org.tmatesoft.sqljet.core.internal.fs
Class SqlJetFile

java.lang.Object
  extended by org.tmatesoft.sqljet.core.internal.fs.SqlJetFile
All Implemented Interfaces:
ISqlJetFile

public class SqlJetFile
extends java.lang.Object
implements ISqlJetFile


Field Summary
static int SQLJET_DEFAULT_SECTOR_SIZE
           
 
Fields inherited from interface org.tmatesoft.sqljet.core.internal.ISqlJetFile
PENDING_BYTE, RESERVED_BYTE, SHARED_FIRST, SHARED_SIZE
 
Method Summary
 boolean checkReservedLock()
          This routine checks if there is a RESERVED lock held on the specified file by this or any other process.
 void close()
          Close a file.
 java.util.Set<SqlJetDeviceCharacteristics> deviceCharacteristics()
          Return the device characteristics for the file.
 long fileSize()
          Determine the current size of a file in bytes
 SqlJetFileType getFileType()
          Returns file type.
 SqlJetLockType getLockType()
          Returns lock type of file.
 java.util.Set<SqlJetFileOpenPermission> getPermissions()
          Returns assiciated permissions.
 boolean isMemJournal()
          Return true if the file-handle passed as an argument is an in-memory journal
 boolean lock(SqlJetLockType lockType)
          Lock the file with the lock specified by parameter locktype - one of the following: (1) SHARED (2) RESERVED (3) PENDING (4) EXCLUSIVE Sometimes when requesting one lock state, additional lock states are inserted in between.
 int read(ISqlJetMemoryPointer buffer, int amount, long offset)
          Read data from a file into a buffer.
 int sectorSize()
          Return the sector size in bytes of the underlying block device for the specified file.
 void sync(java.util.Set<SqlJetSyncFlags> syncFlags)
          Make sure all writes to a particular file are committed to disk.
 void truncate(long size)
          Truncate an open file to a specified size
 boolean unlock(SqlJetLockType lockType)
          Lower the locking level on file descriptor pFile to locktype.
 void write(ISqlJetMemoryPointer buffer, int amount, long offset)
          Write data from a buffer into a file.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SQLJET_DEFAULT_SECTOR_SIZE

public static final int SQLJET_DEFAULT_SECTOR_SIZE
See Also:
Constant Field Values
Method Detail

getFileType

public SqlJetFileType getFileType()
Description copied from interface: ISqlJetFile
Returns file type.

Specified by:
getFileType in interface ISqlJetFile
Returns:
SqlJetFileType

getPermissions

public java.util.Set<SqlJetFileOpenPermission> getPermissions()
Description copied from interface: ISqlJetFile
Returns assiciated permissions.

Specified by:
getPermissions in interface ISqlJetFile
Returns:
SqlJetFileOpenPermission

close

public void close()
           throws SqlJetException
Description copied from interface: ISqlJetFile
Close a file.

Specified by:
close in interface ISqlJetFile
Throws:
SqlJetException

read

public int read(ISqlJetMemoryPointer buffer,
                int amount,
                long offset)
         throws SqlJetIOException
Description copied from interface: ISqlJetFile
Read data from a file into a buffer.

Specified by:
read in interface ISqlJetFile
Returns:
Throws:
SqlJetIOException

write

public void write(ISqlJetMemoryPointer buffer,
                  int amount,
                  long offset)
           throws SqlJetIOException
Description copied from interface: ISqlJetFile
Write data from a buffer into a file.

Specified by:
write in interface ISqlJetFile
Throws:
SqlJetIOException

truncate

public void truncate(long size)
              throws SqlJetIOException
Description copied from interface: ISqlJetFile
Truncate an open file to a specified size

Specified by:
truncate in interface ISqlJetFile
Throws:
SqlJetIOException

sync

public void sync(java.util.Set<SqlJetSyncFlags> syncFlags)
          throws SqlJetIOException
Description copied from interface: ISqlJetFile
Make sure all writes to a particular file are committed to disk. If dataOnly==false then both the file itself and its metadata (file size, access time, etc) are synced. If dataOnly==true then only the file data is synced. Also make sure that the directory entry for the file has been created by fsync-ing the directory that contains the file. If we do not do this and we encounter a power failure, the directory entry for the journal might not exist after we reboot. The next SqlJet to access the file will not know that the journal exists (because the directory entry for the journal was never created) and the transaction will not roll back - possibly leading to database corruption.

Specified by:
sync in interface ISqlJetFile
Throws:
SqlJetIOException

fileSize

public long fileSize()
              throws SqlJetException
Description copied from interface: ISqlJetFile
Determine the current size of a file in bytes

Specified by:
fileSize in interface ISqlJetFile
Returns:
Throws:
SqlJetException

getLockType

public SqlJetLockType getLockType()
Description copied from interface: ISqlJetFile
Returns lock type of file.

Specified by:
getLockType in interface ISqlJetFile
Returns:

lock

public boolean lock(SqlJetLockType lockType)
             throws SqlJetIOException
Description copied from interface: ISqlJetFile
Lock the file with the lock specified by parameter locktype - one of the following: (1) SHARED (2) RESERVED (3) PENDING (4) EXCLUSIVE Sometimes when requesting one lock state, additional lock states are inserted in between. The locking might fail on one of the later transitions leaving the lock state different from what it started but still short of its goal. The following chart shows the allowed transitions and the inserted intermediate states: UNLOCKED -> SHARED SHARED -> RESERVED SHARED -> (PENDING) -> EXCLUSIVE RESERVED -> (PENDING) -> EXCLUSIVE PENDING -> EXCLUSIVE This routine will only increase a lock.

Specified by:
lock in interface ISqlJetFile
Returns:
Throws:
SqlJetIOException

unlock

public boolean unlock(SqlJetLockType lockType)
               throws SqlJetIOException
Description copied from interface: ISqlJetFile
Lower the locking level on file descriptor pFile to locktype. locktype must be either NONE or SHARED. If the locking level of the file descriptor is already at or below the requested locking level, this routine is a no-op.

Specified by:
unlock in interface ISqlJetFile
Returns:
Throws:
SqlJetIOException

checkReservedLock

public boolean checkReservedLock()
Description copied from interface: ISqlJetFile
This routine checks if there is a RESERVED lock held on the specified file by this or any other process. The return value is set unless an I/O error occurs during lock checking.

Specified by:
checkReservedLock in interface ISqlJetFile
Returns:

sectorSize

public int sectorSize()
Description copied from interface: ISqlJetFile
Return the sector size in bytes of the underlying block device for the specified file. This is almost always 512 bytes, but may be larger for some devices. SqlJet code assumes this function cannot fail. It also assumes that if two files are created in the same file-system directory (i.e. a database and its journal file) that the sector size will be the same for both.

Specified by:
sectorSize in interface ISqlJetFile
Returns:

deviceCharacteristics

public java.util.Set<SqlJetDeviceCharacteristics> deviceCharacteristics()
Description copied from interface: ISqlJetFile
Return the device characteristics for the file.

Specified by:
deviceCharacteristics in interface ISqlJetFile
Returns:

isMemJournal

public boolean isMemJournal()
Description copied from interface: ISqlJetFile
Return true if the file-handle passed as an argument is an in-memory journal

Specified by:
isMemJournal in interface ISqlJetFile