tp
Interface LM

All Known Implementing Classes:

MyLM

public interface LM

Lock Manager interface

Nested Class Summary

static class	LM.DeadLockException
static class	LM.LockType

Field Summary

static long

DEFAULT_DEADLOCK_TIMEOUT A transaction is considered in deadlock if it waits for lock more than 10 seconds.

Method Summary

void	lockForRead(Transaction context, Lockable resource) obtain a read lock for given resource
void	lockForWrite(Transaction context, Lockable resource) obtain a write lock for given resource
void	setDeadlockTimeout(long ms) Set deadlock timeout in millisecond.
void	unlockAll(Transaction context) unlock all locks held by the transaction

Field Detail

DEFAULT_DEADLOCK_TIMEOUT

static final long DEFAULT_DEADLOCK_TIMEOUT

A transaction is considered in deadlock if it waits for lock more than 10 seconds.

See Also:

setDeadlockTimeout(long), Constant Field Values

Method Detail

lockForRead

void lockForRead(Transaction context,
                 Lockable resource)
                 throws LM.DeadLockException,
                        InterruptedException

obtain a read lock for given resource

Parameters:

context - transaction identifier

resource - lockable resource identifier

Throws:

LM.DeadLockException - deadlock detected by either timeout or explicit deadlock detection algorithm

InterruptedException - thread has been interrupted by coordination thread

lockForWrite

void lockForWrite(Transaction context,
                  Lockable resource)
                  throws LM.DeadLockException,
                         InterruptedException

obtain a write lock for given resource

Parameters:

context - transaction identifier

resource - lockable resource identifier

Throws:

LM.DeadLockException - deadlock detected by either timeout or explicit deadlock detection algorithm

InterruptedException - thread has been interrupted by coordination thread

unlockAll

void unlockAll(Transaction context)

unlock all locks held by the transaction

Parameters:

context - transaction identifier

setDeadlockTimeout

void setDeadlockTimeout(long ms)

Set deadlock timeout in millisecond. The default value is 10 seconds. Use this interface for testing concurrency control.

Parameters:

ms - timeout value in millisecond