/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hp.hpl.jena.tdb.migrate;
import com.hp.hpl.jena.query.ReadWrite ;
import com.hp.hpl.jena.shared.Lock ;
import com.hp.hpl.jena.tdb.transaction.DatasetGraphTransaction ;
import com.hp.hpl.jena.tdb.transaction.TDBTransactionException ;
import static com.hp.hpl.jena.tdb.migrate.LockTx.LockTxState.* ;
/** Lock that provides transactions
* Not reentrant.
*/
public class LockTx implements Lock
{
private DatasetGraphTransaction dsg ;
public LockTx(DatasetGraphTransaction dsg) { this.dsg = dsg ; }
static enum LockTxState { TxNONE, TxREAD, TxWRITE }
private LockTxState state = TxNONE ;
@Override
public void enterCriticalSection(boolean readLockRequested)
{
if ( state != TxNONE )
throw new TDBTransactionException("Illegal state: "+state) ;
if ( readLockRequested )
{
state = TxREAD ;
dsg.begin(ReadWrite.READ) ;
}
else
{
state = TxWRITE ;
dsg.begin(ReadWrite.WRITE) ;
}
}
@Override
public void leaveCriticalSection()
{
switch (state)
{
case TxNONE : throw new TDBTransactionException("Illegal state: "+state) ;
case TxREAD : dsg.close() ; break ;
case TxWRITE : dsg.commit() ; break ;
}
state = TxNONE ;
}
}