What are the SCEX and SCEX Loan Server?

As mentioned in the Calculation Engine section of our web site, Sherman and Associates can provide you with the Sherman Calculation Engine with XML interface, hereafter called the SCEX. This calculation engine is a group of DLLs for the 32 bit Windows environment (98, Me, 2000, XP, 2003), and includes the needed documentation for implementation and XML data format.

Before the SCEX was created, there was its predecessor � the SCE. The SCE is a standard Windows DLL with documentation detailing the required function calls, complex data structures, result codes, etc. Shortly after the release of the SCE, we noticed a few shortcomings of the calculation engine.

By directly accessing the SCE, the user is faced with three problems:

Initially, the user of the SCE needs to implement all of the complex data structures used by the SCE for input and output, as well as create the interface to the functions found in the DLL.
As the SCE is modified to suit customer needs and federal or state regulations, these data structures may need to be altered. If you access the SCE directly, then the data structures which you create in the calling application's language must also be modified. Then, all applications which call the SCE must be recompiled.
Finally, what if you want to access the functionality of the SCE, but your application is not written for the 32 bit Windows platform? There is no simple way to access a 32 bit Windows DLL from another platform.

These three problems prompted Sherman and Associates to begin development on two new satellite projects of the SCE: the SCE with XML interface (hereafter called the SCEX) and the SCEX Loan Server.

The SCEX

The SCEX addresses problems one and two in the list above. It provides an XML interface wrapped around the SCE. By using the SCEX instead of the SCE, the calling application no longer needs to duplicate the data structures used by the SCE. Instead, all input sent to the SCEX is contained in one character buffer (or character string). Similarly, the SCEX returns all results in a single character buffer, which the calling application must provide.

The format of the text contained in these character buffers is what the ‘X’ in the SCEX is all about - XML. XML is a simple, flexible text format which is playing an increasingly important role in the exchange of data between disparate platforms and systems.

The SCEX alleviates the first problem by eliminating complex input and output data structures altogether. Instead, the application calling the SCEX provides the necessary input in a character buffer, which contains the XML data. As an example, here is the XML input data for a 36 month equal payment loan based on a 10% interest rate and $10,000:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE inEQUAL_PMT SYSTEM "inEQUAL_PMT.dtd" >
<inEQUAL_PMT Account="2" ForceReload="false" HOEPA="no" HideAmort="true" PPY="monthly">
 <LoanDate>2004-06-10</LoanDate>
 <PmtDate>2004-07-10</PmtDate>
 <IntRate>10.000%</IntRate>
 <Proceeds>$10,000.00</Proceeds>
 <Term>36</Term>
</inEQUAL_PMT>

The result of the loan calculation is then passed back to the calling application in a buffer. The application then need only parse the returned XML to use the calculation results as appropriate. Here is a sample result returned from the SCE, using the inputs specified above (with the amortization table turned off):

<?xml version="1.0" standalone="no" ?>
<!DOCTYPE outEQUAL_PMT  SYSTEM "outEQUAL_PMT.dtd" >
<outEQUAL_PMT>
 <Results>
  <Description>Successful Calculation</Description>
  <XMLDetail>XML Input is well formed</XMLDetail>
  <XMLDetail>XML Input is Valid.</XMLDetail>
  <XMLDetail>XML Output is untested</XMLDetail>
  <Payment>322.70</Payment>
  <Final>322.63</Final>
 </Results>
 <FedBox>
  <AmtFin>10000.00</AmtFin>
  <FinChg>1617.13</FinChg>
  <TotPmts>11617.13</TotPmts>
  <RegZAPR Type="Actuarial">10.006</RegZAPR>
 </FedBox>
 <Moneys>
  <Principal>10000.00</Principal>
  <Interest>1617.13</Interest>
  <Protection Category="None" PerPmt="0.00" PerDay="0.00">0.00</Protection>
 </Moneys>
 <Accrual>
  <Method>Actual/365 US Rule</Method>
  <Days1Pmt DayCount="Actual">30</Days1Pmt>
  <Maturity>2007-06-10</Maturity>
 </Accrual>
 <PmtStream Term="35" Pmt="322.70" Rate="10.000" Begin="2004-07-10"/>
 <PmtStream Term="1" Pmt="322.63" Rate="10.000" Begin="2007-06-10"/>
</outEQUAL_PMT>

Furthermore, the second problem mentioned above is also handled. If a new input or output data field is added to the SCE, then the appropriate XML input / output tags will be added to the SCEX. Applications which do not require this new functionality will NOT need to be recompiled. Instead, they will simply not provide the new input field, or not recognize the new output field. So long as your application does not require the use of the new data fields, then no recompilation is necessary!

The SCEX Loan Server

The SCEX Loan Server goes one step beyond the SCEX, turning the SCEX into a multi-platform calculation engine, thereby addressing problem three mentioned above. The SCEX Loan Server provides a TCP/IP communication wrapper around the SCEX. So long as the platform on which your application resides can communicate via TCP/IP, you can use the Sherman Calculation Engine in your product.

The SCEX Loan Server is a 32 bit Windows executable, or a 32 bit Windows 2000 / XP / 2003 service. The Loan Server listens on a specified port for incoming loan calculation requests. When it receives a loan request, the Loan Server dispatches the SCEX XML loan request to the SCEX. Once the SCEX returns an XML result to the SCEX Loan Server, the Loan Server then returns the XML result buffer to the client via TCP/IP.

Try Out the SCEX and Loan Server Now!