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JDBC Driver for the Firebird RDBMS
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 boolean forwardOnly;
private Object[] rowsArray;
private int rowNum = 0;
private int fetchSize;
private 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;
ArrayList rowsSets = new ArrayList(100);
AbstractIscStmtHandle stmt = stmt_handle;
byte[][] localRow = null;
XSQLVAR[] xsqlvars = stmt_handle.getOutSqlda().sqlvar;
//
// Check if there is blobs to catch
//
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.isAllRowsFetched() && stmt.size() == 0) {
do {
if (maxRows != 0 && fetchSize > maxRows - stmt.size())
fetchSize = maxRows - stmt.size();
gdsHelper.fetch(stmt, fetchSize);
if (stmt.size() > 0){
rowsSets.add(stmt.getRows());
rowsCount += stmt.size();
stmt.removeRows();
}
} while (!stmt.isAllRowsFetched() && (maxRows==0 || rowsCount rowsCount-rowCount){
System.arraycopy(oneSet, 0, rowsArray, rowCount, rowsCount-rowCount);
rowCount = rowsCount;
}
else{
System.arraycopy(oneSet, 0, rowsArray, rowCount, oneSet.length);
rowCount += oneSet.length;
}
}
rowsSets.clear();
}
else {
rowsArray = stmt.getRows();
stmt.removeRows();
}
//
if (hasBlobs){
for (int i=0;i< rowsArray.length; i++){
localRow = (byte[][])rowsArray[i];
//ugly blob caching workaround.
for (int j = 0; j < localRow.length; j++){
// if field is blob and there is a value in cache
if (isBlob[j] && localRow[j] != null ) {
// anonymous implementation of the FieldDataProvider interface
final byte[] tempData = localRow[j];
FieldDataProvider dataProvider = new FieldDataProvider() {
public byte[] getFieldData() {
return tempData;
}
public void setFieldData(byte[] data) {
throw new UnsupportedOperationException();
}
};
// copy data from current row
FBField localField = FBField.createField(
xsqlvars[j], dataProvider, gdsHelper, false);
FBFlushableField blob = (FBFlushableField)localField;
localRow[j] = blob.getCachedData();
}
}
}
}
gdsHelper.closeStatement(stmt, false);
}
catch (GDSException ge) {
throw new FBSQLException(ge);
}
}
FBCachedFetcher(ArrayList rows, FBObjectListener.FetcherListener fetcherListener) throws SQLException {
rowsArray = rows.toArray();
this.fetcherListener = fetcherListener;
}
public boolean next() throws SQLException {
if (isEmpty())
return false;
rowNum++;
if (isAfterLast()) {
fetcherListener.rowChanged(this, null);
// keep cursor right after last row
rowNum = rowsArray.length + 1;
return false;
}
fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
return true;
}
public boolean previous() throws SQLException {
if (forwardOnly)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
if (isEmpty())
return false;
rowNum--;
if(isBeforeFirst()) {
fetcherListener.rowChanged(this, null);
// keep cursor right before the first row
rowNum = 0;
return false;
}
fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
return true;
}
public boolean absolute(int row) throws SQLException {
if (forwardOnly)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
return absolute(row, false);
}
private boolean absolute(int row, boolean internal) throws SQLException {
if (forwardOnly && !internal)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
if (row < 0)
row = rowsArray.length + row + 1;
if (row == 0 && !internal)
throw new FBSQLException(
"You cannot position to the row 0 with absolute() method.");
if (isEmpty())
return false;
rowNum = row;
if(isBeforeFirst()) {
fetcherListener.rowChanged(this, null);
// keep cursor right before the first row
rowNum = 0;
return false;
}
if (isAfterLast()) {
fetcherListener.rowChanged(this, null);
rowNum = rowsArray.length + 1;
return false;
}
fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
return true;
}
public boolean first() throws SQLException {
if (forwardOnly)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
return absolute(1, true);
}
public boolean last() throws SQLException {
if (forwardOnly)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
return absolute(-1, true);
}
public boolean relative(int row) throws SQLException {
if (forwardOnly)
throw new FBDriverNotCapableException(
"Result set is TYPE_FORWARD_ONLY");
return absolute(rowNum + row, true);
}
public void beforeFirst() throws SQLException {
first();
previous();
}
public void afterLast() throws SQLException {
last();
next();
}
public void close() throws SQLException {
rowsArray = new Object[0];
}
public int getRowNum() {
return rowNum;
}
public boolean isEmpty() {
return rowsArray == null || rowsArray.length == 0;
}
public boolean isBeforeFirst() {
return !isEmpty() && rowNum < 1;
}
public boolean isFirst() {
return rowNum == 1;
}
public boolean isLast() {
return rowsArray != null ? rowNum == rowsArray.length : false;
}
public boolean isAfterLast() {
return rowNum > rowsArray.length;
}
/* (non-Javadoc)
* @see org.firebirdsql.jdbc.FBFetcher#deleteRow()
*/
public void deleteRow() throws SQLException {
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]);
}
/* (non-Javadoc)
* @see org.firebirdsql.jdbc.FBFetcher#insertRow(byte[][])
*/
public void insertRow(byte[][] data) throws SQLException {
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())
fetcherListener.rowChanged(this, null);
else
if (isBeforeFirst())
fetcherListener.rowChanged(this, null);
else
fetcherListener.rowChanged(this, (byte[][])rowsArray[rowNum-1]);
}
/* (non-Javadoc)
* @see org.firebirdsql.jdbc.FBFetcher#updateRow(byte[][])
*/
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;
}
}