ch.javasoft.jbase
Class RandomAccessFilePersistor

java.lang.Object
  ch.javasoft.jbase.RandomAccessFilePersistor

All Implemented Interfaces:

Stateful, RandomAccessPersister

public class RandomAccessFilePersistor
extends Object
implements RandomAccessPersister

The RandomAccessFilePersistor implements RandomAccessPersister using RandomAccessFiles.

Constructor Summary

	RandomAccessFilePersistor(File file)
protected	RandomAccessFilePersistor(File file, RandomAccessFile raf)
	RandomAccessFilePersistor(File folder, String fileName)

Method Summary

void	close(boolean erase) Closes this persistor, subsequent read or write calls will cause an exception.
RandomAccessFilePersistor	createReadCopy(ReadWriteLock lock) Returns a copy of this persistor for read access.
void	flush() Ensures that any possibly cached data is written to the underlying store
DataInput	getInput() Returns a data input object to read from.
DataOutput	getOutput() Returns a data input object to write to.
long	getPosition() Returns the current byte position.
void	setLength(long byteLength) Sets the length of the storage.
void	setPosition(long bytePos) Sets the byte offset position.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomAccessFilePersistor

public RandomAccessFilePersistor(File folder,
                                 String fileName)
                          throws FileNotFoundException

Throws:

FileNotFoundException

RandomAccessFilePersistor

public RandomAccessFilePersistor(File file)
                          throws FileNotFoundException

Throws:

FileNotFoundException

RandomAccessFilePersistor

protected RandomAccessFilePersistor(File file,
                                    RandomAccessFile raf)
                             throws FileNotFoundException

Throws:

FileNotFoundException

Method Detail

getPosition

public long getPosition()
                 throws IOException

Description copied from interface: RandomAccessPersister

Returns the current byte position. Note that any read or write operation increments the position.

Specified by:

getPosition in interface RandomAccessPersister

Throws:

IOException

setPosition

public void setPosition(long bytePos)
                 throws IOException

Description copied from interface: RandomAccessPersister

Sets the byte offset position. Subsequent read or write operations start at the specified position, even if it is after the actual length of the file or store. However, the length does not change before actually writing at this position.

Specified by:

setPosition in interface RandomAccessPersister

Throws:

IOException

setLength

public void setLength(long byteLength)
               throws IOException

Description copied from interface: RandomAccessPersister

Sets the length of the storage. If this is shorter than the current length, the data will be truncated. If it is after the current length, additional data is appended, but its content is undefined.

Specified by:

setLength in interface RandomAccessPersister

Throws:

IOException

flush

public void flush()
           throws IOException

Description copied from interface: RandomAccessPersister

Ensures that any possibly cached data is written to the underlying store

Specified by:

flush in interface RandomAccessPersister

Throws:

IOException

close

public void close(boolean erase)
           throws IOException

Description copied from interface: RandomAccessPersister

Closes this persistor, subsequent read or write calls will cause an exception. Multiple close calls, however, do not cause any exceptions.

Specified by:

close in interface RandomAccessPersister

Parameters:

erase - if true, underlying files are deleted upon close

Throws:

IOException

getInput

public DataInput getInput()
                   throws IOException

Description copied from interface: RandomAccessPersister

Returns a data input object to read from. Read operations increment the current byte position

Specified by:

getInput in interface RandomAccessPersister

Throws:

IOException

getOutput

public DataOutput getOutput()
                     throws IOException

Description copied from interface: RandomAccessPersister

Returns a data input object to write to. Write operations increment the current byte position

Specified by:

getOutput in interface RandomAccessPersister

Throws:

IOException

createReadCopy

public RandomAccessFilePersistor createReadCopy(ReadWriteLock lock)
                                         throws IOException

Returns a copy of this persistor for read access. The new reader is opened and the position is set to this persistor's position. The returned instance does not support write operations, thus, invoking getOutput() or setLength(long) causes an UnsupportedOperationException.

Specified by:

createReadCopy in interface Stateful

Specified by:

createReadCopy in interface RandomAccessPersister

Parameters:

lock - A read/write lock, the write lock is held. The lock, however, might also be used for other functionality of the returned read copy, for instance, if the read copy has to be put in sync with the main object.

Returns:

a new read copy instance, with copied state compared to other read copy instances

Throws:

IOException

See Also:

Stateful.createReadCopy(ReadWriteLock)