Package com.helger.commons.id.factory

Class FileLongIDFactory

java.lang.Object
com.helger.commons.id.factory.AbstractPersistingLongIDFactory
com.helger.commons.id.factory.FileLongIDFactory
All Implemented Interfaces:
IBaseIDFactory, ILongIDFactory
@ThreadSafe public class FileLongIDFactory extends AbstractPersistingLongIDFactory
File based persisting ILongIDFactory implementation.
Author:
Philip Helger

  • Field Details

    • CHARSET_TO_USE

      public static final Charset CHARSET_TO_USE
      The charset to use for writing the file

    • DEFAULT_RESERVE_COUNT

      public static final int DEFAULT_RESERVE_COUNT
      The default number of values to reserve with a single IO action
      See Also:

  • Constructor Details

  • Method Details

    • getFile

      @Nonnull public final File getFile()
      Returns:
      The File to write to, as provided in the constructor. Never null.

    • readAndUpdateIDCounter

      protected final long readAndUpdateIDCounter(@Nonnegative int nReserveCount)
      Description copied from class: AbstractPersistingLongIDFactory
      Read the current ID from the device. In case the method is called for a non-initialized device, 0 should be returned.
      The update should write the read value plus the passed reserve count back to the device. This method should perform an atomic read and update to avoid that ID can be reused.
      Pseudo code: 
       protected long readAndUpdateIDCounter (int nReserveCount)
 {
   final long nRead = FileIO.read (file);
   FileIO.write (file, nRead + nReserveCount);
   return nRead;
 }
      Specified by:
      readAndUpdateIDCounter in class AbstractPersistingLongIDFactory
      Parameters:
      nReserveCount - the number that should be added to the read value. Always > 0.
      Returns:
      0 if this method is called for a non-initialized device, the value read from the device otherwise or CGlobal.ILLEGAL_ULONG in case of an error.

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class AbstractPersistingLongIDFactory

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class AbstractPersistingLongIDFactory

    • toString

      public String toString()
      Overrides:
      toString in class AbstractPersistingLongIDFactory