Package org.rrd4j.core

Class RrdSafeFileBackendFactory

java.lang.Object

org.rrd4j.core.RrdBackendFactory

org.rrd4j.core.RrdFileBackendFactory

org.rrd4j.core.RrdRandomAccessFileBackendFactory

org.rrd4j.core.RrdSafeFileBackendFactory

All Implemented Interfaces:

Closeable, AutoCloseable

@RrdBackendAnnotation(name="SAFE",
                      shouldValidateHeader=true,
                      cachingAllowed=false)
public class RrdSafeFileBackendFactory
extends RrdRandomAccessFileBackendFactory

Factory class which creates actual RrdSafeFileBackend objects.

Because of locking, each RrdDb can be open only once even from within the JVM. So usage of the RrdDbPool is mandatory with this backend.

Field Summary

Fields

Modifier and Type	Field	Description
static long	LOCK_RETRY_PERIOD	Default time between two consecutive file locking attempts.
static long	LOCK_WAIT_TIME	Default time (in milliseconds) this backend will wait for a file lock.

Fields inherited from class org.rrd4j.core.RrdBackendFactory

cachingAllowed, DEFAULTFACTORY, name, scheme, validateHeader

Constructor Summary

Constructors

Constructor	Description
RrdSafeFileBackendFactory()	Generate a factory using the default system wide lock settings
RrdSafeFileBackendFactory(long lockWaitTime, long lockRetryPeriod)	Generate a factory with custom lock settings

Method Summary

Modifier and Type	Method	Description
static long	getLockRetryPeriod()	Returns time between two consecutive file locking attempts.
static long	getLockWaitTime()	Returns time this backend will wait for a file lock.
protected RrdBackend	open(String path, boolean readOnly)	Creates RrdFileBackend object for the given file path.
static void	setLockRetryPeriod(long lockRetryPeriod)	Sets time between two consecutive file locking attempts.
static void	setLockWaitTime(long lockWaitTime)	Sets time this backend will wait for a file lock.

Methods inherited from class org.rrd4j.core.RrdFileBackendFactory

canStore, exists, getCanonicalUri, getPath, getUri

Methods inherited from class org.rrd4j.core.RrdBackendFactory

addActiveFactories, addFactories, buildGenericUri, checkClosing, close, exists, findFactory, getActiveFactories, getBackend, getBackend, getDefaultFactory, getFactory, getName, getRootUri, getScheme, registerAndSetAsDefaultFactory, registerFactory, resolve, setActiveFactories, setDefaultFactory, shouldValidateHeader, shouldValidateHeader

Methods inherited from class java.lang.Object

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

Field Detail

LOCK_WAIT_TIME

public static final long LOCK_WAIT_TIME

Default time (in milliseconds) this backend will wait for a file lock.

See Also:

Constant Field Values

LOCK_RETRY_PERIOD

public static final long LOCK_RETRY_PERIOD

Default time between two consecutive file locking attempts.

See Also:

Constant Field Values

Constructor Detail

RrdSafeFileBackendFactory

public RrdSafeFileBackendFactory()

Generate a factory using the default system wide lock settings

RrdSafeFileBackendFactory

public RrdSafeFileBackendFactory(long lockWaitTime,
                                 long lockRetryPeriod)

Generate a factory with custom lock settings

Parameters:

lockWaitTime - wait time in ms

lockRetryPeriod - retry period in ms

Method Detail

open

protected RrdBackend open(String path,
                          boolean readOnly)
                   throws IOException

Creates RrdFileBackend object for the given file path. Creates RrdSafeFileBackend object for the given file path.

Overrides:

open in class RrdRandomAccessFileBackendFactory

Throws:

IOException

getLockWaitTime

public static long getLockWaitTime()

Returns time this backend will wait for a file lock.

Returns:

Time (in milliseconds) this backend will wait for a file lock.

setLockWaitTime

public static void setLockWaitTime(long lockWaitTime)

Sets time this backend will wait for a file lock.

Parameters:

lockWaitTime - Maximum lock wait time (in milliseconds)

getLockRetryPeriod

public static long getLockRetryPeriod()

Returns time between two consecutive file locking attempts.

Returns:

Time (im milliseconds) between two consecutive file locking attempts.

setLockRetryPeriod

public static void setLockRetryPeriod(long lockRetryPeriod)

Sets time between two consecutive file locking attempts.

Parameters:

lockRetryPeriod - time (in milliseconds) between two consecutive file locking attempts.