| /* |
| * 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 org.apache.directory.mavibot.btree; |
| |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.apache.directory.mavibot.btree.exception.BadTransactionStateException; |
| |
| /** |
| * A data structure used to manage a write transaction |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| /* no qualifier */ class WriteTransaction |
| { |
| /** A lock used to protect the write operation against concurrent access */ |
| protected ReentrantLock writeLock; |
| |
| /* no qualifier */WriteTransaction() |
| { |
| //System.out.println( "Creating the transaction oject" ); |
| writeLock = new ReentrantLock(); |
| } |
| |
| |
| /* no qualifier */ void start() |
| { |
| /* |
| if ( writeLock.isLocked() ) |
| { |
| throw new BadTransactionStateException( "Cannot start a write transaction when it's already started" ); |
| } |
| */ |
| |
| //System.out.println( "Start a TXN [" + Thread.currentThread().getName() + "]" ); |
| |
| writeLock.lock(); |
| //System.out.println( "WriteTransaction " + Thread.currentThread().getName() ); |
| } |
| |
| |
| /* no qualifier */ void commit() |
| { |
| if ( !writeLock.isLocked() ) |
| { |
| throw new BadTransactionStateException( "Cannot commit a write transaction when it's not started" ); |
| } |
| |
| //System.out.println( "Commit a TXN[" + Thread.currentThread().getName() + "]" ); |
| |
| writeLock.unlock(); |
| } |
| |
| |
| /* no qualifier */ void rollback() |
| { |
| if ( !writeLock.isLocked() ) |
| { |
| throw new BadTransactionStateException( "Cannot commit a write transaction when it's not started" ); |
| } |
| |
| //System.out.println( "Rollback a TXN" ); |
| writeLock.unlock(); |
| } |
| |
| |
| /** |
| * Tells if the transaction has started |
| * @return true if the transaction has started |
| */ |
| /* no qualifier */ boolean isStarted() |
| { |
| return writeLock.isLocked(); |
| } |
| } |