freenet.support.io

Class BaseFileBucket

java.lang.Object

freenet.support.io.BaseFileBucket

All Implemented Interfaces:

Bucket, RandomAccessBucket

Direct Known Subclasses:

FileBucket, TempFileBucket

public abstract class BaseFileBucket
extends java.lang.Object
implements RandomAccessBucket

Field Summary

Fields

Modifier and Type	Field and Description
protected long	fileRestartCounter
static int	MAGIC
protected static java.lang.String	tempDir

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BaseFileBucket()
protected	BaseFileBucket(java.io.DataInputStream dis)
	BaseFileBucket(java.io.File file, boolean deleteOnExit) Constructor.

Method Summary

Modifier and Type	Method and Description
protected abstract boolean	createFileOnly() If true, we will fail if the file already exist.
protected void	deleteFile() Actually delete the underlying file.
protected abstract boolean	deleteOnExit()
protected abstract boolean	deleteOnFree()
void	free() Free the bucket, if supported.
void	free(boolean forceFree)
abstract java.io.File	getFile() Returns the file object this buckets data is kept in.
java.io.InputStream	getInputStream() Returns an InputStream that reads data from this Bucket.
java.io.InputStream	getInputStreamUnbuffered()
java.lang.String	getName() Returns a name for the bucket, may be used to identify them in certain in certain situations.
java.io.OutputStream	getOutputStream() Returns an OutputStream that is used to put data in this Bucket, from the beginning.
java.io.OutputStream	getOutputStreamUnbuffered() Get an OutputStream which is not buffered.
protected long	getPersistentTempID()
static java.lang.String	getTempDir() Return directory used for temp files.
protected java.io.File	getTempfile() Create a temporary file in the same directory as this file.
void	onResume(ClientContext context) Called after restarting.
protected void	setDeleteOnExit(java.io.File file)
static void	setTempDir(java.lang.String dirName) Set temp file directory.
long	size() Returns the amount of data currently in this bucket in bytes.
Bucket[]	split(int splitSize)
void	storeTo(java.io.DataOutputStream dos) Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException.
protected abstract boolean	tempFileAlreadyExists() If true, then the file is temporary and must already exist, so we will just open it.
LockableRandomAccessBuffer	toRandomAccessBuffer() Convert the Bucket to a LockableRandomAccessBuffer.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface freenet.support.api.RandomAccessBucket

createShadow

Methods inherited from interface freenet.support.api.Bucket

isReadOnly, setReadOnly

Field Detail

fileRestartCounter

protected long fileRestartCounter

tempDir

protected static java.lang.String tempDir

MAGIC

public static final int MAGIC

See Also:

Constant Field Values

Constructor Detail

BaseFileBucket

public BaseFileBucket(java.io.File file,
                      boolean deleteOnExit)

Constructor.

Parameters:

file -

deleteOnExit - If true, call File.deleteOnExit() on the file. WARNING: Delete on exit is a memory leak: The filenames are kept until the JVM exits, and cannot be removed even when the file has been deleted! It should only be used where it is ESSENTIAL! Note that if you want temp files to be deleted on exit, you also need to override deleteOnExit().

BaseFileBucket

protected BaseFileBucket()

BaseFileBucket

protected BaseFileBucket(java.io.DataInputStream dis)
                  throws java.io.IOException,
                         StorageFormatException

Throws:

java.io.IOException

StorageFormatException

Method Detail

setDeleteOnExit

protected void setDeleteOnExit(java.io.File file)

getOutputStreamUnbuffered

public java.io.OutputStream getOutputStreamUnbuffered()
                                               throws java.io.IOException

Description copied from interface: Bucket

Get an OutputStream which is not buffered. Should be called when we will buffer the stream at a higher level or when we will only be doing large writes (e.g. copying data from one Bucket to another). Does not make any more persistence guarantees than getOutputStream() does, this is just to save memory.

Specified by:

getOutputStreamUnbuffered in interface Bucket

Throws:

java.io.IOException

getOutputStream

public java.io.OutputStream getOutputStream()
                                     throws java.io.IOException

Description copied from interface: Bucket

Returns an OutputStream that is used to put data in this Bucket, from the beginning. It is not possible to append data to a Bucket! This simplifies the code significantly for some classes. If you need to append, just pass the OutputStream around. Will be buffered if appropriate (e.g. byte array backed buckets don't need to be buffered).

Specified by:

getOutputStream in interface Bucket

Throws:

java.io.IOException

tempFileAlreadyExists

protected abstract boolean tempFileAlreadyExists()

If true, then the file is temporary and must already exist, so we will just open it. Otherwise we will create a temporary file and then rename it over the target. Incompatible with createFileOnly()!

createFileOnly

protected abstract boolean createFileOnly()

If true, we will fail if the file already exist. Incompatible with tempFileAlreadyExists()!

deleteOnExit

protected abstract boolean deleteOnExit()

deleteOnFree

protected abstract boolean deleteOnFree()

getTempfile

protected java.io.File getTempfile()
                            throws java.io.IOException

Create a temporary file in the same directory as this file.

Throws:

java.io.IOException

getInputStreamUnbuffered

public java.io.InputStream getInputStreamUnbuffered()
                                             throws java.io.IOException

Specified by:

getInputStreamUnbuffered in interface Bucket

Throws:

java.io.IOException

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException

Description copied from interface: Bucket

Returns an InputStream that reads data from this Bucket. If there is no data in this bucket, null is returned. You have to call Closer.close(inputStream) on the obtained stream to prevent resource leakage.

Specified by:

getInputStream in interface Bucket

Throws:

java.io.IOException

getName

public java.lang.String getName()

Description copied from interface: Bucket

Returns a name for the bucket, may be used to identify them in certain in certain situations.

Specified by:

getName in interface Bucket

Returns:

the name of the file.

size

public long size()

Description copied from interface: Bucket

Returns the amount of data currently in this bucket in bytes.

Specified by:

size in interface Bucket

deleteFile

protected void deleteFile()

Actually delete the underlying file. Called by finalizer, will not be called twice. But length must still be valid when calling it.

getTempDir

public static java.lang.String getTempDir()

Return directory used for temp files.

setTempDir

public static void setTempDir(java.lang.String dirName)

Set temp file directory.

The directory must exist.

split

public Bucket[] split(int splitSize)

free

public void free()

Description copied from interface: Bucket

Free the bucket, if supported. Note that you must call free() even if you haven't used the Bucket (haven't called getOutputStream()) for some kinds of Bucket's, as they may have allocated space (e.g. created a temporary file).

Specified by:

free in interface Bucket

free

public void free(boolean forceFree)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getFile

public abstract java.io.File getFile()

Returns the file object this buckets data is kept in.

onResume

public void onResume(ClientContext context)
              throws ResumeFailedException

Description copied from interface: Bucket

Called after restarting. The Bucket should do any necessary housekeeping after resuming, e.g. registering itself with the appropriate persistent bucket tracker to avoid being garbage-collected. May be called twice, so the Bucket may need to track this internally.

Specified by:

onResume in interface Bucket

Parameters:

context - All the necessary runtime support will be on this object.

Throws:

ResumeFailedException

storeTo

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

Description copied from interface: Bucket

Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException. Used for recovering in emergencies, should be versioned if necessary.

Specified by:

storeTo in interface Bucket

Throws:

java.io.IOException

toRandomAccessBuffer

public LockableRandomAccessBuffer toRandomAccessBuffer()
                                                throws java.io.IOException

Description copied from interface: RandomAccessBucket

Convert the Bucket to a LockableRandomAccessBuffer. Must be efficient, i.e. will not copy the data. Freeing the Bucket is unnecessary if you free the LockableRandomAccessBuffer. Both the parent Bucket and the return value will be made read only.

Specified by:

toRandomAccessBuffer in interface RandomAccessBucket

Throws:

java.io.IOException

getPersistentTempID

protected long getPersistentTempID()