org.multiverse.api.LockMode Maven / Gradle / Ivy
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package org.multiverse.api;
import org.multiverse.MultiverseConstants;
/**
* Using the LockMode one can control the pessimistic nature of a {@link Txn}.
*
* Normally transactions are very optimistic (e.g. fail during execution or at the end because some read or
* write conflict was detected), but in some cases a more pessimistic approach is better. For more information
* see {@link Lock}.
*
* @author Peter Veentjer.
* @see TxnFactoryBuilder#setReadLockMode(LockMode)
* @see TxnFactoryBuilder#setWriteLockMode(LockMode)
* @see TxnConfig#getReadLockMode()
* @see TxnConfig#getWriteLockMode()
* @see TxnObject#getLock()
* @see Lock
*/
public enum LockMode implements MultiverseConstants {
/**
* No locking is done.
*/
None(LOCKMODE_NONE),
/**
* The LockMode.Read prevents others to acquire the Write/Exclusive-lock, but it allows others to acquire the
* Read lock. Unlike a traditional read/write-lock, it doesn't have to mean that other transactions can't write,
* it only prevents others from committing.
*/
Read(LOCKMODE_READ),
/**
* The LockMode.Write prevents others to acquire the Read/Write/Exclusive-lock. Unlike a traditional read-write lock,
* it doesn't have to mean that other transactions can't read or write, they only can't commit since the Exclusive lock
* is acquired for that (managed by the STM).
*/
Write(LOCKMODE_WRITE),
/**
* The ExclusiveLock can be compared with the writelock of a traditional read/write lock. once the Exclusive lock is acquired
* no other transaction can acquire any lock or can do any reading/writing (unless the transaction previously has read the
* transactional object).
*
*
The ExclusiveLock is the Lock acquired by the STM once a Txn is prepared for writing changes to a TxnObject.
*/
Exclusive(LOCKMODE_EXCLUSIVE);
private int lockModeAsInt;
private LockMode(int lockModeAsInt) {
this.lockModeAsInt = lockModeAsInt;
}
public int asInt() {
return lockModeAsInt;
}
}