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	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	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, ScheduledExecutorService syncThreadPool)`	Creates a new RrdNioBackendFactory.
`RrdNioBackendFactory(int syncPeriod, RrdSyncThreadPool syncThreadPool)`	Creates a new RrdNioBackendFactory.

Method Summary

Modifier and Type	Method	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)`	Creates RrdNioBackend object for the given file path.
`static void`	`setSyncPeriod(int syncPeriod)`	Sets time between consecutive background synchronizations.
`static void`	`setSyncPoolSize(int syncPoolSize)`	Sets the number of synchronizing threads.
`void`	`setSyncThreadPool(ScheduledExecutorService syncThreadPool)`	Deprecated. Create a custom instance instead
`void`	`setSyncThreadPool(RrdSyncThreadPool syncThreadPool)`	Deprecated. Create a custom instance instead

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, 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 Details
- 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
- 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
Constructor Details
- 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, ScheduledExecutorService syncThreadPool)
  
  Creates a new RrdNioBackendFactory.
  
  Parameters:
  
  syncPeriod - the sync period, in seconds.
  
  syncThreadPool - If null, disable background sync threads
- 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
Method Details
- 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.
- 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.
- 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.
- 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.
- setSyncThreadPool
  
  @Deprecated public void setSyncThreadPool(RrdSyncThreadPool syncThreadPool)
  
  Deprecated.
  Create a custom instance instead
  
  Setter for the field syncThreadPool.
  
  Parameters:
  
  syncThreadPool - the RrdSyncThreadPool to use to sync the memory-mapped files.
- setSyncThreadPool
  
  @Deprecated public void setSyncThreadPool(ScheduledExecutorService syncThreadPool)
  
  Deprecated.
  Create a custom instance instead
  
  Setter for the field syncThreadPool.
  
  Parameters:
  
  syncThreadPool - the ScheduledExecutorService that will back the RrdSyncThreadPool used to sync the memory-mapped files.
- 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
- getSyncThreadPool
  
  public RrdSyncThreadPool getSyncThreadPool()
  
  Returns:
  
  The RrdSyncThreadPool or null if syncing is disabled
- close
  
  public void close() throws IOException
  
  Description copied from class: RrdBackendFactory
  
  A generic close handle, default implementation does nothing.
  
  Specified by:
  
  close in interface AutoCloseable
  
  Specified by:
  
  close in interface Closeable
  
  Overrides:
  
  close in class RrdBackendFactory
  
  Throws:
  
  IOException - if the close fails

Class RrdNioBackendFactory