CompareBookmarks, méthode – Exemple (VJ++)

S’applique à : Access 2013, Office 2013

Cet exemple illustre le fonctionnement de la méthode CompareBookmarks. La valeur relative des signets est rarement requise sauf si un signet particulier présente une caractéristique spéciale.

Désignez une ligne aléatoire d’un objet Recordset dérivé de la table Authors comme cible d’une recherche. Affichez ensuite la position de chaque ligne par rapport à cette cible.

 
// BeginCompareBookmarksJ 
import com.ms.wfc.data.*; 
import java.io.* ; 
import com.ms.com.*; 
 
public class CompareBookmarksX // 
{ 
 // The main entry point for the application. 
 
 public static void main (String[] args) 
 { 
 CompareBookmarksX(); 
 System.exit(0); 
 } 
 
 // CompareBookmarksX function 
 
 static void CompareBookmarksX() 
 { 
 // Define ADO Objects. 
 Recordset rstAuthors = null; 
 
 // Declarations. 
 BufferedReader in = 
 new BufferedReader (new InputStreamReader(System.in)); 
 String strCnn = "Provider='sqloledb';Data Source='MySqlServer';" + 
 "Initial Catalog='Pubs';Integrated Security='SSPI';"; 
 int intCount; 
 Variant varTarget = null; 
 int intResult; 
 String strAns; 
 int intDisplaySize = 15; 
 
 try 
 { 
 rstAuthors = new Recordset(); 
 rstAuthors.open("SELECT * FROM authors", 
 strCnn, 
 AdoEnums.CursorType.STATIC, 
 AdoEnums.LockType.READONLY, 
 AdoEnums.CommandType.TEXT); 
 intCount = rstAuthors.getRecordCount(); 
 System.out.println("Rows in the Recordset = " + 
 Integer.toString(intCount)); 
 
 // Exit if an empty recordset. 
 if(intCount == 0) 
 System.exit(0); 
 
 // Randomize. 
 intCount = (int)(intCount * Math.random()); 
 // Get position between 0 and count-1. 
 System.out.println("\nRandomly chosen row position = " + 
 Integer.toString(intCount)+ "\n"); 
 rstAuthors.move(intCount,new Integer(AdoEnums.Bookmark.FIRST)); // Move row to random position. 
 varTarget = (Variant)rstAuthors.getBookmark(); 
 // Remember the mystery row. 
 intCount = 0; 
 rstAuthors.moveFirst(); 
 
 // Loop through recordset. 
 while(!rstAuthors.getEOF()) 
 { 
 intResult = rstAuthors.compareBookmarks 
 ((Variant)rstAuthors.getBookmark(), varTarget); 
 if(intResult == AdoEnums.Compare.NOTEQUAL) 
 System.out.println("Row " + 
 Integer.toString(intCount) + 
 ": Bookmarks are not equal."); 
 else if(intResult == AdoEnums.Compare.NOTCOMPARABLE) 
 System.out.println("Row " + 
 Integer.toString(intCount) + 
 ": Bookmarks are not comparable."); 
 else 
 { 
 switch(intResult) 
 { 
 case AdoEnums.Compare.LESSTHAN : 
 strAns = "less than"; 
 break; 
 case AdoEnums.Compare.EQUAL : 
 strAns = "equal to"; 
 break; 
 case AdoEnums.Compare.GREATERTHAN : 
 strAns = "greater than"; 
 break; 
 default : 
 strAns = "in error comparing to"; 
 break; 
 } 
 System.out.println("Row position " + 
 Integer.toString(intCount) + 
 " is " + strAns + " the target."); 
 } 
 if(intCount % intDisplaySize == 0 && intCount > 0) 
 { 
 System.out.println("\nPress <Enter> to continue.."); 
 in.readLine(); 
 } 
 intCount++; 
 rstAuthors.moveNext(); 
 } 
 
 System.out.println("\nPress <Enter> to continue.."); 
 in.readLine(); 
 } 
 catch( AdoException ae ) 
 { 
 // Notify user of any errors that result from ADO. 
 
 // As passing a Recordset, check for null pointer first. 
 if (rstAuthors != null) 
 { 
 PrintProviderError(rstAuthors.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 (rstAuthors != null) 
 if (rstAuthors.getState() == 1) 
 rstAuthors.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"); 
 } 
} 
 
// EndCompareBookmarksJ