001/* 002 * HA-JDBC: High-Availability JDBC 003 * Copyright (c) 2004-2007 Paul Ferraro 004 * 005 * This library is free software; you can redistribute it and/or modify it 006 * under the terms of the GNU Lesser General Public License as published by the 007 * Free Software Foundation; either version 2.1 of the License, or (at your 008 * option) any later version. 009 * 010 * This library is distributed in the hope that it will be useful, but WITHOUT 011 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 012 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License 013 * for more details. 014 * 015 * You should have received a copy of the GNU Lesser General Public License 016 * along with this library; if not, write to the Free Software Foundation, 017 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 018 * 019 * Contact: ferraro@users.sourceforge.net 020 */ 021package net.sf.hajdbc.local; 022 023import java.util.HashMap; 024import java.util.Map; 025import java.util.concurrent.TimeUnit; 026import java.util.concurrent.locks.Condition; 027import java.util.concurrent.locks.Lock; 028import java.util.concurrent.locks.ReadWriteLock; 029 030import net.sf.hajdbc.LockManager; 031import net.sf.hajdbc.util.concurrent.SemaphoreReadWriteLock; 032 033/** 034 * @author Paul Ferraro 035 */ 036public class LocalLockManager implements LockManager 037{ 038 private Map<String, ReadWriteLock> lockMap = new HashMap<String, ReadWriteLock>(); 039 040 /** 041 * @see net.sf.hajdbc.LockManager#readLock(java.lang.String) 042 */ 043 @Override 044 public Lock readLock(String object) 045 { 046 Lock lock = this.getReadWriteLock(null).readLock(); 047 048 return (object == null) ? lock : new GlobalLock(lock, this.getReadWriteLock(object).readLock()); 049 } 050 051 /** 052 * @see net.sf.hajdbc.LockManager#writeLock(java.lang.String) 053 */ 054 @Override 055 public Lock writeLock(String object) 056 { 057 ReadWriteLock readWriteLock = this.getReadWriteLock(null); 058 059 return (object == null) ? readWriteLock.writeLock() : new GlobalLock(readWriteLock.readLock(), this.getReadWriteLock(object).writeLock()); 060 } 061 062 private synchronized ReadWriteLock getReadWriteLock(String object) 063 { 064 ReadWriteLock lock = this.lockMap.get(object); 065 066 if (lock == null) 067 { 068 lock = new SemaphoreReadWriteLock(true); 069 070 this.lockMap.put(object, lock); 071 } 072 073 return lock; 074 } 075 076 private static class GlobalLock implements Lock 077 { 078 private Lock globalLock; 079 private Lock lock; 080 081 GlobalLock(Lock globalLock, Lock lock) 082 { 083 this.globalLock = globalLock; 084 this.lock = lock; 085 } 086 087 @Override 088 public void lock() 089 { 090 this.globalLock.lock(); 091 this.lock.lock(); 092 } 093 094 @Override 095 public void lockInterruptibly() throws InterruptedException 096 { 097 this.globalLock.lockInterruptibly(); 098 099 try 100 { 101 this.lock.lockInterruptibly(); 102 } 103 catch (InterruptedException e) 104 { 105 this.globalLock.unlock(); 106 throw e; 107 } 108 } 109 110 @Override 111 public boolean tryLock() 112 { 113 if (this.globalLock.tryLock()) 114 { 115 if (this.lock.tryLock()) 116 { 117 return true; 118 } 119 120 this.globalLock.unlock(); 121 } 122 123 return false; 124 } 125 126 @Override 127 public boolean tryLock(long time, TimeUnit unit) throws InterruptedException 128 { 129 if (this.globalLock.tryLock(time, unit)) 130 { 131 if (this.lock.tryLock(time, unit)) 132 { 133 return true; 134 } 135 136 this.globalLock.unlock(); 137 } 138 139 return false; 140 } 141 142 @Override 143 public void unlock() 144 { 145 this.lock.unlock(); 146 this.globalLock.unlock(); 147 } 148 149 @Override 150 public Condition newCondition() 151 { 152 throw new UnsupportedOperationException(); 153 } 154 } 155 156 /** 157 * @see net.sf.hajdbc.Lifecycle#start() 158 */ 159 @Override 160 public void start() throws Exception 161 { 162 // Do nothing 163 } 164 165 /** 166 * @see net.sf.hajdbc.Lifecycle#stop() 167 */ 168 @Override 169 public void stop() 170 { 171 // Do nothing 172 } 173}