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package net.sf.basedb.reggie; |
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import java.util.concurrent.TimeUnit; |
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import java.util.concurrent.locks.ReentrantLock; |
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import net.sf.basedb.core.DbControl; |
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import net.sf.basedb.core.TransactionalAction; |
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/** |
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Utility functions for locking. |
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@since 2.16 |
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*/ |
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public class LockUtil |
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implements TransactionalAction |
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{ |
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/** |
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Try to acquire the given lock for as long as the transaction lasts. |
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Once the transaction completes (commit or rollback) the lock is |
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released. |
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@param dc The transaction to attach the lock to |
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@param lock The lock to aquire |
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@return TRUE if the lock could be aquired (within 5 seconds), FALSE if not |
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*/ |
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public static boolean acquireLockForTransaction(DbControl dc, ReentrantLock lock) |
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{ |
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try |
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{ |
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lock.tryLock(5, TimeUnit.SECONDS); |
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} |
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catch (InterruptedException ex) |
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{} |
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boolean isLocked = lock.isHeldByCurrentThread(); |
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if (isLocked) |
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{ |
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dc.addTransactionalAction(new LockUtil(lock)); |
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} |
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return isLocked; |
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} |
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private final ReentrantLock lock; |
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private LockUtil(ReentrantLock lock) |
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{ |
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this.lock = lock; |
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} |
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@Override |
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public void onRollback() |
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{ |
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if (lock.isHeldByCurrentThread()) |
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{ |
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lock.unlock(); |
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} |
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} |
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@Override |
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public void onBeforeCommit() |
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{} |
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@Override |
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public void onAfterCommit() |
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{ |
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if (lock.isHeldByCurrentThread()) |
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{ |
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lock.unlock(); |
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} |
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} |
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} |