FileStore

java.lang.Object
- org.h2.mvstore.FileStore

Direct Known Subclasses:

OffHeapStore
```
public class FileStore
extends java.lang.Object
```
The default storage mechanism of the MVStore. This implementation persists data to a file. The file store is responsible to persist data and for free space management.

Field Summary

Fields
Modifier and Type	Field and Description
`protected java.nio.channels.FileChannel`	`encryptedFile` The encrypted file (if encryption is used).
`protected java.nio.channels.FileChannel`	`file` The file.
`protected java.nio.channels.FileLock`	`fileLock` The file lock.
`protected java.lang.String`	`fileName` The file name.
`protected long`	`fileSize` The file size (cached).
`protected FreeSpaceBitSet`	`freeSpace` The free spaces between the chunks.
`protected java.util.concurrent.atomic.AtomicLong`	`readBytes` The number of read bytes.
`protected java.util.concurrent.atomic.AtomicLong`	`readCount` The number of read operations.
`protected boolean`	`readOnly` Whether this store is read-only.
`protected java.util.concurrent.atomic.AtomicLong`	`writeBytes` The number of written bytes.
`protected java.util.concurrent.atomic.AtomicLong`	`writeCount` The number of write operations.

Constructor Summary

Constructors
Constructor and Description

FileStore()

Constructors
Constructor and Description
`FileStore()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`long`	`allocate(int length)` Allocate a number of blocks and mark them as used.
`void`	`clear()` Mark the file as empty.
`void`	`close()` Close this store.
`void`	`free(long pos, int length)` Mark the space as free.
`int`	`getDefaultRetentionTime()` Get the default retention time for this store in milliseconds.
`java.nio.channels.FileChannel`	`getEncryptedFile()` Get the encrypted file instance, if encryption is used.
`java.nio.channels.FileChannel`	`getFile()` Get the file instance in use.
`java.lang.String`	`getFileName()` Get the file name.
`int`	`getFillRate()`
`long`	`getReadBytes()` Get the number of read bytes since this store was opened.
`long`	`getReadCount()` Get the number of read operations since this store was opened.
`long`	`getWriteBytes()` Get the number of written bytes since this store was opened.
`long`	`getWriteCount()` Get the number of write operations since this store was opened.
`boolean`	`isReadOnly()`
`void`	`markUsed(long pos, int length)` Mark the space as in use.
`void`	`open(java.lang.String fileName, boolean readOnly, char[] encryptionKey)` Try to open the file.
`java.nio.ByteBuffer`	`readFully(long pos, int len)` Read from the file.
`long`	`size()` Get the file size.
`void`	`sync()` Flush all changes.
`java.lang.String`	`toString()`
`void`	`truncate(long size)` Truncate the file.
`void`	`writeFully(long pos, java.nio.ByteBuffer src)` Write to the file.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - readCount
```
protected final java.util.concurrent.atomic.AtomicLong readCount
```
    The number of read operations.
  - readBytes
```
protected final java.util.concurrent.atomic.AtomicLong readBytes
```
    The number of read bytes.
  - writeCount
```
protected final java.util.concurrent.atomic.AtomicLong writeCount
```
    The number of write operations.
  - writeBytes
```
protected final java.util.concurrent.atomic.AtomicLong writeBytes
```
    The number of written bytes.
  - freeSpace
```
protected final FreeSpaceBitSet freeSpace
```
    The free spaces between the chunks. The first block to use is block 2 (the first two blocks are the store header).
  - fileName
```
protected java.lang.String fileName
```
    The file name.
  - readOnly
```
protected boolean readOnly
```
    Whether this store is read-only.
  - fileSize
```
protected long fileSize
```
    The file size (cached).
  - file
```
protected java.nio.channels.FileChannel file
```
    The file.
  - encryptedFile
```
protected java.nio.channels.FileChannel encryptedFile
```
    The encrypted file (if encryption is used).
  - fileLock
```
protected java.nio.channels.FileLock fileLock
```
    The file lock.
- Constructor Detail
  - FileStore
```
public FileStore()
```
- Method Detail
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - readFully
```
public java.nio.ByteBuffer readFully(long pos,
                                     int len)
```
    Read from the file.
    
    Parameters:
    
    pos - the write position
    
    len - the number of bytes to read
    
    Returns:
    
    the byte buffer
  - writeFully
```
public void writeFully(long pos,
                       java.nio.ByteBuffer src)
```
    Write to the file.
    
    Parameters:
    
    pos - the write position
    
    src - the source buffer
  - open
```
public void open(java.lang.String fileName,
                 boolean readOnly,
                 char[] encryptionKey)
```
    Try to open the file.
    
    Parameters:
    
    fileName - the file name
    
    readOnly - whether the file should only be opened in read-only mode, even if the file is writable
    
    encryptionKey - the encryption key, or null if encryption is not used
  - close
```
public void close()
```
    Close this store.
  - sync
```
public void sync()
```
    Flush all changes.
  - size
```
public long size()
```
    Get the file size.
    
    Returns:
    
    the file size
  - truncate
```
public void truncate(long size)
```
    Truncate the file.
    
    Parameters:
    
    size - the new file size
  - getFile
```
public java.nio.channels.FileChannel getFile()
```
    Get the file instance in use.
    The application may read from the file (for example for online backup), but not write to it or truncate it.
    
    Returns:
    
    the file
  - getEncryptedFile
```
public java.nio.channels.FileChannel getEncryptedFile()
```
    Get the encrypted file instance, if encryption is used.
    The application may read from the file (for example for online backup), but not write to it or truncate it.
    
    Returns:
    
    the encrypted file, or null if encryption is not used
  - getWriteCount
```
public long getWriteCount()
```
    Get the number of write operations since this store was opened. For file based stores, this is the number of file write operations.
    
    Returns:
    
    the number of write operations
  - getWriteBytes
```
public long getWriteBytes()
```
    Get the number of written bytes since this store was opened.
    
    Returns:
    
    the number of write operations
  - getReadCount
```
public long getReadCount()
```
    Get the number of read operations since this store was opened. For file based stores, this is the number of file read operations.
    
    Returns:
    
    the number of read operations
  - getReadBytes
```
public long getReadBytes()
```
    Get the number of read bytes since this store was opened.
    
    Returns:
    
    the number of write operations
  - isReadOnly
```
public boolean isReadOnly()
```
  - getDefaultRetentionTime
```
public int getDefaultRetentionTime()
```
    Get the default retention time for this store in milliseconds.
    
    Returns:
    
    the retention time
  - markUsed
```
public void markUsed(long pos,
                     int length)
```
    Mark the space as in use.
    
    Parameters:
    
    pos - the position in bytes
    
    length - the number of bytes
  - allocate
```
public long allocate(int length)
```
    Allocate a number of blocks and mark them as used.
    
    Parameters:
    
    length - the number of bytes to allocate
    
    Returns:
    
    the start position in bytes
  - free
```
public void free(long pos,
                 int length)
```
    Mark the space as free.
    
    Parameters:
    
    pos - the position in bytes
    
    length - the number of bytes
  - getFillRate
```
public int getFillRate()
```
  - clear
```
public void clear()
```
    Mark the file as empty.
  - getFileName
```
public java.lang.String getFileName()
```
    Get the file name.
    
    Returns:
    
    the file name

Class FileStore

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

readCount

readBytes

writeCount

writeBytes

freeSpace

fileName

readOnly

fileSize

file

encryptedFile

fileLock

Constructor Detail

FileStore

Method Detail

toString

readFully

writeFully

open

close

sync

size

truncate

getFile

getEncryptedFile

getWriteCount

getWriteBytes

getReadCount

getReadBytes

isReadOnly

getDefaultRetentionTime

markUsed

allocate

free

getFillRate

clear

getFileName