/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source 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, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.db.sql;
import java.sql.SQLException;
import com.caucho.db.block.BlockStore;
import com.caucho.db.jdbc.GeneratedKeysResultSet;
import com.caucho.db.table.Column;
import com.caucho.db.table.Table;
import com.caucho.db.table.TableIterator;
class IdentityExpr extends Expr {
private Table _table;
private Column _column;
IdentityExpr(Table table, Column column)
{
_table = table;
_column = column;
}
/**
* Returns the type of the expression.
*/
@Override
public Class<?> getType()
{
return long.class;
}
/**
* Evaluates the expression as a long
*
* @param row the current data tuple
*
* @return the long value
*/
@Override
public long evalLong(QueryContext context)
throws SQLException
{
GeneratedKeysResultSet keysRS = context.getGeneratedKeysResultSet();
final TableIterator []rows = context.getTableIterators();
final TableIterator row = rows[0];
long value = (row.getBlockId() & BlockStore.BLOCK_MASK) + row.getRowOffset();
if (keysRS != null) {
keysRS.setColumn(1, _column);
keysRS.setLong(1, value);
}
return value;
}
/**
* Evaluates the expression as a double
*
* @param row the current data tuple
*
* @return the double value
*/
@Override
public double evalDouble(QueryContext context)
throws SQLException
{
return evalLong(context);
}
/**
* Evaluates the expression as a string
*
* @param row the current data tuple
*
* @return the string value
*/
@Override
public String evalString(QueryContext context)
throws SQLException
{
return String.valueOf(evalLong(context));
}
@Override
public String toString()
{
return "identity()";
}
}