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 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.

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.
void	reset()
int	size() Return the current size of the byte array.
static java.io.InputStream	toBufferedInputStream(java.io.InputStream input) Fetches entire contents of an InputStream and represent same data as result InputStream.
static java.io.InputStream	toBufferedInputStream(java.io.InputStream input, int size) Fetches entire contents of an InputStream and represent same data as result InputStream.
byte[]	toByteArray() Gets the current contents of this byte stream as a byte array.
java.io.InputStream	toInputStream() Gets the current contents of this byte stream as a Input Stream.
java.lang.String	toString() Deprecated. 2.5 use toString(String) instead
java.lang.String	toString(java.nio.charset.Charset charset) Gets the current contents of this byte stream as a string using the specified encoding.
java.lang.String	toString(java.lang.String enc) Gets the current 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

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

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:

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 compatibility)

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)

toBufferedInputStream

public static java.io.InputStream toBufferedInputStream(java.io.InputStream input)
                                                 throws java.io.IOException

Fetches entire contents of an InputStream and represent same data as result InputStream.

This method is useful where,

• Source InputStream is slow.
• It has network resources associated, so we cannot keep it open for long time.
• It has network timeout associated.

It can be used in favor of toByteArray(), since it avoids unnecessary allocation and copy of byte[].
This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - Stream to be fully buffered.

Returns:

A fully buffered stream.

Throws:

java.io.IOException - if an I/O error occurs

Since:

2.0

toBufferedInputStream

public static java.io.InputStream toBufferedInputStream(java.io.InputStream input,
                                                        int size)
                                                 throws java.io.IOException

Fetches entire contents of an InputStream and represent same data as result InputStream.

This method is useful where,

• Source InputStream is slow.
• It has network resources associated, so we cannot keep it open for long time.
• It has network timeout associated.

It can be used in favor of toByteArray(), since it avoids unnecessary allocation and copy of byte[].
This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - Stream to be fully buffered.

size - the initial buffer size

Returns:

A fully buffered stream.

Throws:

java.io.IOException - if an I/O error occurs

Since:

2.5

toInputStream

public java.io.InputStream toInputStream()

Gets the current contents of this byte stream as a Input Stream. The returned stream is backed by buffers of this stream, avoiding memory allocation and copy, thus saving space and time.

Returns:

the current contents of this output stream.

Since:

2.5

See Also:

ByteArrayOutputStream.toByteArray(), reset()

toByteArray

public byte[] toByteArray()

Gets the current 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

@Deprecated
public java.lang.String toString()

Deprecated. 2.5 use toString(String) instead

Gets the current contents of this byte stream as a string using the platform default charset.

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 current 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)

toString

public java.lang.String toString(java.nio.charset.Charset charset)

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

Parameters:

charset - the character encoding

Returns:

the string converted from the byte array

Since:

2.5

See Also:

ByteArrayOutputStream.toString(String)