public class SemaphoreGroup
{
    private int[] values;

    public SemaphoreGroup(int numberOfMembers)
    {
        if(numberOfMembers <= 0)
            return;
        values = new int[numberOfMembers];
    }

    public int getNumberOfMembers()
    {
        return values.length;
    }

    public synchronized void changeValues(int[] deltas)
    {
        if(deltas.length != values.length)
            return;
        while(!canChange(deltas))
        {
            try
            {
                wait();
            }
            catch(InterruptedException e)
            {
            }
        }
        doChange(deltas);
        notifyAll();
    }

    private boolean canChange(int[] deltas)
    {
        for(int i = 0; i < values.length; i++)
            if(values[i] + deltas[i] < 0)
                return false;
        return true;
    }

    private void doChange(int[] deltas)
    {
        for(int i = 0; i < values.length; i++)
            values[i] = values[i] + deltas[i];
    }
}