Hi Michael.  MASON doesn't have these built-in, but the following  

should do the trick.  This is a place where Bag significantly  

outperforms ArrayList.  Note that if you're using ParallelSequence or  

AsynchronousSteppable, you don't want to add objects to the list from  

within those threads as it'd create a race condition that's not  

checked for in the code below.



Sean



public class ExpandableSequence implements Steppable

	{

	public Bag steps;



	public ExpandableSequence(Bag steps) { this.steps = steps; }

	public ExpandableSequence() { this.steps = new Bag(); }

	public ExpandableSequence(Steppable[] steps) { this.steps = new Bag 

(steps); }

	public void step(SimState state)

		{

		for(int x=0;x<steps.numObjs; x++)

			((Steppable)(steps.objs[x])).step(state);

		}

	}





public class RandomExpandableSequence extends ExpandableSequence

	{

	public RandomExpandableSequence(Bag steps) { super(steps); }

	public RandomExpandableSequence() { super(); }

	public RandomExpandableSequence(Steppable[] steps) { super(steps); }



	public void step(SimState state)

		{

		synchronized(state.random)

			{ steps.shuffle(state.random); }

		super.step(state);

		}

	}





On Apr 4, 2006, at 11:04 AM, Michael Lees wrote:



> Hi,

>

> This is my first post to the list, I've been using mason for a few  

> weeks now.

>

> I'm using the Sequence class but have found the steps array  

> inflexible in terms of adding new Steppables during execution.

>

> I've implemented an ExpandableSequence which uses an arrayList  

> rather than an array. I was wondering if something already exists  

> for this? I might use RandomSequence at some point, which would  

> mean re-implementing RandomSequence to extend ExpandableSequence.