org.multiverse.api

Enum LockMode

java.lang.Object

java.lang.Enum<LockMode>

org.multiverse.api.LockMode

All Implemented Interfaces:

Serializable, Comparable<LockMode>, MultiverseConstants

public enum LockMode
extends Enum<LockMode>
implements MultiverseConstants

Using the LockMode one can control the pessimistic nature of a 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 Lock.

Author:

Peter Veentjer.

See Also:

TxnFactoryBuilder.setReadLockMode(LockMode), TxnFactoryBuilder.setWriteLockMode(LockMode), TxnConfig.getReadLockMode(), TxnConfig.getWriteLockMode(), TxnObject.getLock(), Lock

Enum Constant Summary

Enum Constants

Enum Constant and Description
Exclusive The ExclusiveLock can be compared with the writelock of a traditional read/write lock.
None No locking is done.
Read The LockMode.Read prevents others to acquire the Write/Exclusive-lock, but it allows others to acquire the Read lock.
Write The LockMode.Write prevents others to acquire the Read/Write/Exclusive-lock.

Field Summary

Fields inherited from interface org.multiverse.MultiverseConstants

LOCKMODE_EXCLUSIVE, LOCKMODE_NONE, LOCKMODE_READ, LOCKMODE_WRITE, SHAKE_BUGS, SPIN_YIELD, TRACING_ENABLED

Method Summary

Modifier and Type	Method and Description
int	asInt()
static LockMode	valueOf(String name) Returns the enum constant of this type with the specified name.
static LockMode[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

None

public static final LockMode None

No locking is done.

Read

public static final LockMode Read

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.

Write

public static final LockMode Write

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).

Exclusive

public static final LockMode Exclusive

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.

Method Detail

values

public static LockMode[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (LockMode c : LockMode.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static LockMode valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

asInt

public int asInt()