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annotate src/org/dancres/blitz/txnlock/LockMgr.java @ 0:3dc0c5604566

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Initial checkin of blitz 2.0 fcs - no installer yet.
author Dan Creswell <dan.creswell@gmail.com>
date Sat, 21 Mar 2009 11:00:06 +0000
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3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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1 package org.dancres.blitz.txnlock;
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2
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Dan Creswell <dan.creswell@gmail.com>
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3 import org.dancres.blitz.oid.OID;
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4
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Dan Creswell <dan.creswell@gmail.com>
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5 /**
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Dan Creswell <dan.creswell@gmail.com>
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6 A lock mgr instance is responsible for tracking all transaction locks
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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7 for a particular Entry type.
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Dan Creswell <dan.creswell@gmail.com>
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8 */
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9 public class LockMgr {
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Dan Creswell <dan.creswell@gmail.com>
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10 /**
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Dan Creswell <dan.creswell@gmail.com>
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11 For as long as any transaction has a reference to the lock, it will
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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12 be maintained by the LockMgr. Obviously, if there are no pending
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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13 transactions there's no need to hold the lock or it's state because
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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14 the lock should be clear. If it's not clear, we have a bug!!!! :)
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15 */
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16 // private SoftHashMap theLocks = new SoftHashMap();
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17 private LockCache theLocks = new LockCache();
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18
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19 public TxnLock getLock(OID aOID) {
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20 return theLocks.getOrInsert(aOID);
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Dan Creswell <dan.creswell@gmail.com>
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21 }
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22
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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23 public TxnLock newLock(OID aOID) {
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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24 TxnLock myLock = new TxnLock();
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25
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26 theLocks.put(aOID, myLock);
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27
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28 return myLock;
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Dan Creswell <dan.creswell@gmail.com>
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29 }
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Dan Creswell <dan.creswell@gmail.com>
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31 /**
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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32 Test to see if the specified OID has an active lock associated
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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33 with it. This is only truly useful in situations where the associated
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34 Entry is in an unchanging state perhaps because it has been DELETED
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35 or it's lease has expired.
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36 */
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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37 public boolean hasActiveLock(OID aOID) {
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38 TxnLock myLock = (TxnLock) theLocks.get(aOID);
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39
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40 if (myLock != null) {
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41 synchronized(myLock) {
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42 return myLock.isActive();
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43 }
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44 }
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45
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46 return false;
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47 }
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49 }