org.apache.derby.impl.jdbc

Class LOBFile

java.lang.Object

org.apache.derby.impl.jdbc.LOBFile

Direct Known Subclasses:

EncryptedLOBFile

 class LOBFile
extends java.lang.Object

LOBFile is a wrapper over StorageRandomAccessFile. The purpose of this class is to let the user of this class access StorageRandomAccessFile in plain and in encrypted for without having to change code.

Field Summary

Fields

Modifier and Type	Field and Description
private StorageRandomAccessFile	randomAccessFile An object giving random access to storageFile.
private StorageFile	storageFile The temporary file where the contents of the LOB should be stored.

Constructor Summary

Constructors

Constructor and Description
LOBFile(StorageFile lobFile) Constructs LOBFile.

Method Summary

Methods

Modifier and Type	Method and Description
(package private) void	close() Closes the file.
(package private) long	getFilePointer() Returns the current position of the file pointer.
(package private) StorageFile	getStorageFile() Get the StorageFile which represents the file where the contents of the LOB are stored.
(package private) long	length() Returns length of the file.
(package private) int	read(byte[] buff, int off, int len) Reads len number of bytes from the file starting from off position in the buffer.
(package private) int	readByte() Reads one byte from file.
(package private) void	seek(long pos) Sets the file pointer to a given position.
(package private) void	setLength(long size) Sets the file length to a given size.
(package private) void	write(byte[] buf) Writes a buffer completely into the file.
(package private) void	write(byte[] b, int off, int len) Writes a segment of bytes into the file.
(package private) void	write(int b) Writes one bytes into the file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

storageFile

private final StorageFile storageFile

The temporary file where the contents of the LOB should be stored.

randomAccessFile

private final StorageRandomAccessFile randomAccessFile

An object giving random access to storageFile.

Constructor Detail

LOBFile

LOBFile(StorageFile lobFile)
  throws java.io.FileNotFoundException

Constructs LOBFile.

Parameters:

lobFile - StorageFile object for which the file will be created

Throws:

java.io.FileNotFoundException - if the file exists but is a directory or cannot be opened

Method Detail

getStorageFile

StorageFile getStorageFile()

Get the StorageFile which represents the file where the contents of the LOB are stored.

Returns:

a StorageFile instance

length

long length()
      throws java.io.IOException

Returns length of the file.

Returns:

length of the file

Throws:

java.io.IOException - if an I/O error occurs

seek

void seek(long pos)
    throws java.io.IOException

Sets the file pointer to a given position.

Parameters:

pos - new position

Throws:

java.io.IOException - if an I/O error occurs

write

void write(int b)
     throws java.io.IOException,
            StandardException

Writes one bytes into the file.

Parameters:

b - int value of the byte

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

getFilePointer

long getFilePointer()
              throws java.io.IOException

Returns the current position of the file pointer.

Returns:

file pointer

Throws:

java.io.IOException - if an I/O error occurs

write

void write(byte[] b,
         int off,
         int len)
     throws java.io.IOException,
            StandardException

Writes a segment of bytes into the file.

Parameters:

b - byte array containing bytes to write into the file

off - starting position of segment

len - number of bytes to be written

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

readByte

int readByte()
       throws java.io.IOException,
              StandardException

Reads one byte from file.

Returns:

byte

Throws:

java.io.IOException - if disk operation fails

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

read

int read(byte[] buff,
       int off,
       int len)
   throws java.io.IOException,
          StandardException

Reads len number of bytes from the file starting from off position in the buffer.

Parameters:

buff - buffer

off - starting position of buffer

len - number of bytes

Returns:

number of bytes read

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

close

void close()
     throws java.io.IOException

Closes the file.

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

setLength

void setLength(long size)
         throws java.io.IOException,
                StandardException

Sets the file length to a given size.

Parameters:

size - new size

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException

write

void write(byte[] buf)
     throws java.io.IOException,
            StandardException

Writes a buffer completely into the file.

Parameters:

buf - buffer to write

Throws:

java.io.IOException - if an I/O error occurs

StandardException - it won't be thrown, it's in signature to allow subclasses to throw StandardException