Ejemplo de la propiedad CacheSize (VJ++)

Se aplica a: Access 2013, Office 2013

En este ejemplo se utiliza la propiedad CacheSize para mostrar la diferencia en términos de rendimiento entre una operación realizada con una memoria caché de 30 registros y una operación realizada sin caché.

 
// BeginCacheSizeJ 
import com.ms.wfc.data.*; 
import java.io.* ; 
 
public class CacheSizeX 
{ 
 // The main entry point for the application. 
 
 public static void main (String[] args) 
 { 
 CacheSizeX(); 
 System.exit(0); 
 } 
 
 // CacheSizeX function 
 
 static void CacheSizeX() 
 { 
 
 // Define ADO Objects. 
 Recordset rstRoySched = null; 
 
 // Declarations. 
 BufferedReader in = 
 new BufferedReader (new InputStreamReader(System.in)); 
 String line = null; 
 String strCnn = "Provider='sqloledb';Data Source='MySqlServer';" 
 + "Initial Catalog='Pubs';Integrated Security='SSPI';"; 
 
 long timeStart; 
 long timeEnd; 
 float timeNoCache; 
 float timeCache; 
 int intLoop; 
 String strTemp; 
 
 try 
 { 
 // Open the RoySched table. 
 rstRoySched = new Recordset(); 
 rstRoySched.open("roysched", strCnn, 
 AdoEnums.CursorType.FORWARDONLY, 
 AdoEnums.LockType.READONLY, 
 AdoEnums.CommandType.TABLE); 
 
 // Enumerate the Recordset object twice and record 
 // the elapsed time. 
 
 timeStart = System.currentTimeMillis(); 
 for ( intLoop = 0; intLoop < 2; intLoop++) 
 { 
 rstRoySched.moveFirst(); 
 while (!rstRoySched.getEOF()) 
 { 
 // Execute a simple operation for the 
 // performance test. 
 strTemp = rstRoySched.getField("title_id").getString(); 
 rstRoySched.moveNext(); 
 } 
 
 } 
 
 timeEnd = System.currentTimeMillis(); 
 timeNoCache =(float)(timeEnd - timeStart)/1000f; 
 
 // Cache records in groups of 30 records. 
 rstRoySched.moveFirst(); 
 rstRoySched.setCacheSize(30); 
 timeStart = System.currentTimeMillis(); 
 
 // Enumerate the Recordset object twice and record 
 // the elapsed time. 
 for ( intLoop = 0; intLoop < 2; intLoop++) 
 { 
 rstRoySched.moveFirst(); 
 while (!rstRoySched.getEOF()) 
 { 
 // Execute a simple operation for the 
 // performance test. 
 
 strTemp = rstRoySched.getField("title_id").getString(); 
 rstRoySched.moveNext(); 
 } 
 
 } 
 
 timeEnd = System.currentTimeMillis(); 
 timeCache = (float)(timeEnd - timeStart)/1000f; 
 
 // Display performance results. 
 System.out.println("\nCaching Performance Results:"); 
 System.out.println("\n\tNo Cache: " + timeNoCache + " seconds"); 
 System.out.println("\n\t30-record cache: " + timeCache + 
 " seconds"); 
 System.out.println("\n\nPress <Enter> to continue.."); 
 in.readLine(); 
 
 } 
 catch( AdoException ae ) 
 { 
 // Notify user of any errors that result from ADO. 
 
 // Check for null pointer for connection object. 
 if (rstRoySched.getActiveConnection()==null) 
 System.out.println("Exception: " + ae.getMessage()); 
 
 // As passing a Recordset, check for null pointer first. 
 if (rstRoySched != null) 
 { 
 PrintProviderError(rstRoySched.getActiveConnection()); 
 } 
 else 
 { 
 System.out.println("Exception: " + ae.getMessage()); 
 } 
 } 
 
 // System read requires this catch. 
 catch( java.io.IOException je) 
 { 
 PrintIOError(je); 
 } 
 finally 
 { 
 // Cleanup objects before exit. 
 if (rstRoySched != null) 
 if (rstRoySched.getState() == 1) 
 rstRoySched.close(); 
 } 
 
 } 
 
 // PrintProviderError Function 
 
 static void PrintProviderError( Connection Cnn1 ) 
 { 
 // Print Provider errors from Connection object. 
 // ErrItem is an item object in the Connections Errors collection. 
 com.ms.wfc.data.Error ErrItem = null; 
 long nCount = 0; 
 int i = 0; 
 
 nCount = Cnn1.getErrors().getCount(); 
 
 // If there are any errors in the collection, print them. 
 if( nCount > 0); 
 { 
 // Collection ranges from 0 to nCount - 1 
 for (i = 0; i< nCount; i++) 
 { 
 ErrItem = Cnn1.getErrors().getItem(i); 
 System.out.println("\t Error number: " + ErrItem.getNumber() 
 + "\t" + ErrItem.getDescription() ); 
 } 
 } 
 
 } 
 
 // PrintIOError Function 
 
 static void PrintIOError( java.io.IOException je) 
 { 
 System.out.println("Error \n"); 
 System.out.println("\tSource = " + je.getClass() + "\n"); 
 System.out.println("\tDescription = " + je.getMessage() + "\n"); 
 } 
} 
 
// EndCacheSizeJ