Count プロパティの例 (VJ++)

この例では、Employees データベース内の 2 つのコレクションで Count プロパティを使用します。このプロパティで、各コレクション内のオブジェクト数を取得し、これらのコレクションを列挙するループに上限を設定します。

import com.ms.wfc.data.*;
import java.io.* ;

public class CountX
{
    // The main entry point for the application.

    public static void main (String[] args)
    {
        CountX();
        System.exit(0);
    }

    // CountX function

    static void CountX()
    {

        // Define ADO Objects.
        Recordset rstEmployees = null;

        // Declarations.
        BufferedReader in =
            new BufferedReader (new InputStreamReader(System.in));
        String line = null;
        String strCnn = "Provider=sqloledb;Data Source=srv;"
            + "Initial Catalog=Pubs;User Id=sa;Password=;";

        int intLoop;
        int intDisplaySize = 20;
        int recCount=0;

        try
        {
            rstEmployees = new Recordset();

            // Open recordset with data from Employees table.
            rstEmployees.open("employee", strCnn,
                AdoEnums.CursorType.FORWARDONLY,
                AdoEnums.LockType.READONLY,
                AdoEnums.CommandType.TABLE);

            // Print information about Fields collection.
            System.out.println(rstEmployees.getFields().getCount() +
                " Fields in Employees");
            for ( intLoop = 0; intLoop <
                rstEmployees.getFields().getCount(); intLoop++)
            {
                System.out.println("\t" +
                    rstEmployees.getFields().getItem(intLoop).getName());
            }
            System.out.println("\n\nPress <Enter> to continue..");
            in.readLine();

            // Print information about Properties collection.
            System.out.println(rstEmployees.getProperties().getCount() +
                " Properties in Employees");
            for ( intLoop = 0; intLoop <
                rstEmployees.getProperties().getCount(); intLoop++)
            {
                System.out.println("\t" +
                    rstEmployees.getProperties().getItem(intLoop).getName());
                recCount++;
                if ( recCount >= intDisplaySize)
                {
                    System.out.println("\n\nPress <Enter> to continue..");
                    in.readLine();
                    recCount = 0;
                }
            }
            System.out.println("\n\nPress <Enter> to continue..");
            in.readLine();

            // Cleanup objects before exit.
            rstEmployees.close();

        }
        catch( AdoException ae )
        {
            // Notify user of any errors that result from ADO.

            // Check for null pointer for connection object.
            if (rstEmployees.getActiveConnection()==null)
            {
                System.out.println("Exception: " + ae.getMessage());
            }
            else
            {
                // As passing a Recordset, check for null pointer first.
                if (rstEmployees != null)
                {
                    PrintProviderError(rstEmployees.getActiveConnection());
                }
                else
                {
                    System.out.println("Exception: " + ae.getMessage());
                }
            }
        }

        // System read requires this catch.
        catch( java.io.IOException je)
        {
            PrintIOError(je);
        }
    }

    // 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");
    }
}