org.rrd4j.core

Class RrdNioBackendFactory

java.lang.Object

org.rrd4j.core.RrdBackendFactory

org.rrd4j.core.RrdFileBackendFactory

org.rrd4j.core.RrdNioBackendFactory

All Implemented Interfaces:

Closeable, AutoCloseable

@RrdBackendAnnotation(name="NIO",
                      shouldValidateHeader=true)
public class RrdNioBackendFactory
extends RrdFileBackendFactory

Factory class which creates actual RrdNioBackend objects. This is the default factory since 1.4.0 version.

Managing the thread pool

Each RrdNioBackendFactory is optionally backed by a RrdSyncThreadPool, which it uses to sync the memory-mapped files to disk. In order to avoid having these threads live longer than they should, it is recommended that clients create and destroy thread pools at the appropriate time in their application's life time. Failure to manage thread pools appropriately may lead to the thread pool hanging around longer than necessary, which in turn may cause memory leaks.

if sync period is negative, no sync thread will be launched

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_SYNC_CORE_POOL_SIZE The core pool size for the sync executor.
static int	DEFAULT_SYNC_PERIOD Period in seconds between consecutive synchronizations when sync-mode is set to SYNC_BACKGROUND.

Fields inherited from class org.rrd4j.core.RrdBackendFactory

cachingAllowed, DEFAULTFACTORY, name, scheme, validateHeader

Constructor Summary

Constructors

Constructor and Description
RrdNioBackendFactory() Creates a new RrdNioBackendFactory with default settings.
RrdNioBackendFactory(int syncPeriod) Creates a new RrdNioBackendFactory, using a default RrdSyncThreadPool.
RrdNioBackendFactory(int syncPeriod, int syncPoolSize) Creates a new RrdNioBackendFactory.
RrdNioBackendFactory(int syncPeriod, RrdSyncThreadPool syncThreadPool) Creates a new RrdNioBackendFactory.
RrdNioBackendFactory(int syncPeriod, ScheduledExecutorService syncThreadPool) Creates a new RrdNioBackendFactory.

Method Summary

Modifier and Type	Method and Description
void	close() A generic close handle, default implementation does nothing.
static int	getSyncPeriod() Returns time between two consecutive background synchronizations.
static int	getSyncPoolSize() Returns the number of synchronizing threads.
RrdSyncThreadPool	getSyncThreadPool()
protected RrdBackend	open(String path, boolean readOnly)
static void	setSyncPeriod(int syncPeriod) Sets time between consecutive background synchronizations.
static void	setSyncPoolSize(int syncPoolSize) Sets the number of synchronizing threads.

Methods inherited from class org.rrd4j.core.RrdFileBackendFactory

canStore, exists, getCanonicalUri, getPath, getUri

Methods inherited from class org.rrd4j.core.RrdBackendFactory

addActiveFactories, buildGenericUri, checkClosing, exists, findFactory, getActiveFactories, getBackend, getBackend, getDefaultFactory, getName, getRootUri, getScheme, resolve, setActiveFactories, shouldValidateHeader, shouldValidateHeader

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_SYNC_CORE_POOL_SIZE

public static final int DEFAULT_SYNC_CORE_POOL_SIZE

The core pool size for the sync executor. Defaults to 6.

See Also:

Constant Field Values

DEFAULT_SYNC_PERIOD

public static final int DEFAULT_SYNC_PERIOD

Period in seconds between consecutive synchronizations when sync-mode is set to SYNC_BACKGROUND. By default in-memory cache will be transferred to the disc every 300 seconds (5 minutes). Default value can be changed via setSyncPeriod(int) method.

See Also:

Constant Field Values

Constructor Detail

RrdNioBackendFactory

public RrdNioBackendFactory()

Creates a new RrdNioBackendFactory with default settings.

RrdNioBackendFactory

public RrdNioBackendFactory(int syncPeriod)

Creates a new RrdNioBackendFactory, using a default RrdSyncThreadPool.

Parameters:

syncPeriod - the sync period, in seconds. If negative or 0, sync threads are disabled.

RrdNioBackendFactory

public RrdNioBackendFactory(int syncPeriod,
                            int syncPoolSize)

Creates a new RrdNioBackendFactory.

Parameters:

syncPeriod - the sync period, in seconds.

syncPoolSize - The number of threads to use to sync the mapped file to disk, if negative or 0, sync threads are disabled.

RrdNioBackendFactory

public RrdNioBackendFactory(int syncPeriod,
                            RrdSyncThreadPool syncThreadPool)

Creates a new RrdNioBackendFactory.

Parameters:

syncPeriod - the sync period, in seconds.

syncThreadPool - If null, disable background sync threads

RrdNioBackendFactory

public RrdNioBackendFactory(int syncPeriod,
                            ScheduledExecutorService syncThreadPool)

Creates a new RrdNioBackendFactory.

Parameters:

syncPeriod - the sync period, in seconds.

syncThreadPool - If null, disable background sync threads

Method Detail

close

public void close()

Description copied from class: RrdBackendFactory

A generic close handle, default implementation does nothing.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class RrdBackendFactory

getSyncPeriod

public static int getSyncPeriod()

Returns time between two consecutive background synchronizations. If not changed via setSyncPeriod(int) method call, defaults to DEFAULT_SYNC_PERIOD. See setSyncPeriod(int) for more information.

Returns:

Time in seconds between consecutive background synchronizations.

getSyncPoolSize

public static int getSyncPoolSize()

Returns the number of synchronizing threads. If not changed via setSyncPoolSize(int) method call, defaults to DEFAULT_SYNC_CORE_POOL_SIZE. See setSyncPoolSize(int) for more information.

Returns:

Number of synchronizing threads.

getSyncThreadPool

public RrdSyncThreadPool getSyncThreadPool()

Returns:

The RrdSyncThreadPool or null if syncing is disabled

open

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

Creates RrdNioBackend object for the given file path.

Specified by:

open in class RrdBackendFactory

Throws:

IOException

setSyncPeriod

public static void setSyncPeriod(int syncPeriod)

Sets time between consecutive background synchronizations. If negative, it will disabling syncing for all NIO backend factory.

Parameters:

syncPeriod - Time in seconds between consecutive background synchronizations.

setSyncPoolSize

public static void setSyncPoolSize(int syncPoolSize)

Sets the number of synchronizing threads. It must be set before the first use of this factory. It will not have any effect afterward.

Parameters:

syncPoolSize - Number of synchronizing threads.