uk.ac.gla.terrier.utility
Class Files

java.lang.Object
  uk.ac.gla.terrier.utility.Files

public class Files
extends java.lang.Object

Utililty class for opening readers/writers and input/output streams to files. Handles gzipped files on the fly, ie if a file ends in ".gz" or ".GZ", then it will be opened using a GZipInputStream/GZipOutputStream. All returned Streams, Readers, Writers etc are Buffered. If a charset encoding is not specified, then the system default is used. New interfaces are used to descibe random data access.

FileSystem plugsin

Additional file systems can be plugged into this module, by calling the addFileSystemCapability() method. FileSystems have read and/or write capabilities, as specified using the FSCapability constants. Files using these external file systems should be denoted by scheme prefixes - eg ftp://, http:// etc. NB: file:// is the default scheme

Nested Class Summary

static interface

Files.FSCapability constants declaring which capabilites a file system has

Constructor Summary

Files()

Method Summary

static void	addFileSystemCapability(FileSystem fs) Add a file system to Terrier.
static void	addPathTransormation(java.lang.String find, java.lang.String replace) add a static transformation to apply to a path.
static boolean	canRead(java.lang.String filename) returns true iff path can be read
static boolean	canWrite(java.lang.String filename) returns true iff path can be read
static java.lang.Long	copyFile(java.io.File srcFile, java.io.File destFile) Copy a file from srcFile to destFile.
static java.lang.Long	copyFile(java.io.InputStream in, java.io.OutputStream out) Copy all bytes from in to out
static java.lang.Long	copyFile(java.lang.String srcFilename, java.lang.String destFilename) Copy a file from srcFile to destFile.
static java.lang.Long	createChecksum(java.io.File file) Returns the CRC checksum of denoted file
static boolean	delete(java.lang.String filename) Delete the named file.
static boolean	deleteOnExit(java.lang.String path) Mark the named path as to be deleted on exit.
static boolean	exists(java.lang.String path) returns true iff the path is really a path
static java.lang.String	getFileSystemName(java.lang.String path) Get the name of the file system that would be used to access a given file or directory.
static java.lang.String	getParent(java.lang.String path) What is the parent path to the specified path?
static boolean	isDirectory(java.lang.String path) return true if path is a directory
static long	length(java.io.File f) returns the length of file f
static long	length(java.lang.String filename) returns the length of the file, or 0L if cannot be found etc
static java.lang.String[]	list(java.lang.String path) List the contents of a directory
static boolean	mkdir(java.lang.String path) returns true if the specificed path can be made as a directory
static RandomDataInput	openFileRandom(java.io.File file) Open a file for random access reading
static RandomDataInput	openFileRandom(java.lang.String filename) Returns a RandomAccessFile implementation accessing the specificed file
static java.io.BufferedReader	openFileReader(java.io.File file) Opens a reader to the file called file.
static java.io.BufferedReader	openFileReader(java.io.File file, java.lang.String charset) Opens a reader to the file called filename.
static java.io.BufferedReader	openFileReader(java.lang.String filename) Opens a reader to the file called filename.
static java.io.BufferedReader	openFileReader(java.lang.String filename, java.lang.String charset) Opens a reader to the file called filename.
static java.io.InputStream	openFileStream(java.io.File file) Opens an InputStream to a file called file.
static java.io.InputStream	openFileStream(java.lang.String filename) Opens an InputStream to a file called filename.
static boolean	rename(java.lang.String sourceFilename, java.lang.String destFilename) rename a file or directory.
static RandomDataOutput	writeFileRandom(java.io.File file) Open a file for random access writing and reading
static RandomDataOutput	writeFileRandom(java.lang.String filename) Returns a RandomAccessFile implementation accessing the specificed file
static java.io.OutputStream	writeFileStream(java.io.File file) Opens an OutputStream to a file called file.
static java.io.OutputStream	writeFileStream(java.lang.String filename) Opens an OutputStream to a file called filename.
static java.io.Writer	writeFileWriter(java.io.File file) Opens an Writer to a file called file.
static java.io.Writer	writeFileWriter(java.io.File file, java.lang.String charset) Opens an Writer to a file called file.
static java.io.Writer	writeFileWriter(java.lang.String filename) Opens an Writer to a file called file.
static java.io.Writer	writeFileWriter(java.lang.String filename, java.lang.String charset) Opens an Writer to a file called file.

Methods inherited from class java.lang.Object

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

Constructor Detail

Files

public Files()

Method Detail

addPathTransormation

public static void addPathTransormation(java.lang.String find,
                                        java.lang.String replace)

add a static transformation to apply to a path. Find and replace are both regular expressions

addFileSystemCapability

public static void addFileSystemCapability(FileSystem fs)

Add a file system to Terrier. File systems are denoted by URI scheme prefixes (e.g. http). The underlying file system is represented by an FileSystem

getFileSystemName

public static java.lang.String getFileSystemName(java.lang.String path)

Get the name of the file system that would be used to access a given file or directory.

Parameters:

path -

Returns:

name Name of the file system, or null if no filesystem found

openFileRandom

public static RandomDataInput openFileRandom(java.lang.String filename)
                                      throws java.io.IOException

Returns a RandomAccessFile implementation accessing the specificed file

Throws:

java.io.IOException

writeFileRandom

public static RandomDataOutput writeFileRandom(java.lang.String filename)
                                        throws java.io.IOException

Returns a RandomAccessFile implementation accessing the specificed file

Throws:

java.io.IOException

delete

public static boolean delete(java.lang.String filename)

Delete the named file. Returns false if the scheme of filename cannot be recognised, the filesystem doesnt have write capability, or the underlying filesystem could not delete the file

Parameters:

filename - path to file to delete

deleteOnExit

public static boolean deleteOnExit(java.lang.String path)

Mark the named path as to be deleted on exit. Returns false if the scheme of the filename cannot be recognised, the filesystem does not have write capability, or the file system does not have deleteOnExit capability

exists

public static boolean exists(java.lang.String path)

returns true iff the path is really a path

canRead

public static boolean canRead(java.lang.String filename)

returns true iff path can be read

canWrite

public static boolean canWrite(java.lang.String filename)

returns true iff path can be read

mkdir

public static boolean mkdir(java.lang.String path)

returns true if the specificed path can be made as a directory

length

public static long length(java.lang.String filename)

returns the length of the file, or 0L if cannot be found etc

isDirectory

public static boolean isDirectory(java.lang.String path)

return true if path is a directory

rename

public static boolean rename(java.lang.String sourceFilename,
                             java.lang.String destFilename)

rename a file or directory. If the two are on different file systems, it is assumed to be a file

getParent

public static java.lang.String getParent(java.lang.String path)

What is the parent path to the specified path?

list

public static java.lang.String[] list(java.lang.String path)

List the contents of a directory

openFileReader

public static java.io.BufferedReader openFileReader(java.io.File file)
                                             throws java.io.IOException

Opens a reader to the file called file. Provided for easy overriding for encoding support etc in child classes. Called from openNextFile().

Parameters:

file - File to open.

Returns:

BufferedReader of the file

Throws:

java.io.IOException

openFileReader

public static java.io.BufferedReader openFileReader(java.io.File file,
                                                    java.lang.String charset)
                                             throws java.io.IOException

Opens a reader to the file called filename. Provided for easy overriding for encoding support etc in child classes. Called from openNextFile().

Parameters:

file - File to open.

charset - Character set encoding of file. null for system default.

Returns:

BufferedReader of the file

Throws:

java.io.IOException

openFileReader

public static java.io.BufferedReader openFileReader(java.lang.String filename)
                                             throws java.io.IOException

Opens a reader to the file called filename. Provided for easy overriding for encoding support etc in child classes. Called from openNextFile().

Parameters:

filename - File to open.

Returns:

BufferedReader of the file

Throws:

java.io.IOException

openFileReader

public static java.io.BufferedReader openFileReader(java.lang.String filename,
                                                    java.lang.String charset)
                                             throws java.io.IOException

Opens a reader to the file called filename. Provided for easy overriding for encoding support etc in child classes. Called from openNextFile().

Parameters:

filename - File to open.

charset - Character set encoding of file. null for system default.

Returns:

BufferedReader of the file

Throws:

java.io.IOException

openFileStream

public static java.io.InputStream openFileStream(java.io.File file)
                                          throws java.io.IOException

Opens an InputStream to a file called file.

Parameters:

file - File to open.

Returns:

InputStream of the file

Throws:

java.io.IOException

openFileRandom

public static RandomDataInput openFileRandom(java.io.File file)
                                      throws java.io.IOException

Open a file for random access reading

Throws:

java.io.IOException

openFileStream

public static java.io.InputStream openFileStream(java.lang.String filename)
                                          throws java.io.IOException

Opens an InputStream to a file called filename.

Parameters:

filename - File to open.

Returns:

InputStream of the file

Throws:

java.io.IOException

writeFileStream

public static java.io.OutputStream writeFileStream(java.io.File file)
                                            throws java.io.IOException

Opens an OutputStream to a file called file.

Parameters:

file - File to open.

Returns:

OutputStream of the file

Throws:

java.io.IOException

writeFileRandom

public static RandomDataOutput writeFileRandom(java.io.File file)
                                        throws java.io.IOException

Open a file for random access writing and reading

Throws:

java.io.IOException

writeFileStream

public static java.io.OutputStream writeFileStream(java.lang.String filename)
                                            throws java.io.IOException

Opens an OutputStream to a file called filename.

Parameters:

filename - File to open.

Returns:

OutputStream of the file

Throws:

java.io.IOException

writeFileWriter

public static java.io.Writer writeFileWriter(java.io.File file)
                                      throws java.io.IOException

Opens an Writer to a file called file. System default encoding will be used.

Parameters:

file - File to open.

Returns:

Writer of the file

Throws:

java.io.IOException

writeFileWriter

public static java.io.Writer writeFileWriter(java.io.File file,
                                             java.lang.String charset)
                                      throws java.io.IOException

Opens an Writer to a file called file.

Parameters:

file - File to open.

charset - Character set encoding of file. null for system default.

Returns:

Writer of the file

Throws:

java.io.IOException

writeFileWriter

public static java.io.Writer writeFileWriter(java.lang.String filename)
                                      throws java.io.IOException

Opens an Writer to a file called file. System default encoding will be used.

Parameters:

filename - File to open.

Returns:

Writer of the file

Throws:

java.io.IOException

writeFileWriter

public static java.io.Writer writeFileWriter(java.lang.String filename,
                                             java.lang.String charset)
                                      throws java.io.IOException

Opens an Writer to a file called file.

Parameters:

filename - File to open.

charset - Character set encoding of file. null for system default.

Returns:

Writer of the file

Throws:

java.io.IOException

copyFile

public static java.lang.Long copyFile(java.lang.String srcFilename,
                                      java.lang.String destFilename)
                               throws java.io.IOException

Copy a file from srcFile to destFile.

Returns:

null if OK

Throws:

java.io.IOException - if there was a problem copying

copyFile

public static java.lang.Long copyFile(java.io.File srcFile,
                                      java.io.File destFile)
                               throws java.io.IOException

Copy a file from srcFile to destFile.

Returns:

null if OK

Throws:

java.io.IOException - if there was a problem copying

copyFile

public static java.lang.Long copyFile(java.io.InputStream in,
                                      java.io.OutputStream out)
                               throws java.io.IOException

Copy all bytes from in to out

Returns:

null if OK throws IOException if there was a problem copying

Throws:

java.io.IOException

createChecksum

public static java.lang.Long createChecksum(java.io.File file)
                                     throws java.io.IOException

Returns the CRC checksum of denoted file

Throws:

java.io.IOException

length

public static long length(java.io.File f)

returns the length of file f