org.apache.commons.io.output

Class ByteArrayOutputStream

public class ByteArrayOutputStream extends 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
Listbuffers
The list of buffers, which grows and never reduces.
intcount
The total count of bytes written.
byte[]currentBuffer
The current buffer.
intcurrentBufferIndex
The index of the current buffer.
static byte[]EMPTY_BYTE_ARRAY
A singleton empty byte array.
intfilledBufferSum
The total count of bytes in all the filled buffers.
Constructor Summary
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
voidclose()
Closing a ByteArrayOutputStream has no effect.
byte[]getBuffer(int index)
Return the appropriate byte[] buffer specified by index.
voidneedNewBuffer(int newcount)
Makes a new buffer available either by allocating a new one or re-cycling an existing one.
voidreset()
intsize()
Return the current size of the byte array.
byte[]toByteArray()
Gets the curent contents of this byte stream as a byte array.
StringtoString()
Gets the curent contents of this byte stream as a string.
StringtoString(String enc)
Gets the curent contents of this byte stream as a string using the specified encoding.
voidwrite(byte[] b, int off, int len)
Write the bytes to byte array.
voidwrite(int b)
Write a byte to byte array.
intwrite(InputStream in)
Writes the entire contents of the specified input stream to this byte stream.
voidwriteTo(OutputStream out)
Writes the entire contents of this byte stream to the specified output stream.

Field Detail

buffers

private List buffers
The list of buffers, which grows and never reduces.

count

private int count
The total count of bytes written.

currentBuffer

private byte[] currentBuffer
The current buffer.

currentBufferIndex

private int currentBufferIndex
The index of the current buffer.

EMPTY_BYTE_ARRAY

private static final byte[] EMPTY_BYTE_ARRAY
A singleton empty byte array.

filledBufferSum

private int filledBufferSum
The total count of bytes in all the filled buffers.

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: IllegalArgumentException if size is negative

Method Detail

close

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

Throws: IOException never (this method should not declare this exception but it has to now due to backwards compatability)

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

reset

public void reset()

See Also: java.io.ByteArrayOutputStream#reset()

size

public int size()
Return the current size of the byte array.

Returns: the current size of the byte array

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: java.io.ByteArrayOutputStream#toByteArray()

toString

public String toString()
Gets the curent contents of this byte stream as a string.

Returns: the contents of the byte array as a String

See Also: java.io.ByteArrayOutputStream#toString()

toString

public String toString(String enc)
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: UnsupportedEncodingException if the encoding is not supported

See Also: java.io.ByteArrayOutputStream#toString(String)

write

public void write(byte[] b, int off, int len)
Write the bytes to byte array.

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.

Parameters: b the byte to write

write

public int write(InputStream in)
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: IOException if an I/O error occurs while reading the input stream

Since: Commons IO 1.4

writeTo

public void writeTo(OutputStream out)
Writes the entire contents of this byte stream to the specified output stream.

Parameters: out the output stream to write to

Throws: IOException if an I/O error occurs, such as if the stream is closed

See Also: java.io.ByteArrayOutputStream#writeTo(OutputStream)

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