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JDBC Driver for the Firebird RDBMS
There is a newer version: 2.2.7
/*
 * $Id: FBCachedFetcher.java 60425 2014-12-24 11:02:41Z mrotteveel $
 *
 * Firebird Open Source JavaEE Connector - JDBC Driver
 *
 * Distributable under LGPL license.
 * You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * LGPL License for more details.
 *
 * This file was created by members of the firebird development team.
 * All individual contributions remain the Copyright (C) of those
 * individuals.  Contributors to this file are either listed here or
 * can be obtained from a source control history command.
 *
 * All rights reserved.
 */
package org.firebirdsql.jdbc;

import java.sql.*;
import java.util.ArrayList;

import org.firebirdsql.gds.GDSException;
import org.firebirdsql.gds.XSQLVAR;
import org.firebirdsql.gds.impl.AbstractIscStmtHandle;
import org.firebirdsql.gds.impl.GDSHelper;
import org.firebirdsql.jdbc.field.*;

class FBCachedFetcher implements FBFetcher {

    private final boolean forwardOnly;
    private Object[] rowsArray;
    private int rowNum = 0;

    private int fetchSize;
    
    private final FBObjectListener.FetcherListener fetcherListener;

    FBCachedFetcher(GDSHelper gdsHelper, int fetchSize, int maxRows, AbstractIscStmtHandle stmt_handle,
            FBObjectListener.FetcherListener fetcherListener, boolean forwardOnly) throws SQLException {
        this.fetcherListener = fetcherListener;
        this.forwardOnly = forwardOnly;
        final ArrayList rowsSets = new ArrayList(100);
        final XSQLVAR[] xsqlvars = stmt_handle.getOutSqlda().sqlvar;

        // Check if there is blobs to catch
        final boolean[] isBlob = new boolean[xsqlvars.length];
        boolean hasBlobs = false;
        for (int i = 0; i < xsqlvars.length; i++){
            isBlob[i] = FBField.isType(xsqlvars[i], Types.BLOB) ||
                FBField.isType(xsqlvars[i], Types.BINARY) ||
                FBField.isType(xsqlvars[i], Types.LONGVARCHAR);
            if (isBlob[i]) 
                hasBlobs = true;
        }
        
        // load all rows from statement
        int rowsCount = 0;
        try {
            if (fetchSize == 0)
                fetchSize = MAX_FETCH_ROWS;
            this.fetchSize = fetchSize;

            // the following if, is only for callable statement				
            if (!stmt_handle.isAllRowsFetched() && stmt_handle.size() == 0) {
                do {
                    if (maxRows != 0 && fetchSize > maxRows - rowsCount)
                        fetchSize = maxRows - rowsCount;
                    gdsHelper.fetch(stmt_handle, fetchSize);

                    final int fetchedRowCount = stmt_handle.size();
                    if (fetchedRowCount > 0){
                        byte[][][] rows = stmt_handle.getRows();
                        // Copy of right length when less rows fetched than requested
                        if (rows.length > fetchedRowCount) {
                            final byte[][][] tempRows = new byte[fetchedRowCount][][];
                            System.arraycopy(rows, 0, tempRows, 0, fetchedRowCount);
                            rows = tempRows;
                        }
                        rowsSets.add(rows);
                        rowsCount += fetchedRowCount;
                        stmt_handle.removeRows();
                    }
                } while (!stmt_handle.isAllRowsFetched() && (maxRows == 0 || rowsCount  rowsArray.length;
    }

    public void deleteRow() throws SQLException {
        final Object[] newRows = new Object[rowsArray.length - 1];
        System.arraycopy(rowsArray, 0, newRows, 0, rowNum - 1);
        
        if (rowNum < rowsArray.length)
            System.arraycopy(rowsArray, rowNum, newRows, rowNum - 1, rowsArray.length - rowNum);
        
        rowsArray = newRows;
        
        if (isAfterLast())
            fetcherListener.rowChanged(this, null);
        else
        if (isBeforeFirst())
            fetcherListener.rowChanged(this, null);
        else
            fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
    }

    public void insertRow(byte[][] data) throws SQLException {
        final Object[] newRows = new Object[rowsArray.length + 1];
        
        if (rowNum == 0)
            rowNum++;
        
        System.arraycopy(rowsArray, 0, newRows, 0, rowNum - 1);
        System.arraycopy(rowsArray, rowNum - 1, newRows, rowNum, rowsArray.length - rowNum + 1);
        newRows[rowNum - 1] = data;

        rowsArray = newRows;

        if (isAfterLast() || isBeforeFirst())
            fetcherListener.rowChanged(this, null);
        else
            fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
    }

    public void updateRow(byte[][] data) throws SQLException {
        if (!isAfterLast() && !isBeforeFirst()) {
            rowsArray[rowNum - 1] = data;
            fetcherListener.rowChanged(this, data);
        }
    }

    public int getFetchSize(){
        return fetchSize;
    }

    public void setFetchSize(int fetchSize){
        this.fetchSize = fetchSize;
    }
}