/*
* 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 Software Foundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.db.table;
import com.caucho.db.block.BlockStore;
import com.caucho.db.index.BTree;
import com.caucho.db.sql.QueryContext;
import com.caucho.db.xa.DbTransaction;
import com.caucho.sql.SQLExceptionWrapper;
import com.caucho.util.L10N;
import java.io.IOException;
import java.sql.SQLException;
/**
* Validity constraints.
*/
public class UniqueSingleColumnConstraint extends Constraint {
private final static L10N L = new L10N(UniqueSingleColumnConstraint.class);
private final Column _uniqueColumn;
/**
* Creates a uniqueness constraint.
*/
public UniqueSingleColumnConstraint(Column column)
{
_uniqueColumn = column;
}
/**
* validate the constraint.
*/
@Override
public void validate(TableIterator []sourceRows,
QueryContext queryContext, DbTransaction xa)
throws SQLException
{
Column column = _uniqueColumn;
BTree index = column.getIndex();
if (index != null) {
validateIndex(sourceRows, queryContext, xa);
return;
}
TableIterator sourceRow = sourceRows[0];
Table table = sourceRow.getTable();
TableIterator iter = table.createTableIterator();
try {
byte []sourceBuffer = sourceRow.getBuffer();
int sourceOffset = sourceRow.getRowOffset();
iter.init(queryContext);
while (iter.next()) {
byte []iterBuffer = iter.getBuffer();
iter.prevRow();
while (iter.nextRow()) {
int iterOffset = iter.getRowOffset();
if (iterBuffer == sourceBuffer && iterOffset == sourceOffset)
continue;
if (column.isEqual(iterBuffer, iterOffset,
sourceBuffer, sourceOffset)) {
long blockId = iter.getBlockId();
throw new SQLException(L.l("`{0}' in {1}.{2} fails uniqueness constraint.",
column.getString(blockId, iterBuffer, iterOffset),
table.getName(),
column.getName()));
}
}
}
} catch (IOException e) {
throw new SQLExceptionWrapper(e);
} finally {
iter.free();
}
}
/**
* validate the constraint.
*/
private void validateIndex(TableIterator []sourceRows,
QueryContext context, DbTransaction xa)
throws SQLException
{
try {
Column column = _uniqueColumn;
TableIterator sourceRow = sourceRows[0];
byte []sourceBuffer = sourceRow.getBuffer();
int sourceOffset = sourceRow.getRowOffset();
BTree index = column.getIndex();
/*
int length = column.evalToBuffer(sourceBuffer, sourceOffset,
buffer, 0);
if (length <= 0)
return;
long value = index.lookup(buffer, 0, length,
context.getTransaction());
*/
// currently this is a static length. See StringColumn.
int length = column.getLength();
int offset = sourceOffset + _uniqueColumn.getColumnOffset();
long value = index.lookup(sourceBuffer, offset, length);
if (value != 0) {
Table table = sourceRow.getTable();
long blockId = sourceRow.getBlockId();
throw new SQLException(L.l("'{0}' in {1}.{2} fails uniqueness constraint with block address {3}.",
column.getString(blockId,
sourceBuffer,
sourceOffset),
table.getName(),
column.getName(),
("" + (value / BlockStore.BLOCK_SIZE)
+ "." + (value % BlockStore.BLOCK_SIZE))));
}
} catch (IOException e) {
throw new SQLExceptionWrapper(e);
}
}
}