Class ByteChunk

java.lang.Object

org.apache.tomcat.util.buf.AbstractChunk

org.apache.tomcat.util.buf.ByteChunk

All Implemented Interfaces:

Serializable, Cloneable

public final class ByteChunk
extends AbstractChunk

This class is used to represent a chunk of bytes, and utilities to manipulate byte[].

The buffer can be modified and used for both input and output.

There are 2 modes: The chunk can be associated with a sink - ByteInputChannel or ByteOutputChannel, which will be used when the buffer is empty (on input) or filled (on output). For output, it can also grow. This operating mode is selected by calling setLimit() or allocate(initial, limit) with limit != -1.

Various search and append method are defined - similar with String and StringBuffer, but operating on bytes.

This is important because it allows processing the http headers directly on the received bytes, without converting to chars and Strings until the strings are needed. In addition, the charset is determined later, from headers or user code.

In a server it is very important to be able to operate on the original byte[] without converting everything to chars. Some protocols are ASCII only, and some allow different non-UNICODE encodings. The encoding is not known beforehand, and can even change during the execution of the protocol. ( for example a multipart message may have parts with different encoding )

For HTTP, it is not very clear how the encoding of RequestURI and mime values can be determined, but it is a great advantage to be able to parse the request without converting to string.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ByteChunk.BufferOverflowException	Exception thrown when a byte chunk buffer overflows.
static interface	ByteChunk.ByteInputChannel	Input interface, used when the buffer is empty.
static interface	ByteChunk.ByteOutputChannel	When we need more space we'll either grow the buffer ( up to the limit ) or send it to a channel.

Field Summary

Fields

Modifier and Type	Field	Description
static final Charset	DEFAULT_CHARSET	Default encoding used to convert to strings.

Fields inherited from class AbstractChunk

ARRAY_MAX_SIZE, end, hasHashCode, isSet, sm, start

Constructor Summary

Constructors

Constructor	Description
ByteChunk()	Creates a new, uninitialized ByteChunk object.
ByteChunk(int initial)	Creates a ByteChunk with the specified initial buffer size.

Method Summary

Modifier and Type	Method	Description
void	allocate(int initial, int limit)	Allocates a buffer with the specified initial size and optional limit.
void	append(byte b)	Appends a single byte to this chunk.
void	append(byte[] src, int off, int len)	Add data to the buffer.
void	append(ByteBuffer from)	Add data to the buffer.
void	append(ByteChunk src)	Appends the contents of another ByteChunk.
ByteChunk	clone()
static byte[]	convertToBytes(String value)	Convert specified String to a byte array.
boolean	equals(byte[] b2, int off2, int len2)	Compares this chunk to a byte array region.
boolean	equals(char[] c2, int off2, int len2)	Compares the message bytes to the specified char array.
boolean	equals(Object obj)
boolean	equals(String s)	Compares the message bytes to the specified String object.
boolean	equals(ByteChunk bb)	Compares this chunk to another ByteChunk.
boolean	equals(CharChunk cc)	Compares this chunk to a CharChunk.
boolean	equalsIgnoreCase(byte[] b2, int off2, int len2)	Compares this chunk to a byte array region, ignoring case.
boolean	equalsIgnoreCase(String s)	Compares the message bytes to the specified String object.
static int	findByte(byte[] bytes, int start, int end, byte b)	Returns the first instance of the given byte in the byte array between the specified start and end.
static int	findBytes(byte[] bytes, int start, int end, byte[] b)	Returns the first instance of the given bytes in the byte array between the specified start and end.
void	flushBuffer()	Send the buffer to the sink.
byte[]	getBuffer()	Returns the underlying byte array.
protected int	getBufferElement(int index)	Returns the element at the specified index in the buffer.
byte[]	getBytes()	Returns the underlying byte array.
Charset	getCharset()	Returns the character set for this chunk.
long	getLong()	Parses the byte chunk content as a long integer.
static int	indexOf(byte[] bytes, int start, int end, char s)	Returns the first instance of the given character in the given byte array between the specified start and end.
int	indexOf(char c, int starting)	Returns the first instance of the given character in this ByteChunk starting at the specified byte.
void	makeSpace(int count)	Make space for len bytes.
void	recycle()	Resets the chunk to an uninitialized state.
void	setByteInputChannel(ByteChunk.ByteInputChannel in)	When the buffer is empty, read the data from the input channel.
void	setByteOutputChannel(ByteChunk.ByteOutputChannel out)	When the buffer is full, write the data to the output channel.
void	setBytes(byte[] b, int off, int len)	Sets the buffer to the specified sub array of bytes.
void	setCharset(Charset charset)	Sets the character set for this chunk.
boolean	startsWith(String s, int pos)	Returns true if the buffer starts with the specified string when tested in a case-sensitive manner.
boolean	startsWithIgnoreCase(String s, int pos)	Returns true if the buffer starts with the specified string when tested in a case-insensitive manner.
int	subtract()	Reads and removes the next byte from this chunk.
int	subtract(byte[] dest, int off, int len)	Reads bytes into the specified array.
int	subtract(ByteBuffer to)	Transfers bytes from the buffer to the specified ByteBuffer.
byte	subtractB()	Deprecated. Use subtract() instead.
String	toString()
String	toString(CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction)	Converts the byte chunk to a String using the configured charset.
String	toStringInternal()	Deprecated. Unused.
String	toStringInternal(CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction)	Converts the current content of the byte buffer to a String using the configured character set.

Methods inherited from class AbstractChunk

getEnd, getLength, getLimit, getLimitInternal, getOffset, getStart, hash, hashCode, indexOf, isNull, setEnd, setLimit, setOffset, setStart

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

DEFAULT_CHARSET

public static final Charset DEFAULT_CHARSET

Default encoding used to convert to strings. It should be UTF8, as most standards seem to converge, but the servlet API requires 8859_1, and this object is used mostly for servlets.

Constructor Details

ByteChunk

public ByteChunk()

Creates a new, uninitialized ByteChunk object.

ByteChunk

public ByteChunk(int initial)

Creates a ByteChunk with the specified initial buffer size.

Parameters:

initial - initial buffer size

Method Details

clone

public ByteChunk clone()
                throws CloneNotSupportedException

Overrides:

clone in class Object

Throws:

CloneNotSupportedException

recycle

public void recycle()

Description copied from class: AbstractChunk

Resets the chunk to an uninitialized state.

Overrides:

recycle in class AbstractChunk

allocate

public void allocate(int initial,
 int limit)

Allocates a buffer with the specified initial size and optional limit.

Parameters:

initial - initial size

limit - maximum size or -1 for unlimited

setBytes

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

Sets the buffer to the specified sub array of bytes.

Parameters:

b - the ascii bytes

off - the start offset of the bytes

len - the length of the bytes

setCharset

public void setCharset(Charset charset)

Sets the character set for this chunk.

Parameters:

charset - the character set

getCharset

public Charset getCharset()

Returns the character set for this chunk.

Returns:

the character set

getBytes

public byte[] getBytes()

Returns the underlying byte array.

Returns:

the buffer

getBuffer

public byte[] getBuffer()

Returns the underlying byte array.

Returns:

the buffer

setByteInputChannel

public void setByteInputChannel(ByteChunk.ByteInputChannel in)

When the buffer is empty, read the data from the input channel.

Parameters:

in - The input channel

setByteOutputChannel

public void setByteOutputChannel(ByteChunk.ByteOutputChannel out)

When the buffer is full, write the data to the output channel. Also used when large amount of data is appended. If not set, the buffer will grow to the limit.

Parameters:

out - The output channel

append

public void append(byte b)
            throws IOException

Appends a single byte to this chunk.

Parameters:

b - the byte to append

Throws:

IOException - if writing fails

append

public void append(ByteChunk src)
            throws IOException

Appends the contents of another ByteChunk.

Parameters:

src - the source chunk

Throws:

IOException - if writing fails

append

public void append(byte[] src,
 int off,
 int len)
            throws IOException

Add data to the buffer.

Parameters:

src - Bytes array

off - Offset

len - Length

Throws:

IOException - Writing overflow data to the output channel failed

append

public void append(ByteBuffer from)
            throws IOException

Add data to the buffer.

Parameters:

from - the ByteBuffer with the data

Throws:

IOException - Writing overflow data to the output channel failed

subtract

public int subtract()
             throws IOException

Reads and removes the next byte from this chunk.

Returns:

the byte value (0-255) or -1 if end of data

Throws:

IOException - if reading from input channel fails

subtractB

@Deprecated
public byte subtractB()
               throws IOException

Deprecated.

Use subtract() instead. This method cannot distinguish between EOF (-1) and the legitimate byte value 0xFF because it returns byte.

Reads and removes the next byte from this chunk.

Returns:

the byte value or -1 if end of data

Throws:

IOException - if reading from input channel fails

subtract

public int subtract(byte[] dest,
 int off,
 int len)
             throws IOException

Reads bytes into the specified array.

Parameters:

dest - destination array

off - offset

len - maximum length

Returns:

number of bytes read or -1 if end of data

Throws:

IOException - if reading from input channel fails

subtract

public int subtract(ByteBuffer to)
             throws IOException

Transfers bytes from the buffer to the specified ByteBuffer. After the operation the position of the ByteBuffer will be returned to the one before the operation, the limit will be the position incremented by the number of the transferred bytes.

Parameters:

to - the ByteBuffer into which bytes are to be written.

Returns:

an integer specifying the actual number of bytes read, or -1 if the end of the stream is reached

Throws:

IOException - if an input or output exception has occurred

flushBuffer

public void flushBuffer()
                 throws IOException

Send the buffer to the sink. Called by append() when the limit is reached. You can also call it explicitly to force the data to be written.

Throws:

IOException - Writing overflow data to the output channel failed

makeSpace

public void makeSpace(int count)

Make space for len bytes. If len is small, allocate a reserve space too. Never grow bigger than the limit or AbstractChunk.ARRAY_MAX_SIZE.

Parameters:

count - The size

toString

public String toString()

Overrides:

toString in class Object

toString

public String toString(CodingErrorAction malformedInputAction,
 CodingErrorAction unmappableCharacterAction)
                throws CharacterCodingException

Converts the byte chunk to a String using the configured charset.

Parameters:

malformedInputAction - action for malformed input

unmappableCharacterAction - action for unmappable characters

Returns:

the string representation

Throws:

CharacterCodingException - if conversion fails

toStringInternal

@Deprecated
public String toStringInternal()

Deprecated.

Unused. This method will be removed in Tomcat 11 onwards.

Converts the current content of the byte buffer to a String using the configured character set.

Returns:

The result of converting the bytes to a String

toStringInternal

public String toStringInternal(CodingErrorAction malformedInputAction,
 CodingErrorAction unmappableCharacterAction)
                        throws CharacterCodingException

Converts the current content of the byte buffer to a String using the configured character set.

Parameters:

malformedInputAction - Action to take if the input is malformed

unmappableCharacterAction - Action to take if a byte sequence can't be mapped to a character

Returns:

The result of converting the bytes to a String

Throws:

CharacterCodingException - If an error occurs during the conversion

getLong

public long getLong()

Parses the byte chunk content as a long integer.

Returns:

the parsed long value

equals

public boolean equals(Object obj)

Description copied from class: AbstractChunk

Sub-classes must provide an equals implementation that is consistent with AbstractChunk.hashCode().

Specified by:

equals in class AbstractChunk

equals

public boolean equals(String s)

Compares the message bytes to the specified String object.

NOTE: This only works for characters in the range 0-127.

Parameters:

s - the String to compare

Returns:

true if the comparison succeeded, false otherwise

equalsIgnoreCase

public boolean equalsIgnoreCase(String s)

Compares the message bytes to the specified String object.

NOTE: This only works for characters in the range 0-255.

Parameters:

s - the String to compare

Returns:

true if the comparison succeeded, false otherwise

equals

public boolean equals(ByteChunk bb)

Compares this chunk to another ByteChunk.

Parameters:

bb - the ByteChunk to compare

Returns:

true if equal

equals

public boolean equals(byte[] b2,
 int off2,
 int len2)

Compares this chunk to a byte array region.

Parameters:

b2 - the byte array

off2 - offset

len2 - length

Returns:

true if equal

equalsIgnoreCase

public boolean equalsIgnoreCase(byte[] b2,
 int off2,
 int len2)

Compares this chunk to a byte array region, ignoring case.

Parameters:

b2 - the byte array

off2 - offset

len2 - length

Returns:

true if equal

equals

public boolean equals(CharChunk cc)

Compares this chunk to a CharChunk.

Parameters:

cc - the CharChunk to compare

Returns:

true if equal

equals

public boolean equals(char[] c2,
 int off2,
 int len2)

Compares the message bytes to the specified char array.

NOTE: This only works for characters in the range 0-127.

Parameters:

c2 - the array to compare to

off2 - offset

len2 - length

Returns:

true if the comparison succeeded, false otherwise

startsWith

public boolean startsWith(String s,
 int pos)

Returns true if the buffer starts with the specified string when tested in a case-sensitive manner.

NOTE: This only works for characters in the range 0-127.

Parameters:

s - the string

pos - The position

Returns:

true if the start matches

startsWithIgnoreCase

public boolean startsWithIgnoreCase(String s,
 int pos)

Returns true if the buffer starts with the specified string when tested in a case-insensitive manner.

NOTE: This only works for characters in the range 0-255.

Parameters:

s - the string

pos - The position

Returns:

true if the start matches

getBufferElement

protected int getBufferElement(int index)

Description copied from class: AbstractChunk

Returns the element at the specified index in the buffer.

Specified by:

getBufferElement in class AbstractChunk

Parameters:

index - the element location in the buffer

Returns:

the element

indexOf

public int indexOf(char c,
 int starting)

Returns the first instance of the given character in this ByteChunk starting at the specified byte. If the character is not found, -1 is returned.

NOTE: This only works for characters in the range 0-127.

Parameters:

c - The character

starting - The start position

Returns:

The position of the first instance of the character or -1 if the character is not found.

indexOf

public static int indexOf(byte[] bytes,
 int start,
 int end,
 char s)

Returns the first instance of the given character in the given byte array between the specified start and end.

NOTE: This only works for characters in the range 0-127.

Parameters:

bytes - The array to search

start - The point to start searching from in the array

end - The point to stop searching in the array

s - The character to search for

Returns:

The position of the first instance of the character or -1 if the character is not found.

findByte

public static int findByte(byte[] bytes,
 int start,
 int end,
 byte b)

Returns the first instance of the given byte in the byte array between the specified start and end.

Parameters:

bytes - The byte array to search

start - The point to start searching from in the byte array

end - The point to stop searching in the byte array

b - The byte to search for

Returns:

The position of the first instance of the byte or -1 if the byte is not found.

findBytes

public static int findBytes(byte[] bytes,
 int start,
 int end,
 byte[] b)

Returns the first instance of the given bytes in the byte array between the specified start and end.

Parameters:

bytes - The byte array to search

start - The point to start searching from in the byte array

end - The point to stop searching in the byte array

b - The array of bytes to search for

Returns:

The position of the first instance of the byte or -1 if the byte is not found.

convertToBytes

public static byte[] convertToBytes(String value)

Convert specified String to a byte array. This ONLY WORKS for ascii, UTF chars will be truncated.

Parameters:

value - to convert to byte array

Returns:

the byte array value