Package com.yahoo.io

Class IOUtils

java.lang.Object

com.yahoo.io.IOUtils

public abstract class IOUtils
extends Object

Some static io convenience methods.

Author:

bratseth, Bjorn Borud

Constructor Summary

Constructors

Constructor	Description
IOUtils()

Method Summary

Modifier and Type	Method	Description
static void	closeAll(List<Reader> readers)	Convenience method for closing a list of readers.
static void	closeInputStream(InputStream stream)	Closes an input stream, or does nothing if the stream is null
static void	closeOutputStream(OutputStream stream)	Closes an output stream, or does nothing if the stream is null
static void	closeReader(Reader reader)	Closes a reader, or does nothing if the reader is null
static void	closeWriter(Writer writer)	Closes a writer, or does nothing if the writer is null
static void	copy(File inFile, File outFile)	Copies a file to another file.
static void	copy(String inFile, String outFile)	Copies a file to another file.
static void	copy(String inFile, String outFile, int lineCount)	Copies the n first lines of a file to another file.
static void	copyDirectory(File sourceLocation, File targetLocation)	Copies all files and subdirectories (infinitely recursively) in a directory to another.
static void	copyDirectory(File sourceLocation, File targetLocation, int maxRecurseLevel)	Copies all files and subdirectories in a directory to another.
static void	copyDirectory(File sourceLocation, File targetLocation, int maxRecurseLevel, FilenameFilter filter)	Copies all files and subdirectories in a directory to another.
static void	copyDirectoryInto(File sourceLocation, File targetLocation)	Copies the whole source directory (infinitely recursively) into the target directory.
static int	countLines(String file)	Returns the number of lines in a file.
static void	createDirectory(String filename)	Creates the directory path of this file if it does not exist
static BufferedReader	createReader(File filename, String encoding)	Creates a buffered reader
static BufferedReader	createReader(String filename)	Creates a buffered reader in the default encoding
static BufferedReader	createReader(String filename, String encoding)	Creates a buffered reader
static BufferedWriter	createWriter(File file, boolean append)	Creates a buffered writer in the default encoding
static BufferedWriter	createWriter(File file, String encoding, boolean append)	Creates a buffered writer, and the directories to contain it if they do not exist
static BufferedWriter	createWriter(String filename, boolean append)	Creates a buffered writer in the default encoding
static BufferedWriter	createWriter(String filename, String encoding, boolean append)	Creates a buffered writer, and the directories to contain it if they do not exist
static List<String>	getLines(String fileName)	Returns a list containing the lines in the given file as strings
static String	readAll(InputStream stream, Charset charset)	Read an input stream completely into a string
static String	readAll(Reader reader)	Reads all data from a reader into a string.
static byte[]	readBytes(InputStream stream, int chunkSize)	Reads all the content of the given input stream, in chunks of at max chunkSize
static String	readFile(File file)	Reads the contents of a UTF-8 text file into a String.
static byte[]	readFileBytes(File file)	Reads the content of a file into a byte array
static boolean	recursiveDeleteDir(File dir)	Recursive deletion of directories
static ByteBuffer	utf8ByteBuffer(String s)	Encodes string as UTF-8 into ByteBuffer
static void	writeFile(File file, byte[] content)	Writes the given content to the file (replacing any existing content)
static void	writeFile(File file, String text, boolean append)	Writes the given string to the file
static void	writeFile(String file, String text, boolean append)	Writes the given string to the file

Methods inherited from class java.lang.Object

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

Constructor Details

IOUtils

public IOUtils()

Method Details

closeWriter

public static void closeWriter(Writer writer)

Closes a writer, or does nothing if the writer is null

closeReader

public static void closeReader(Reader reader)

Closes a reader, or does nothing if the reader is null

closeInputStream

public static void closeInputStream(InputStream stream)

Closes an input stream, or does nothing if the stream is null

closeOutputStream

public static void closeOutputStream(OutputStream stream)

Closes an output stream, or does nothing if the stream is null

createReader

public static BufferedReader createReader(File filename,
 String encoding)
                                   throws IOException

Creates a buffered reader

Parameters:

filename - the name or path of the file

encoding - the encoding of the file, for instance "UTF-8"

Throws:

IOException

createReader

public static BufferedReader createReader(String filename,
 String encoding)
                                   throws IOException

Creates a buffered reader

Parameters:

filename - the name or path of the file

encoding - the encoding of the file, for instance "UTF-8"

Throws:

IOException

createReader

public static BufferedReader createReader(String filename)
                                   throws IOException

Creates a buffered reader in the default encoding

Throws:

IOException

createWriter

public static BufferedWriter createWriter(String filename,
 String encoding,
 boolean append)
                                   throws IOException

Creates a buffered writer, and the directories to contain it if they do not exist

Parameters:

filename - the name or path of the file

encoding - the encoding to use, for instance "UTF-8"

append - whether to append to the files if it exists

Throws:

IOException

createWriter

public static BufferedWriter createWriter(File file,
 String encoding,
 boolean append)
                                   throws IOException

Creates a buffered writer, and the directories to contain it if they do not exist

Parameters:

file - the file to write to

encoding - the encoding to use, for instance "UTF-8"

append - whether to append to the files if it exists

Throws:

IOException

createWriter

public static BufferedWriter createWriter(String filename,
 boolean append)
                                   throws IOException

Creates a buffered writer in the default encoding

Parameters:

filename - the name or path of the file

append - whether to append to the files if it exists

Throws:

IOException

createWriter

public static BufferedWriter createWriter(File file,
 boolean append)
                                   throws IOException

Creates a buffered writer in the default encoding

Parameters:

file - the file to write to

append - whether to append to the files if it exists

Throws:

IOException

createDirectory

public static void createDirectory(String filename)

Creates the directory path of this file if it does not exist

copy

public static void copy(String inFile,
 String outFile,
 int lineCount)
                 throws IOException

Copies the n first lines of a file to another file. If the out file exists it will be overwritten

Throws:

IOException - if copying fails

copy

public static void copy(String inFile,
 String outFile)
                 throws IOException

Copies a file to another file. If the out file exists it will be overwritten.

Throws:

IOException - if copying fails

copy

public static void copy(File inFile,
 File outFile)
                 throws IOException

Copies a file to another file. If the out file exists it will be overwritten.

Throws:

IOException

copyDirectory

public static void copyDirectory(File sourceLocation,
 File targetLocation,
 int maxRecurseLevel)
                          throws IOException

Copies all files and subdirectories in a directory to another. Any existing files are overwritten.

Parameters:

sourceLocation - the source directory

targetLocation - the target directory

maxRecurseLevel - if this is 1, only files immediately in sourceLocation are copied, if it is 2, then files contained in immediate subdirectories are copied, etc. If it is 0, sourceLocation will only be copied if it is a file, not a directory. If it is negative, recursion is infinite.

Throws:

IOException - if copying any file fails. This will typically result in some files being copied and others not, i.e this method is not exception safe

copyDirectory

public static void copyDirectory(File sourceLocation,
 File targetLocation,
 int maxRecurseLevel,
 FilenameFilter filter)
                          throws IOException

Copies all files and subdirectories in a directory to another. Any existing files are overwritten.

Parameters:

sourceLocation - the source directory

targetLocation - the target directory

maxRecurseLevel - if this is 1, only files immediately in sourceLocation are copied, if it is 2, then files contained in immediate subdirectories are copied, etc. If it is 0, sourceLocation will only be copied if it is a file, not a directory. If it is negative, recursion is infinite.

filter - Only copy files passing through filter.

Throws:

IOException - if copying any file fails. This will typically result in some files being copied and others not, i.e this method is not exception safe

copyDirectory

public static void copyDirectory(File sourceLocation,
 File targetLocation)
                          throws IOException

Copies all files and subdirectories (infinitely recursively) in a directory to another. Any existing files are overwritten.

Parameters:

sourceLocation - the source directory

targetLocation - the target directory

Throws:

IOException - if copying any file fails. This will typically result in some files being copied and others not, i.e this method is not exception safe

copyDirectoryInto

public static void copyDirectoryInto(File sourceLocation,
 File targetLocation)
                              throws IOException

Copies the whole source directory (infinitely recursively) into the target directory.

Throws:

IOException - if copying any file fails. This will typically result in some files being copied and others not, i.e this method is not exception safe

countLines

public static int countLines(String file)

Returns the number of lines in a file. If the file does not exists, 0 is returned

getLines

public static List<String> getLines(String fileName)
                             throws IOException

Returns a list containing the lines in the given file as strings

Returns:

a list of Strings for the lines of the file, in order

Throws:

IOException - if the file could not be read

recursiveDeleteDir

public static boolean recursiveDeleteDir(File dir)

Recursive deletion of directories

utf8ByteBuffer

public static ByteBuffer utf8ByteBuffer(String s)

Encodes string as UTF-8 into ByteBuffer

readFile

public static String readFile(File file)
                       throws IOException

Reads the contents of a UTF-8 text file into a String.

Parameters:

file - the file to read, or null

Returns:

the file content as a string, or null if the input file was null

Throws:

IOException

readBytes

public static byte[] readBytes(InputStream stream,
 int chunkSize)
                        throws IOException

Reads all the content of the given input stream, in chunks of at max chunkSize

Throws:

IOException

readFileBytes

public static byte[] readFileBytes(File file)
                            throws IOException

Reads the content of a file into a byte array

Throws:

IOException

readAll

public static String readAll(Reader reader)
                      throws IOException

Reads all data from a reader into a string. Uses a buffer to speed up reading.

Throws:

IOException

readAll

public static String readAll(InputStream stream,
 Charset charset)
                      throws IOException

Read an input stream completely into a string

Throws:

IOException

closeAll

public static void closeAll(List<Reader> readers)

Convenience method for closing a list of readers. Does nothing if the given reader list is null.

writeFile

public static void writeFile(File file,
 String text,
 boolean append)
                      throws IOException

Writes the given string to the file

Throws:

IOException

writeFile

public static void writeFile(File file,
 byte[] content)
                      throws UncheckedIOException

Writes the given content to the file (replacing any existing content)

Throws:

UncheckedIOException

writeFile

public static void writeFile(String file,
 String text,
 boolean append)
                      throws IOException

Writes the given string to the file

Throws:

IOException