );
    }

    /**
     * e.g. given num iterations returns the rate in iterations per second.
     */
    public Float rate( int num ) {
        return num/s();
    }


    public String toString()
    {
        if ( ms() < 1000 ) {
            return ms()+"ms";
        } else
        {
            return String.format( "%.1fs", s() );
        }
    }

}

Time.swift

import Foundation

/**
 * new Time() creates a running timer
 * reporting on a running timer is fine
 * each run() resets the start time and each stop() after run() accumulates time
 *
 * e.g.
 * time = new Time()
 * ...
 * time.ms();
 *
 * OR
 *
 * time = new Time();
 * ...
 * time.run()
 * ...
 * time.stop() /// repeat run() ... stop()
 * ...
 * time.ms()
 * OR
 * time.toString()
 *
 * Note: This is obviously not thread safe.
 *
 * This is public domain code.
 * @author pat
 */
public class Time : CustomStringConvertible
{
    // if -1, elapsed has it all, else elapsed + now()-start
    /*volatile*/ public var start : UInt64 = 0
    /*volatile*/ var elapsed : UInt64 = 0
    public var name : String!

    internal init( _ _elapsed : UInt64 ) {
        self.elapsed = _elapsed;
    }

    public convenience init( _ name : String )
    {
        self.init();
        self.name = name;
    }

    public init() {
        run();
    }

    /**
     * run()/stop() accumulate time
     */
    public func run()
    {
        start=Time.now();
    }

    /**
     * run()/stop() accumulate time
     */
    public func stop()
    {
        elapsed += Time.now() - start;
        start = 0
    }

    public func ms() -> UInt64
    {
        if ( start == 0 ) {
            return elapsed;
        } else {
            return ( Time.now() - start ) + elapsed;
        }
    }
    public func s() -> Float
    {
        return Float(ms()) / 1000;
    }

    public class func now() -> UInt64 {
        //return System.currentTimeMillis();
        return UInt64( NSDate().timeIntervalSince1970*1000 )
    }
    
    public func gt( _ms : UInt64 ) -> Bool {
        return ms() > _ms ;
    }

    /**
     * Get a new Time instance that is the time divided over the number specified.
     * e.g. time.per( numUsers ) might represent the time consumed by each user operation.
     * @param num
     * @return
     */
    public func per( num : Int ) -> Time
    {
        return Time( ms() / UInt64(num) );
    }
    
    /**
    * e.g. given num iterations returns the rate in iterations per second.
    */
    public func rate( num: Int ) -> Float {
        return Float(num)/s()
    }

    public func toString() -> String
    {
        if ( ms() < 1000 ) {
            return "\(ms())ms"
        } else
        {
            return NSString( format: "%.1fs", s() ) as String
        }
    }

    public var description: String {
        return toString()
    }
}