com.tangosol.io.bdb

Class DatabaseFactory.EnvironmentHolder.DirectoryLock

java.lang.Object

com.tangosol.io.bdb.DatabaseFactory.EnvironmentHolder.DirectoryLock

Enclosing class:

DatabaseFactory.EnvironmentHolder

protected static class DatabaseFactory.EnvironmentHolder.DirectoryLock
extends Object

Directory based lock.

A single instance of the DirectoryLock is not intended for inter thread locking. Multiple instance referring to the same File should be used instead.

Field Summary

Fields

Modifier and Type	Field	Description
static String	LOCK_FILE_NAME	Name of warning file.
protected File	m_dir	Directory to lock.
protected FileOutputStream	m_fstreamLocked	The FileStream which the actual lock is held on.
protected FileLock	m_lockDir	The actual FileLock.
protected String	m_sLockText	Text to include in the lock file.

Constructor Summary

Constructors

Constructor	Description
DirectoryLock(File dir, String sLockText)	Create a DirectoryLock which can be used to try to lock a directory.

Method Summary

Modifier and Type	Method	Description
protected void	finalize()	Automatically release the lock on finalization.
boolean	tryLock()	Try to lock the directory.
boolean	tryUnlock()	Try to unlock the directory.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOCK_FILE_NAME

public static final String LOCK_FILE_NAME

Name of warning file.

See Also:

Constant Field Values

m_dir

protected File m_dir

Directory to lock.

m_fstreamLocked

protected FileOutputStream m_fstreamLocked

The FileStream which the actual lock is held on.

m_lockDir

protected FileLock m_lockDir

The actual FileLock.

m_sLockText

protected String m_sLockText

Text to include in the lock file.

Constructor Detail

DirectoryLock

public DirectoryLock(File dir,
                     String sLockText)

Create a DirectoryLock which can be used to try to lock a directory. The object is created in an unlocked state.

Parameters:

dir - the directory to lock

sLockText - the text to include in the lock file

Method Detail

tryLock

public boolean tryLock()
                throws IOException

Try to lock the directory.

Returns:

true if a lock is obtained, false if it is locked by another DirectoryLock

Throws:

IOException - if an IO error occurs while creating the lock file

tryUnlock

public boolean tryUnlock()
                  throws IOException

Try to unlock the directory.

Returns:

true if a lock is released, false if the directory was not locked by this DirectoryLock

Throws:

IOException - if an IO error occurs while deleting the lock file, the lock may be left in an unlocked state

finalize

protected void finalize()
                 throws Throwable

Automatically release the lock on finalization.

The OS will ensure that the lock is released regardless but this allows the lock file to be deleted as well.

Overrides:

finalize in class Object

Throws:

Throwable - if an error occurs