Package org.h2.store.fs.niomem

Class FileNioMemData

java.lang.Object
org.h2.store.fs.niomem.FileNioMemData
class FileNioMemData extends Object
This class contains the data of an in-memory random access file. Data compression using the LZF algorithm is supported as well.

  • Field Details

    • CACHE_MIN_SIZE

      private static final int CACHE_MIN_SIZE
      See Also:

    • BLOCK_SIZE_SHIFT

      private static final int BLOCK_SIZE_SHIFT
      See Also:

    • BLOCK_SIZE

      private static final int BLOCK_SIZE
      See Also:

    • BLOCK_SIZE_MASK

      private static final int BLOCK_SIZE_MASK
      See Also:

    • COMPRESSED_EMPTY_BLOCK

      private static final ByteBuffer COMPRESSED_EMPTY_BLOCK

    • LZF_THREAD_LOCAL

      private static final ThreadLocal<CompressLZF> LZF_THREAD_LOCAL

    • COMPRESS_OUT_BUF_THREAD_LOCAL

      private static final ThreadLocal<byte[]> COMPRESS_OUT_BUF_THREAD_LOCAL
      the output buffer when compressing

    • nameHashCode

      final int nameHashCode
      The hash code of the name.

    • compressLaterCache

      private final FileNioMemData.CompressLaterCache<FileNioMemData.CompressItem,FileNioMemData.CompressItem> compressLaterCache

    • name

      private String name

    • compress

      private final boolean compress

    • compressLaterCachePercent

      private final float compressLaterCachePercent

    • length

      private volatile long length

    • buffers

      private AtomicReference<ByteBuffer>[] buffers

    • lastModified

      private long lastModified

    • isReadOnly

      private boolean isReadOnly

    • isLockedExclusive

      private boolean isLockedExclusive

    • sharedLockCount

      private int sharedLockCount

    • rwLock

      private final ReentrantReadWriteLock rwLock

  • Constructor Details

    • FileNioMemData

      FileNioMemData(String name, boolean compress, float compressLaterCachePercent)

  • Method Details

    • lockExclusive

      boolean lockExclusive()
      Lock the file in exclusive mode if possible.
      Returns:
      if locking was successful

    • lockShared

      boolean lockShared()
      Lock the file in shared mode if possible.
      Returns:
      if locking was successful

    • unlock

      void unlock()
      Unlock the file.

    • addToCompressLaterCache

      private void addToCompressLaterCache(int page)

    • expandPage

      private ByteBuffer expandPage(int page)

    • compressPage

      void compressPage(int page)
      Compress the data in a byte array.
      Parameters:
      page - which page to compress

    • touch

      void touch(boolean openReadOnly)
      Update the last modified time.
      Parameters:
      openReadOnly - if the file was opened in read-only mode

    • length

      long length()
      Get the file length.
      Returns:
      the length

    • truncate

      void truncate(long newLength)
      Truncate the file.
      Parameters:
      newLength - the new length

    • changeLength

      private void changeLength(long len)

    • readWrite

      long readWrite(long pos, ByteBuffer b, int off, int len, boolean write)
      Read or write.
      Parameters:
      pos - the position
      b - the byte array
      off - the offset within the byte array
      len - the number of bytes
      write - true for writing
      Returns:
      the new position

    • setName

      void setName(String name)
      Set the file name.
      Parameters:
      name - the name

    • getName

      String getName()
      Get the file name
      Returns:
      the name

    • getLastModified

      long getLastModified()
      Get the last modified time.
      Returns:
      the time

    • canWrite

      boolean canWrite()
      Check whether writing is allowed.
      Returns:
      true if it is

    • setReadOnly

      boolean setReadOnly()
      Set the read-only flag.
      Returns:
      true