Class FastByteArrayOutputStream

java.lang.Object

java.io.OutputStream

it.unimi.dsi.fastutil.io.MeasurableOutputStream

it.unimi.dsi.fastutil.io.FastByteArrayOutputStream

All Implemented Interfaces:

MeasurableStream, RepositionableStream, Closeable, DataOutput, Flushable, ObjectOutput, AutoCloseable

public class FastByteArrayOutputStream
extends MeasurableOutputStream
implements RepositionableStream, ObjectOutput

Simple, fast byte-array output stream that exposes the backing array.

ByteArrayOutputStream is nice, but to get its content you must generate each time a new object. This doesn't happen here.

This class will automatically enlarge the backing array, doubling its size whenever new space is needed. The reset() method will mark the content as empty, but will not decrease the capacity: use trim() for that purpose.

Author:

Sebastiano Vigna

Field Summary

Fields

Modifier and Type	Field	Description
byte[]	array	The array backing the output stream.
static final int	DEFAULT_INITIAL_CAPACITY	The array backing the output stream.
int	length	The number of valid bytes in array.

Constructor Summary

Constructors

Constructor	Description
FastByteArrayOutputStream()	Creates a new array output stream with an initial capacity of DEFAULT_INITIAL_CAPACITY bytes.
FastByteArrayOutputStream(byte[] a)	Creates a new array output stream wrapping a given byte array.
FastByteArrayOutputStream(int initialCapacity)	Creates a new array output stream with a given initial capacity.

Method Summary

Modifier and Type	Method	Description
void	close()
long	length()	Returns the overall length of this stream (optional operation).
long	position()	Returns the current position in this stream (optional operation).
void	position(long newPosition)	Sets the current stream position.
void	reset()	Marks this array output stream as empty.
byte[]	toByteArray()
String	toString(Charset charset)
void	trim()	Ensures that the length of the backing array is equal to length.
void	write(byte[] b)
void	write(byte[] b, int off, int len)
void	write(int b)
void	writeBoolean(boolean v)
void	writeByte(int v)
void	writeBytes(String s)	Deprecated. This method is dangerous as it discards the high byte of every character.
void	writeChar(int v)
void	writeChars(String s)
void	writeDouble(double v)
void	writeFloat(float v)
void	writeInt(int v)
void	writeLong(long v)
void	writeObject(Object obj)	not efficient!
void	writeShort(int v)
void	writeTo(OutputStream out)
void	writeUTF(String s)
int	writeUtf8Char(char c)

Methods inherited from class java.io.OutputStream

flush, nullOutputStream

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.io.ObjectOutput

flush

Field Details

DEFAULT_INITIAL_CAPACITY

public static final int DEFAULT_INITIAL_CAPACITY

The array backing the output stream.

See Also:

• Constant Field Values

array

public byte[] array

The array backing the output stream.

length

public int length

The number of valid bytes in array.

Constructor Details

FastByteArrayOutputStream

public FastByteArrayOutputStream()

Creates a new array output stream with an initial capacity of DEFAULT_INITIAL_CAPACITY bytes.

FastByteArrayOutputStream

public FastByteArrayOutputStream(int initialCapacity)

Creates a new array output stream with a given initial capacity.

Parameters:

initialCapacity - the initial length of the backing array.

FastByteArrayOutputStream

public FastByteArrayOutputStream(byte[] a)

Creates a new array output stream wrapping a given byte array.

Parameters:

a - the byte array to wrap.

Method Details

reset

public void reset()

Marks this array output stream as empty.

trim

public void trim()

Ensures that the length of the backing array is equal to length.

write

public void write(int b)

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Specified by:

write in class OutputStream

write

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

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Overrides:

write in class OutputStream

position

public void position(long newPosition)

Description copied from interface: RepositionableStream

Sets the current stream position.

Specified by:

position in interface RepositionableStream

Parameters:

newPosition - the new stream position.

position

public long position()

Description copied from interface: MeasurableStream

Returns the current position in this stream (optional operation).

Usually, the position is just the number of bytes read or written since the stream was opened, but in the case of a RepositionableStream it represent the current position.

Specified by:

position in interface MeasurableStream

Specified by:

position in interface RepositionableStream

Returns:

the current stream position.

length

public long length()

Description copied from interface: MeasurableStream

Returns the overall length of this stream (optional operation). In most cases, this will require the stream to perform some extra action, possibly changing the state of the input stream itself (typically, reading all the bytes up to the end, or flushing on output stream). Implementing classes should always document what state will the input stream be in after calling this method, and which kind of exception could be thrown.

Specified by:

length in interface MeasurableStream

toByteArray

public byte[] toByteArray()

See Also:

• ByteArrayOutputStream.toByteArray()

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface ObjectOutput

Overrides:

close in class OutputStream

write

public void write(byte[] b)

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Overrides:

write in class OutputStream

toString

public String toString(Charset charset)

See Also:

• ByteArrayOutputStream.toString(Charset)

writeTo

public void writeTo(OutputStream out)
             throws IOException

Throws:

IOException

See Also:

• ByteArrayOutputStream.writeTo(OutputStream)

writeBoolean

public void writeBoolean(boolean v)

Specified by:

writeBoolean in interface DataOutput

writeByte

public void writeByte(int v)

Specified by:

writeByte in interface DataOutput

writeShort

public void writeShort(int v)

Specified by:

writeShort in interface DataOutput

writeChar

public void writeChar(int v)

Specified by:

writeChar in interface DataOutput

writeInt

public void writeInt(int v)

Specified by:

writeInt in interface DataOutput

writeLong

public void writeLong(long v)

Specified by:

writeLong in interface DataOutput

writeFloat

public void writeFloat(float v)

Specified by:

writeFloat in interface DataOutput

writeDouble

public void writeDouble(double v)

Specified by:

writeDouble in interface DataOutput

writeBytes

@Deprecated
public void writeBytes(String s)

Deprecated.

This method is dangerous as it discards the high byte of every character. For UTF-8, use writeUTF(String) or @code write(s.getBytes(UTF_8)).

Specified by:

writeBytes in interface DataOutput

See Also:

• DataOutputStream.writeBytes(String)

writeChars

public void writeChars(String s)

Specified by:

writeChars in interface DataOutput

writeUTF

public void writeUTF(String s)

Specified by:

writeUTF in interface DataOutput

writeUtf8Char

public int writeUtf8Char(char c)

See Also:

• DataOutputStream.writeUTF(String,DataOutput)

writeObject

public void writeObject(Object obj)
                 throws IOException

not efficient! Only added to support custom Externalizable

Specified by:

writeObject in interface ObjectOutput

Throws:

IOException