Package org.h2.store

Interface DataHandler

  • All Known Implementing Classes:
    Database, Recover, SessionRemote

    public interface DataHandler
    A data handler contains a number of callback methods, mostly related to CLOB and BLOB handling. The most important implementing class is a database.
    • Method Detail

      • getDatabasePath

        java.lang.String getDatabasePath()
        Get the database path.
        Returns:
        the database path
      • openFile

        FileStore openFile​(java.lang.String name,
                           java.lang.String mode,
                           boolean mustExist)
        Open a file at the given location.
        Parameters:
        name - the file name
        mode - the mode
        mustExist - whether the file must already exist
        Returns:
        the file
      • checkPowerOff

        void checkPowerOff()
                    throws DbException
        Check if the simulated power failure occurred. This call will decrement the countdown.
        Throws:
        DbException - if the simulated power failure occurred
      • checkWritingAllowed

        void checkWritingAllowed()
                          throws DbException
        Check if writing is allowed.
        Throws:
        DbException - if it is not allowed
      • getMaxLengthInplaceLob

        int getMaxLengthInplaceLob()
        Get the maximum length of a in-place large object
        Returns:
        the maximum size
      • getTempFileDeleter

        TempFileDeleter getTempFileDeleter()
        Get the temp file deleter mechanism.
        Returns:
        the temp file deleter
      • getLobSyncObject

        java.lang.Object getLobSyncObject()
        Get the synchronization object for lob operations.
        Returns:
        the synchronization object
      • getLobFileListCache

        SmallLRUCache<java.lang.String,​java.lang.String[]> getLobFileListCache()
        Get the lob file list cache if it is used.
        Returns:
        the cache or null
      • getLobStorage

        LobStorageInterface getLobStorage()
        Get the lob storage mechanism to use.
        Returns:
        the lob storage mechanism
      • readLob

        int readLob​(long lobId,
                    byte[] hmac,
                    long offset,
                    byte[] buff,
                    int off,
                    int length)
        Read from a lob.
        Parameters:
        lobId - the lob id
        hmac - the message authentication code
        offset - the offset within the lob
        buff - the target buffer
        off - the offset within the target buffer
        length - the number of bytes to read
        Returns:
        the number of bytes read
      • getCompareMode

        CompareMode getCompareMode()
        Return compare mode.
        Returns:
        Compare mode.