org.neo4j.io.pagecache

Interface FileHandle

public interface FileHandle

A handle to a file as seen by the page cache. The file may or may not be mapped.

See Also:

PageCache.streamFilesRecursive(File)

Field Summary

Fields

Modifier and Type	Field and Description
static Consumer<FileHandle>	HANDLE_DELETE Useful consumer when doing deletion in stream pipeline.

Method Summary

Modifier and Type	Method and Description
void	delete() Delete the file that this file handle represents.
File	getFile() Get a File object for the abstract path name that this file handle represents.
static Consumer<FileHandle>	handleRenameBetweenDirectories(File from, File to) Create a consumer of FileHandle that uses fileHandle.rename to move file held by file handle to move from directory to directory.
void	rename(File to, CopyOption... options) Rename source file to the given target file, effectively moving the file from source to target.

Field Detail

HANDLE_DELETE

static final Consumer<FileHandle> HANDLE_DELETE

Useful consumer when doing deletion in stream pipeline.

Possible IOException caused by fileHandle.delete() is wrapped in UncheckedIOException

Method Detail

handleRenameBetweenDirectories

static Consumer<FileHandle> handleRenameBetweenDirectories(File from,
                                                           File to)

Create a consumer of FileHandle that uses fileHandle.rename to move file held by file handle to move from directory to directory.

Possibly IOException will be wrapped in UncheckedIOException

Parameters:

from - Directory to move file from.

to - Directory to move file to.

Returns:

A new Consumer that moves the file wrapped by the file handle.

getFile

File getFile()

Get a File object for the abstract path name that this file handle represents. Note that the File is not guaranteed to support any operations other than querying the path name. For instance, to delete the file you have to use the delete() method of this file handle, instead of File.delete().

Returns:

A File for this file handle.

rename

void rename(File to,
            CopyOption... options)
     throws IOException

Rename source file to the given target file, effectively moving the file from source to target. Both files have to be unmapped when performing the rename, otherwise an exception will be thrown. If the file is moved to a path where some of the directories of the path don't already exists, then those missing directories will be created prior to the move. This is not an atomic operation, and an exception may be thrown if the a directory in the path is deleted concurrently with the file rename operation. Likewise, if the file rename causes a directory to become empty, then those directories will be deleted automatically. This operation is also not atomic, so if files are added to such directories concurrently with the rename operation, then an exception can be thrown.

Parameters:

to - The new name of the file after the rename.

options - Options to modify the behaviour of the move in possibly platform specific ways. In particular, StandardCopyOption.REPLACE_EXISTING may be used to overwrite any existing file at the target path name, instead of throwing an exception.

Throws:

org.neo4j.io.pagecache.impl.FileIsMappedException - if either the file represented by this file handle is mapped, or the target file is mapped.

FileAlreadyExistsException - if the target file already exists, and the StandardCopyOption.REPLACE_EXISTING open option was not specified.

IOException - if an I/O error occurs, for instance when canonicalising the to path.

delete

void delete()
     throws IOException

Delete the file that this file handle represents.

Throws:

org.neo4j.io.pagecache.impl.FileIsMappedException - if this file is mapped by the page cache.

NoSuchFileException - if the underlying file was deleted after this handle was created.

IOException - if an I/O error occurs.