org.apache.commons.io.output

Class ByteArrayOutputStream

java.lang.Object

java.io.OutputStream

org.apache.commons.io.output.ByteArrayOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class ByteArrayOutputStream
extends java.io.OutputStream

This class implements an output stream in which the data is written into a byte array. The buffer automatically grows as data is written to it.

The data can be retrieved using toByteArray() and toString().

Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

This is an alternative implementation of the java.io.ByteArrayOutputStream class. The original implementation only allocates 32 bytes at the beginning. As this class is designed for heavy duty it starts at 1024 bytes. In contrast to the original it doesn't reallocate the whole memory block but allocates additional buffers. This way no buffers need to be garbage collected and the contents don't have to be copied to the new buffer. This class is designed to behave exactly like the original. The only exception is the deprecated toString(int) method that has been ignored.

Version:

$Id: ByteArrayOutputStream.java 610010 2008-01-08 14:50:59Z niallp $

Author:

Jeremias Maerki, Holger Hoffstatte

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List	buffers The list of buffers, which grows and never reduces.
private int	count The total count of bytes written.
private byte[]	currentBuffer The current buffer.
private int	currentBufferIndex The index of the current buffer.
private static byte[]	EMPTY_BYTE_ARRAY A singleton empty byte array.
private int	filledBufferSum The total count of bytes in all the filled buffers.

Constructor Summary

Constructors

Constructor and Description
ByteArrayOutputStream() Creates a new byte array output stream.
ByteArrayOutputStream(int size) Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.

Method Summary

Modifier and Type	Method and Description
void	close() Closing a ByteArrayOutputStream has no effect.
private byte[]	getBuffer(int index) Return the appropriate byte[] buffer specified by index.
private void	needNewBuffer(int newcount) Makes a new buffer available either by allocating a new one or re-cycling an existing one.
void	reset()
int	size() Return the current size of the byte array.
byte[]	toByteArray() Gets the curent contents of this byte stream as a byte array.
java.lang.String	toString() Gets the curent contents of this byte stream as a string.
java.lang.String	toString(java.lang.String enc) Gets the curent contents of this byte stream as a string using the specified encoding.
void	write(byte[] b, int off, int len) Write the bytes to byte array.
int	write(java.io.InputStream in) Writes the entire contents of the specified input stream to this byte stream.
void	write(int b) Write a byte to byte array.
void	writeTo(java.io.OutputStream out) Writes the entire contents of this byte stream to the specified output stream.

Methods inherited from class java.io.OutputStream

flush, write

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_BYTE_ARRAY

private static final byte[] EMPTY_BYTE_ARRAY

A singleton empty byte array.

buffers

private java.util.List buffers

The list of buffers, which grows and never reduces.

currentBufferIndex

private int currentBufferIndex

The index of the current buffer.

filledBufferSum

private int filledBufferSum

The total count of bytes in all the filled buffers.

currentBuffer

private byte[] currentBuffer

The current buffer.

count

private int count

The total count of bytes written.

Constructor Detail

ByteArrayOutputStream

public ByteArrayOutputStream()

Creates a new byte array output stream. The buffer capacity is initially 1024 bytes, though its size increases if necessary.

ByteArrayOutputStream

public ByteArrayOutputStream(int size)

Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.

Parameters:

size - the initial size

Throws:

java.lang.IllegalArgumentException - if size is negative

Method Detail

getBuffer

private byte[] getBuffer(int index)

Return the appropriate byte[] buffer specified by index.

Parameters:

index - the index of the buffer required

Returns:

the buffer

needNewBuffer

private void needNewBuffer(int newcount)

Makes a new buffer available either by allocating a new one or re-cycling an existing one.

Parameters:

newcount - the size of the buffer if one is created

write

public void write(byte[] b,
                  int off,
                  int len)

Write the bytes to byte array.

Overrides:

write in class java.io.OutputStream

Parameters:

b - the bytes to write

off - The start offset

len - The number of bytes to write

write

public void write(int b)

Write a byte to byte array.

Specified by:

write in class java.io.OutputStream

Parameters:

b - the byte to write

write

public int write(java.io.InputStream in)
          throws java.io.IOException

Writes the entire contents of the specified input stream to this byte stream. Bytes from the input stream are read directly into the internal buffers of this streams.

Parameters:

in - the input stream to read from

Returns:

total number of bytes read from the input stream (and written to this stream)

Throws:

java.io.IOException - if an I/O error occurs while reading the input stream

Since:

Commons IO 1.4

size

public int size()

Return the current size of the byte array.

Returns:

the current size of the byte array

close

public void close()
           throws java.io.IOException

Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException - never (this method should not declare this exception but it has to now due to backwards compatability)

reset

public void reset()

See Also:

ByteArrayOutputStream.reset()

writeTo

public void writeTo(java.io.OutputStream out)
             throws java.io.IOException

Writes the entire contents of this byte stream to the specified output stream.

Parameters:

out - the output stream to write to

Throws:

java.io.IOException - if an I/O error occurs, such as if the stream is closed

See Also:

ByteArrayOutputStream.writeTo(OutputStream)

toByteArray

public byte[] toByteArray()

Gets the curent contents of this byte stream as a byte array. The result is independent of this stream.

Returns:

the current contents of this output stream, as a byte array

See Also:

ByteArrayOutputStream.toByteArray()

toString

public java.lang.String toString()

Gets the curent contents of this byte stream as a string.

Overrides:

toString in class java.lang.Object

Returns:

the contents of the byte array as a String

See Also:

ByteArrayOutputStream.toString()

toString

public java.lang.String toString(java.lang.String enc)
                          throws java.io.UnsupportedEncodingException

Gets the curent contents of this byte stream as a string using the specified encoding.

Parameters:

enc - the name of the character encoding

Returns:

the string converted from the byte array

Throws:

java.io.UnsupportedEncodingException - if the encoding is not supported

See Also:

ByteArrayOutputStream.toString(String)