freenet.support.io

Class PooledFileRandomAccessBuffer

java.lang.Object

freenet.support.io.PooledFileRandomAccessBuffer

All Implemented Interfaces:

LockableRandomAccessBuffer, RandomAccessBuffer, java.io.Closeable, java.io.Serializable, java.lang.AutoCloseable

public class PooledFileRandomAccessBuffer
extends java.lang.Object
implements LockableRandomAccessBuffer, java.io.Serializable

Random access files with a limited number of open files, using a pool. LOCKING OPTIMISATION: Contention on DEFAULT_FDTRACKER likely here. It's not clear how to avoid that, FIXME. However, this is doing disk I/O (even if cached, system calls), so maybe it's not a big deal ... FIXME does this need a shutdown hook? I don't see why it would matter ... ???

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface freenet.support.api.LockableRandomAccessBuffer

LockableRandomAccessBuffer.RAFLock

Field Summary

Fields

Modifier and Type	Field and Description
java.io.File	file

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PooledFileRandomAccessBuffer()
	PooledFileRandomAccessBuffer(java.io.File file, boolean readOnly, long forceLength, java.util.Random seedRandom, long persistentTempID, boolean deleteOnFree) Create a RAF backed by a file.
	PooledFileRandomAccessBuffer(java.io.File file, java.lang.String mode, byte[] initialContents, int offset, int size, long persistentTempID, boolean deleteOnFree, boolean readOnly)

Method Summary

Modifier and Type	Method and Description
void	close()
protected void	closeRAF() Exposed for tests only.
boolean	equals(java.lang.Object obj) Must reimplement equals() as two PooledRAFWrapper's could well be the same storage object i.e.
void	free() Free the underlying resources.
int	hashCode() Must reimplement hashCode() if we change equals().
LockableRandomAccessBuffer.RAFLock	lockOpen() Keep the RAF open.
void	onResume(ClientContext context) Called on resuming, i.e.
void	pread(long fileOffset, byte[] buf, int bufOffset, int length) Read a block of data from a specific location in the file.
void	pwrite(long fileOffset, byte[] buf, int bufOffset, int length)
void	setSecureDelete(boolean secureDelete)
long	size()
void	storeTo(java.io.DataOutputStream dos) Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

file

public final java.io.File file

Constructor Detail

PooledFileRandomAccessBuffer

public PooledFileRandomAccessBuffer(java.io.File file,
                                    boolean readOnly,
                                    long forceLength,
                                    java.util.Random seedRandom,
                                    long persistentTempID,
                                    boolean deleteOnFree)
                             throws java.io.IOException

Create a RAF backed by a file.

Parameters:

file -

readOnly -

forceLength -

seedRandom -

persistentTempID - The tempfile ID, or -1.

Throws:

java.io.IOException

PooledFileRandomAccessBuffer

public PooledFileRandomAccessBuffer(java.io.File file,
                                    java.lang.String mode,
                                    byte[] initialContents,
                                    int offset,
                                    int size,
                                    long persistentTempID,
                                    boolean deleteOnFree,
                                    boolean readOnly)
                             throws java.io.IOException

Throws:

java.io.IOException

PooledFileRandomAccessBuffer

protected PooledFileRandomAccessBuffer()

Method Detail

size

public long size()

Specified by:

size in interface RandomAccessBuffer

pread

public void pread(long fileOffset,
                  byte[] buf,
                  int bufOffset,
                  int length)
           throws java.io.IOException

Description copied from interface: RandomAccessBuffer

Read a block of data from a specific location in the file. Guaranteed to read the whole range or to throw, like DataInputStream.readFully(). Must throw if the file is closed.

Specified by:

pread in interface RandomAccessBuffer

Parameters:

fileOffset - The offset within the file to read from.

buf - The buffer to write to.

bufOffset - The offset within the buffer to the first read byte.

length - The length of data to read.

Throws:

java.io.IOException - If we were unable to read the required number of bytes etc.

pwrite

public void pwrite(long fileOffset,
                   byte[] buf,
                   int bufOffset,
                   int length)
            throws java.io.IOException

Specified by:

pwrite in interface RandomAccessBuffer

Throws:

java.io.IOException

close

public void close()

Specified by:

close in interface RandomAccessBuffer

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

lockOpen

public LockableRandomAccessBuffer.RAFLock lockOpen()
                                            throws java.io.IOException

Description copied from interface: LockableRandomAccessBuffer

Keep the RAF open. Does not prevent others from writing to it. Will block until a slot is available if necessary. Hence can deadlock.

Specified by:

lockOpen in interface LockableRandomAccessBuffer

Throws:

java.io.IOException

closeRAF

protected void closeRAF()

Exposed for tests only. Used internally. Must be unlocked.

setSecureDelete

public void setSecureDelete(boolean secureDelete)

free

public void free()

Description copied from interface: RandomAccessBuffer

Free the underlying resources. May do nothing in some implementations. You should make sure the object can be GC'ed as well.

Specified by:

free in interface RandomAccessBuffer

onResume

public void onResume(ClientContext context)
              throws ResumeFailedException

Description copied from interface: LockableRandomAccessBuffer

Called on resuming, i.e. after serialization. Use to e.g. register with the list of temporary files.

Specified by:

onResume in interface LockableRandomAccessBuffer

Throws:

ResumeFailedException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

storeTo

public void storeTo(java.io.DataOutputStream dos)
             throws java.io.IOException

Description copied from interface: LockableRandomAccessBuffer

Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException. Used for recovering in emergencies, should be versioned if necessary. To make this work, write a fixed, unique integer magic value for the class, and add a clause to BucketTools.restoreRAFFrom().

Specified by:

storeTo in interface LockableRandomAccessBuffer

Throws:

java.io.IOException

hashCode

public int hashCode()

Description copied from interface: LockableRandomAccessBuffer

Must reimplement hashCode() if we change equals().

Specified by:

hashCode in interface LockableRandomAccessBuffer

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Must reimplement equals() as two PooledRAFWrapper's could well be the same storage object i.e. file on disk. This is particularly important during resuming a splitfile insert.

Specified by:

equals in interface LockableRandomAccessBuffer

Overrides:

equals in class java.lang.Object