code: @Override
  	public Object evaluate( Message message ) throws JMSException
      {
          Boolean leftOperandValue = leftOperand.evaluateBoolean(message);
          if (leftOperandValue == null)
          {
              Boolean rightOperandValue = rightOperand.evaluateBoolean(message);
              if (rightOperandValue == null || !rightOperandValue.booleanValue())
                  return null;
              
              return Boolean.TRUE;
          }
          else
          {
              if (leftOperandValue.booleanValue())
                  return Boolean.TRUE;
              
              return rightOperand.evaluateBoolean(message);
          }
      }
docs: /*
  (non-Javadoc)
  @see net.timewalker.ffmq4.common.message.selector.expression.SelectorNode#evaluate(javax.jms.Message)