Package 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 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:

    • 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:

  • 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