code: public long getDepth() throws SIMPControllableNotFoundException
    {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.entry(tc, "getDepth");
      //the number of tick ranges in the value state on the streams
      long depth=0;
      SIMPIterator iterator = this.getStreams();
      while(iterator.hasNext())
      {
        depth+=
          ((SourceStreamControl)iterator.next()).getNumberOfActiveMessages();
      }
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.exit(tc, "getDepth", new Long(depth));
      return depth;
    }
docs: /* (non-Javadoc)
  @see com.ibm.ws.sib.processor.runtime.SIMPDeliveryStreamSetTransmitControllable#getDepth