com.continuent.tungsten.common.file
Class FileIO

java.lang.Object
  com.continuent.tungsten.common.file.FileIO

public class FileIO
extends java.lang.Object

Implements simple utility methods for storing and retrieving files located under a base directory. This class is designed to support operations on both standard Linux file systems as well as Hadoop. For this reason we use the package-defined FileIOException as a covering exception for all underlying exception types instead of exceptions like IOException that only apply to on particular type of file system.

Nested Class Summary

class

FileIO.LocalFilenameFilter Internal filter class to select file names based on a prefix.

Constructor Summary

FileIO()

Method Summary

boolean	delete(FilePath path) Delete path.
boolean	delete(FilePath path, boolean recursive) Delete path and optionally any children.
boolean	exists(FilePath path) Returns true if path exists.
boolean	isDirectory(FilePath path) Returns true if path is a directory.
boolean	isFile(FilePath path) Returns true if path is an ordinary file.
java.lang.String[]	list(FilePath path) Return a list of the names of children of this path.
java.lang.String[]	list(FilePath path, java.lang.String prefix) Return a list of the names of children of this path that start with the given prefix.
boolean	mkdir(FilePath path) Create path as a new directory.
boolean	mkdirs(FilePath path) Create path as a new directory including any intervening directories in the path.
java.lang.String	read(FilePath path) Returns the value of the contents of a file as a string using UTF-8 as charset encoding.
java.lang.String	read(FilePath path, java.lang.String charset) Returns the value of the contents of a file as a string.
boolean	readable(FilePath path) Returns true if path is readable.
boolean	writable(FilePath path) Returns true if path is writable.
void	write(FilePath path, java.lang.String value) Write data to file system using UTF-8 charset for file encoding and with flush only.
void	write(FilePath path, java.lang.String value, java.lang.String charset) Write data to file system with flush only.
void	write(FilePath path, java.lang.String value, java.lang.String charset, boolean fsync) Writes a string into a file, replacing an existing contents.

Methods inherited from class java.lang.Object

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

Constructor Detail

FileIO

public FileIO()

Method Detail

exists

public boolean exists(FilePath path)

Returns true if path exists.

isFile

public boolean isFile(FilePath path)

Returns true if path is an ordinary file.

isDirectory

public boolean isDirectory(FilePath path)

Returns true if path is a directory.

writable

public boolean writable(FilePath path)

Returns true if path is writable.

readable

public boolean readable(FilePath path)

Returns true if path is readable.

list

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

Return a list of the names of children of this path.

Parameters:

path - Path to search

Returns:

An array of path names, which will be empty if there are no children

list

public java.lang.String[] list(FilePath path,
                               java.lang.String prefix)

Return a list of the names of children of this path that start with the given prefix.

Parameters:

path - Path to search

prefix - Required file name prefix or null to return all children

Returns:

An array of path names, which will be empty if there are no children

mkdir

public boolean mkdir(FilePath path)

Create path as a new directory.

Parameters:

path - Path to create

Returns:

true if successful

mkdirs

public boolean mkdirs(FilePath path)

Create path as a new directory including any intervening directories in the path.

Parameters:

path - Path to create

Returns:

true if successful

delete

public boolean delete(FilePath path)

Delete path. This form ignored children.

Parameters:

path - Path to delete

Returns:

true if fully successful, otherwise false.

delete

public boolean delete(FilePath path,
                      boolean recursive)

Delete path and optionally any children. Recursive deletes fail if we cannot delete all children as well as the original path.

Parameters:

path - Path to delete

recursive - If true delete child files/directories as well

Returns:

true if fully successful, otherwise false.

write

public void write(FilePath path,
                  java.lang.String value)
           throws FileIOException

Write data to file system using UTF-8 charset for file encoding and with flush only.

Parameters:

path - The file path

value - The string to write in the file

Throws:

FileIOException - Thrown if file is not writable

write

public void write(FilePath path,
                  java.lang.String value,
                  java.lang.String charset)
           throws FileIOException

Write data to file system with flush only.

Parameters:

path - The file path

value - The string to write in the file

charset - Character set of file data (e.g., UTF-8)

Throws:

FileIOException - Thrown if file is not writable

write

public void write(FilePath path,
                  java.lang.String value,
                  java.lang.String charset,
                  boolean fsync)
           throws FileIOException

Writes a string into a file, replacing an existing contents. There are two durability options. If fsync is true, we issue the Java equivalent of fsync, which is generally sufficient to survive a file system crash. If fsync is false, we just flush, which will generally survive a process crash.

Parameters:

path - The file path

value - The string to write in the file

charset - Character set of file data (e.g., UTF-8)

fsync - If true issue an fsync, otherwise just flush

Throws:

FileIOException - Thrown if file is not writable

read

public java.lang.String read(FilePath path)
                      throws FileIOException

Returns the value of the contents of a file as a string using UTF-8 as charset encoding.

Parameters:

path - The file path

Returns:

Contents of the file, which is an empty string for a 0-length file

Throws:

FileIOException - Thrown if file is not readable

read

public java.lang.String read(FilePath path,
                             java.lang.String charset)
                      throws FileIOException

Returns the value of the contents of a file as a string.

Parameters:

path - The file path

charset - Character set of file data (e.g., UTF-8)

Returns:

Contents of the file, which is an empty string for a 0-length file

Throws:

FileIOException - Thrown if file is not readable