org.apache.juneau.internal

Class IOUtils

java.lang.Object

org.apache.juneau.internal.IOUtils

public final class IOUtils
extends Object

Various I/O related utility methods.

Field Summary

Fields

Modifier and Type	Field and Description
static Charset	UTF8 UTF-8 charset

Constructor Summary

Constructors

Constructor and Description
IOUtils()

Method Summary

Modifier and Type	Method and Description
static void	close(Object... o) Close all specified input streams, output streams, readers, and writers.
static void	closeQuietly(InputStream is) Close input stream and ignore any exceptions.
static void	closeQuietly(Object... o) Quietly close all specified input streams, output streams, readers, and writers.
static void	closeQuietly(OutputStream os) Close output stream and ignore any exceptions.
static void	closeQuietly(Reader r) Close reader and ignore any exceptions.
static void	closeQuietly(Writer w) Close writer and ignore any exceptions.
static long	count(InputStream is) Counts the number of bytes in the input stream and then closes the stream.
static long	count(Reader r) Counts the number of characters in the reader and then closes the reader.
static void	flush(Object... o) Flushes multiple output streams and writers in a single call.
static Reader	getBufferedReader(Reader r) Wraps the specified reader in a buffered reader.
static int	getBufferSize(String contentLength) Given the specified "Content-Length" header value, return an appropriate buffer size.
static void	pipe(InputStream in, OutputStream out) Pipes the contents of the specified streams.
static void	pipe(Object in, OutputStream out) Pipes the contents of the specified object into the output stream.
static void	pipe(Object in, Writer out) Pipes the contents of the specified object into the writer.
static void	pipe(Reader in, Writer out) Pipes the contents of the specified reader into the writer.
static String	read(File in) Reads the contents of a file into a string.
static String	read(InputStream in) Reads the contents of an input stream into a string using the system default charset.
static String	read(InputStream in, Charset cs) Reads the contents of an input stream into a string using the specified charset.
static String	read(Object o) Reads the specified object to a String.
static String	read(Reader in) Reads the contents of a reader into a string.
static String	read(Reader in, int length, int bufferSize) Reads the specified input into a String until the end of the input is reached.
static byte[]	readBytes(File f) Reads a raw stream of bytes from the specified file.
static byte[]	readBytes(InputStream in, int bufferSize) Read the specified input stream into a byte array and closes the stream.
static String	readFile(String path) Reads the contents of a file into a string.
static InputStream	toInputStream(Object o) Converts an object to an InputStream.
static Reader	toReader(Object o) Converts an object to a Reader.
static int	write(File out, InputStream in) Writes the contents of the specified InputStream to the specified file.
static int	write(File out, Reader in) Writes the contents of the specified Reader to the specified file.

Methods inherited from class java.lang.Object

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

Field Detail

UTF8

public static final Charset UTF8

UTF-8 charset

Constructor Detail

IOUtils

public IOUtils()

Method Detail

readFile

public static String readFile(String path)
                       throws IOException

Reads the contents of a file into a string.

Parameters:

path - The path of the file to read using default character encoding.

Returns:

The contents of the reader as a string, or null if file does not exist.

Throws:

IOException - If a problem occurred trying to read from the reader.

read

public static String read(File in)
                   throws IOException

Reads the contents of a file into a string.

Parameters:

in - The file to read using default character encoding.

Returns:

The contents of the reader as a string, or null if file does not exist.

Throws:

IOException - If a problem occurred trying to read from the reader.

read

public static String read(Object o)
                   throws IOException

Reads the specified object to a String.

Can be any of the following object types:

• CharSequence
• File
• Reader
• InputStream
• byte[]

Parameters:

o - The object to read.

Returns:

The object serialized to a string, or null if it wasn't a supported type.

Throws:

IOException

write

public static int write(File out,
                        Reader in)
                 throws IOException

Writes the contents of the specified Reader to the specified file.

Parameters:

out - The file to write the output to.

in - The reader to pipe from.

Returns:

The number of characters written to the file.

Throws:

IOException

write

public static int write(File out,
                        InputStream in)
                 throws IOException

Writes the contents of the specified InputStream to the specified file.

Parameters:

out - The file to write the output to.

in - The input stream to pipe from.

Returns:

The number of characters written to the file.

Throws:

IOException

read

public static String read(Reader in)
                   throws IOException

Reads the contents of a reader into a string.

Parameters:

in - The input reader.

Returns:

The contents of the reader as a string.

Throws:

IOException - If a problem occurred trying to read from the reader.

read

public static String read(InputStream in,
                          Charset cs)
                   throws IOException

Reads the contents of an input stream into a string using the specified charset.

Parameters:

in - The input stream.

cs - The charset of the contents of the input stream.

Returns:

The contents of the reader as a string. null if input stream was null.

Throws:

IOException - If a problem occurred trying to read from the input stream.

read

public static String read(InputStream in)
                   throws IOException

Reads the contents of an input stream into a string using the system default charset.

Parameters:

in - The input stream.

Returns:

The contents of the reader as a string, or null if the input stream is null.

Throws:

IOException - If a problem occurred trying to read from the input stream.

readBytes

public static byte[] readBytes(InputStream in,
                               int bufferSize)
                        throws IOException

Read the specified input stream into a byte array and closes the stream.

Parameters:

in - The input stream.

bufferSize - The expected size of the buffer.

Returns:

The contents of the stream as a byte array.

Throws:

IOException - Thrown by underlying stream.

readBytes

public static byte[] readBytes(File f)
                        throws IOException

Reads a raw stream of bytes from the specified file.

Parameters:

f - The file to read.

Returns:

A byte array containing the contents of the file.

Throws:

IOException

read

public static String read(Reader in,
                          int length,
                          int bufferSize)
                   throws IOException

Reads the specified input into a String until the end of the input is reached.

The Reader is automatically closed.

If the Reader is not an instance of a BufferedReader, then it gets wrapped in a BufferedReader.

Parameters:

in - The input reader.

length - Specify a positive number if the length of the input is known.

bufferSize - Specify the buffer size to use.

Returns:

The contents of the reader as a string. null if reader was null.

Throws:

IOException - If a problem occurred trying to read from the reader.

pipe

public static void pipe(Reader in,
                        Writer out)
                 throws IOException

Pipes the contents of the specified reader into the writer.

The reader is closed, the writer is not.

Parameters:

in - The reader to pipe from.

out - The writer to pipe to.

Throws:

IOException

pipe

public static void pipe(Object in,
                        Writer out)
                 throws IOException

Pipes the contents of the specified object into the writer.

The reader is closed, the writer is not.

Parameters:

in - The input to pipe from. Can be any of the types defined by toReader(Object).

out - The writer to pipe to.

Throws:

IOException

pipe

public static void pipe(InputStream in,
                        OutputStream out)
                 throws IOException

Pipes the contents of the specified streams.

The input stream is closed, the output stream is not.

Parameters:

in - The reader to pipe from.

out - The writer to pipe to.

Throws:

IOException

pipe

public static void pipe(Object in,
                        OutputStream out)
                 throws IOException

Pipes the contents of the specified object into the output stream.

The input stream is closed, the output stream is not.

Parameters:

in - The input to pipe from. Can be any of the types defined by toInputStream(Object).

out - The writer to pipe to.

Throws:

IOException

getBufferedReader

public static Reader getBufferedReader(Reader r)

Wraps the specified reader in a buffered reader.

Parameters:

r - The reader being wrapped.

Returns:

The reader wrapped in a BufferedReader, or the original Reader if it's already a buffered reader.

count

public static long count(InputStream is)
                  throws IOException

Counts the number of bytes in the input stream and then closes the stream.

Parameters:

is - The input stream to read from.

Returns:

The number of bytes read.

Throws:

IOException

count

public static long count(Reader r)
                  throws IOException

Counts the number of characters in the reader and then closes the reader.

Parameters:

r - The reader to read from.

Returns:

The number of characters read.

Throws:

IOException

getBufferSize

public static int getBufferSize(String contentLength)

Given the specified "Content-Length" header value, return an appropriate buffer size.

The maximum buffer size is 1MB.

Parameters:

contentLength - The value of the "Content-Length" header.

Returns:

The appropriate buffer size.

closeQuietly

public static void closeQuietly(InputStream is)

Close input stream and ignore any exceptions.

No-op if input stream is null.

Parameters:

is - The input stream to close.

closeQuietly

public static void closeQuietly(OutputStream os)

Close output stream and ignore any exceptions.

No-op if output stream is null.

Parameters:

os - The output stream to close.

closeQuietly

public static void closeQuietly(Reader r)

Close reader and ignore any exceptions.

No-op if reader is null.

Parameters:

r - The reader to close.

closeQuietly

public static void closeQuietly(Writer w)

Close writer and ignore any exceptions.

No-op if writer is null.

Parameters:

w - The writer to close.

closeQuietly

public static void closeQuietly(Object... o)

Quietly close all specified input streams, output streams, readers, and writers.

Parameters:

o - The list of all objects to quietly close.

flush

public static void flush(Object... o)
                  throws IOException

Flushes multiple output streams and writers in a single call.

Parameters:

o - The objects to flush. null entries are ignored.

Throws:

IOException

close

public static void close(Object... o)
                  throws IOException

Close all specified input streams, output streams, readers, and writers.

Parameters:

o - The list of all objects to close. null entries are ignored.

Throws:

IOException

toReader

public static Reader toReader(Object o)
                       throws IOException

Converts an object to a Reader.

Parameters:

o - The object to convert to a reader. Can be any of the following:

• InputStream
• Reader
• File
• CharSequence
• byte[]
• null - Returns null.

Returns:

The object converted to a reader.

Throws:

IOException - If file could not be read.

IllegalArgumentException - If invalid object passed in.

toInputStream

public static InputStream toInputStream(Object o)
                                 throws IOException

Converts an object to an InputStream.

Parameters:

o - The object to convert to an input stream. Can be any of the following:

• InputStream
• Reader
• File
• CharSequence - Converted to UTF-8 stream.
• byte[]
• null - Returns null.

Returns:

The object converted to an input stream.

Throws:

IOException - If file could not be read.

IllegalArgumentException - If invalid object passed in.