BOF, EOF, and Bookmark Properties Example (VJ++)
This example uses the BOF and EOF properties to display a message if a user tries to move past the first or last record of a Recordset. It uses the Bookmark property to let the user flag a record in a Recordset and return to it later.
import com.ms.wfc.data.*;
import java.io.*;
import com.ms.com.*;
public class BOFEOFBookmark
{
Variant varBookmark;
BufferedReader in =
new BufferedReader(new InputStreamReader(System.in));
String line = null;
// The main entry point for the application.
public static void main (String[] args)
{
BOFEOFBookmark b1 = new BOFEOFBookmark ();
b1.BOFX();
b1.BOFX2();
System.exit(0);
try
{
b1.finalize();
}
catch(Throwable te)
{
}
}
// The main entry point for the application.
public void BOFX()
{
// Declarations.
Recordset rstPublishers = null;
String strCnn;
String strMessage;
int intCommand = 0;
strCnn = "Provider=sqloledb;Data Source=srv;"
+ "Initial Catalog=pubs;User Id=sa;Password=;";
try
{
// Open a recordset with data from Publishers table.
rstPublishers = new Recordset();
rstPublishers.setCursorType(AdoEnums.CursorType.STATIC );
rstPublishers.setCursorLocation(
AdoEnums.CursorLocation.CLIENT);
// Use client cursor to enable AbsolutePosition property.
rstPublishers.open(new String(
"SELECT pub_id,pub_name FROM Publishers ORDER BY pub_name"),
strCnn, AdoEnums.CursorType.STATIC ,
AdoEnums.LockType.BATCHOPTIMISTIC,
AdoEnums.CommandType.TEXT );
rstPublishers.moveFirst();
//Display information about current record and get user input.
while ( true)
{
strMessage = "\nPublisher :" +
rstPublishers.getField("pub_name").getString() + "\n"
+ " (Record " + rstPublishers.getAbsolutePosition()
+ " of " + rstPublishers.getRecordCount() + ")" + "\n\n"
+ "Enter command : " + "\n"
+ "[1 - next / 2 - previous /" + "\n"
+ "3 - set bookmark / 4 - go to bookmark]" ;
System.out.println (strMessage);
line = in.readLine();
//No entry exits loop.
if (line.length() == 0)
break;
//convert string entry to int.
intCommand = Integer.parseInt(line);
//out of range entry exits loop.
if ((intCommand < 1) || (intCommand > 4)) break ;
//Call method based on user's validated selection.
MoveAny(intCommand, rstPublishers);
}
rstPublishers.close();
}
catch( AdoException ae )
{
// Notify user of any errors that result from ADO.
// As passing a Recordset, check for null pointer first.
if (rstPublishers != null)
{
PrintProviderError(rstPublishers.getActiveConnection());
}
else
{
System.out.println("Exception: " + ae.getMessage());
}
}
// This catch is required if input string cannot be converted to
// Integer data type. "TCS[VSD]"
catch ( java.lang.NumberFormatException ne)
{
System.out.println("\nException: Integer Input required." );
}
// System Read requires this catch.
catch( java.io.IOException je )
{
PrintIOError(je);
}
}
// MoveAny Function
public void MoveAny(int intChoice, Recordset rsTemp)
{
// Move Forward or backword per selection from user,
// trapping for BOF and EOF.
try
{
switch(intChoice)
{
case 1: // Equals char of 1.
rsTemp.moveNext();
if (rsTemp.getEOF())
{
System.out.println (
"\nMoving past the last record \nTry again." );
rsTemp.moveLast();
}
break;
case 2: // Equals char of 2.
rsTemp.movePrevious();
if (rsTemp.getBOF())
{
System.out.println (
"\nMoving past the first record \nTry again." );
rsTemp.moveFirst();
}
break;
case 3: // Equals char of 3.
// Store the bookmark of the current record.
varBookmark = (Variant)rsTemp.getBookmark();
break;
case 4: // Equals char of 4.
// Go to the record indicated by the stored bookmark.
if (varBookmark == null)
System.out.println ("\nNo bookmark set!");
else
rsTemp.setBookmark((Object)varBookmark);
break;
default:
break;
}
}
catch( AdoException ae )
{
// Notify user of any errors that result from ADO.
// As passing a Recordset, check for null pointer first.
if (rsTemp != null)
{
PrintProviderError(rsTemp.getActiveConnection());
}
else
{
System.out.println("Exception: " + ae.getMessage());
}
}
}
// PrintProviderError Function
static void PrintProviderError( Connection Cnn1 )
{
// Print Provider errors from Connection object.
// ErrItem is an item object in the Connection’s 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");
}
////////////////////////////////////////////
// BOFX2() Function. //
////////////////////////////////////////////
public void BOFX2()
{
Recordset rs = null ;
try
{
// Declarations.
rs = new Recordset();
Variant[] arrbmk = new Variant[11];
rs.setCursorLocation( AdoEnums.CursorLocation.CLIENT);
String strCnn = "Provider=MSDASQL;Data Source=Pubs DSN;"
+ "Initial Catalog=pubs;User Id=sa;Password=;";
rs.setActiveConnection (strCnn);
// Open recorset with data from authors table.
rs.open((new String("SELECT * FROM authors")),strCnn,AdoEnums.CursorType.STATIC ,AdoEnums.LockType.BATCHOPTIMISTIC,AdoEnums.CommandType.TEXT );
System.out.println ("\nNumber of records before filtering : " + rs.getRecordCount() );
int ii = 0;
// Create array of bookmarks.
while (rs.getEOF() != true && ii < 11)
{
arrbmk[ii] = (Variant)rs.getBookmark();
ii++;
rs.move (2);
}
// set Filter to recordset.
Variant bmk=new Variant();
bmk.putVariantArray(arrbmk);
rs.setFilter(bmk);
System.out.println ("\nNumber of records after filtering : " + rs.getRecordCount() );
// Dislay the records after filtering.
rs.moveFirst();
while (!rs.getEOF())
{
System.out.println ("\t" +rs.getAbsolutePosition() + " " +rs.getField("au_lname").getString());
rs.moveNext();
}
rs.close();
System.out.println ("\n\nPress <Enter> key 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 (rs != null)
{
PrintProviderError(rs.getActiveConnection());
System.out.println("Exception: " + ae.getMessage());
}
else
{
System.out.println("Exception: " + ae.getMessage());
}
}
// System Read requires this catch.
catch( java.io.IOException je )
{
PrintIOError(je);
}
}
}