public abstract class ByteString implements Iterable<Byte>, Serializable
Immutable sequence of bytes. Provides conversions to and from byte[]
, java.lang.String, ByteBuffer, InputStream, OutputStream. Also provides a
conversion to CodedInputStream.
Like String, the contents of a ByteString can never be observed to change, not even in the presence of a data race or incorrect API usage in the client code.
Substring is supported by sharing the reference to the immutable underlying bytes. Concatenation is likewise supported without copying (long strings) by building a tree of pieces in RopeByteString.
Static Fields
EMPTY
public static final ByteString EMPTY
Empty ByteString
.
Field Value | |
---|---|
Type | Description |
ByteString |
Static Methods
copyFrom(byte[] bytes)
public static ByteString copyFrom(byte[] bytes)
Copies the given bytes into a ByteString
.
Parameter | |
---|---|
Name | Description |
bytes | byte[] to copy |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFrom(byte[] bytes, int offset, int size)
public static ByteString copyFrom(byte[] bytes, int offset, int size)
Copies the given bytes into a ByteString
.
Parameters | |
---|---|
Name | Description |
bytes | byte[] source array |
offset | int offset in source array |
size | int number of bytes to copy |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFrom(Iterable<ByteString> byteStrings)
public static ByteString copyFrom(Iterable<ByteString> byteStrings)
Concatenates all byte strings in the iterable and returns the result. This is designed to run in O(list size), not O(total bytes).
The returned ByteString
is not necessarily a unique object. If the list is empty,
the returned object is the singleton empty ByteString
. If the list has only one
element, that ByteString
will be returned without copying.
Parameter | |
---|---|
Name | Description |
byteStrings | Iterable<ByteString> strings to be concatenated |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFrom(String text, String charsetName)
public static ByteString copyFrom(String text, String charsetName)
Encodes text
into a sequence of bytes using the named charset and returns the result as
a ByteString
.
Parameters | |
---|---|
Name | Description |
text | String source string |
charsetName | String encoding to use |
Returns | |
---|---|
Type | Description |
ByteString | new |
Exceptions | |
---|---|
Type | Description |
UnsupportedEncodingException | if the encoding isn't found |
copyFrom(String text, Charset charset)
public static ByteString copyFrom(String text, Charset charset)
Encodes text
into a sequence of bytes using the named charset and returns the result as
a ByteString
.
Parameters | |
---|---|
Name | Description |
text | String source string |
charset | Charset encode using this charset |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFrom(ByteBuffer bytes)
public static ByteString copyFrom(ByteBuffer bytes)
Copies the remaining bytes from a java.nio.ByteBuffer
into a ByteString
.
Parameter | |
---|---|
Name | Description |
bytes | ByteBuffer sourceBuffer |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFrom(ByteBuffer bytes, int size)
public static ByteString copyFrom(ByteBuffer bytes, int size)
Copies the next size
bytes from a java.nio.ByteBuffer
into a
ByteString
.
Parameters | |
---|---|
Name | Description |
bytes | ByteBuffer source buffer |
size | int number of bytes to copy |
Returns | |
---|---|
Type | Description |
ByteString | new |
copyFromUtf8(String text)
public static ByteString copyFromUtf8(String text)
Encodes text
into a sequence of UTF-8 bytes and returns the result as a
ByteString
.
Parameter | |
---|---|
Name | Description |
text | String source string |
Returns | |
---|---|
Type | Description |
ByteString | new |
newOutput()
public static ByteString.Output newOutput()
Creates a new Output. Call Output#toByteString() to create the
ByteString
instance.
A ByteString.Output offers the same functionality as a ByteArrayOutputStream, except that it returns a ByteString rather than a byte
array
.
Returns | |
---|---|
Type | Description |
ByteString.Output |
|
newOutput(int initialCapacity)
public static ByteString.Output newOutput(int initialCapacity)
Creates a new Output with the given initial capacity. Call Output#toByteString() to create the ByteString
instance.
A ByteString.Output offers the same functionality as a ByteArrayOutputStream, except that it returns a ByteString rather than a byte
array.
Parameter | |
---|---|
Name | Description |
initialCapacity | int estimate of number of bytes to be written |
Returns | |
---|---|
Type | Description |
ByteString.Output |
|
readFrom(InputStream streamToDrain)
public static ByteString readFrom(InputStream streamToDrain)
Completely reads the given stream's bytes into a ByteString
, blocking if necessary
until all bytes are read through to the end of the stream.
Performance notes: The returned ByteString
is an immutable tree of byte
arrays ("chunks") of the stream data. The first chunk is small, with subsequent chunks each
being double the size, up to 8K.
Each byte read from the input stream will be copied twice to ensure that the resulting ByteString is truly immutable.
Parameter | |
---|---|
Name | Description |
streamToDrain | InputStream The source stream, which is read completely but not closed. |
Returns | |
---|---|
Type | Description |
ByteString | A new |
Exceptions | |
---|---|
Type | Description |
IOException | if there is a problem reading the underlying stream |
readFrom(InputStream streamToDrain, int chunkSize)
public static ByteString readFrom(InputStream streamToDrain, int chunkSize)
Completely reads the given stream's bytes into a ByteString
, blocking if necessary
until all bytes are read through to the end of the stream.
Performance notes: The returned ByteString
is an immutable tree of byte
arrays ("chunks") of the stream data. The chunkSize parameter sets the size of these byte
arrays.
Each byte read from the input stream will be copied twice to ensure that the resulting ByteString is truly immutable.
Parameters | |
---|---|
Name | Description |
streamToDrain | InputStream The source stream, which is read completely but not closed. |
chunkSize | int The size of the chunks in which to read the stream. |
Returns | |
---|---|
Type | Description |
ByteString | A new |
Exceptions | |
---|---|
Type | Description |
IOException | if there is a problem reading the underlying stream |
readFrom(InputStream streamToDrain, int minChunkSize, int maxChunkSize)
public static ByteString readFrom(InputStream streamToDrain, int minChunkSize, int maxChunkSize)
Helper method that takes the chunk size range as a parameter.
Parameters | |
---|---|
Name | Description |
streamToDrain | InputStream the source stream, which is read completely but not closed |
minChunkSize | int the minimum size of the chunks in which to read the stream |
maxChunkSize | int the maximum size of the chunks in which to read the stream |
Returns | |
---|---|
Type | Description |
ByteString | a new |
Exceptions | |
---|---|
Type | Description |
IOException | if there is a problem reading the underlying stream |
unsignedLexicographicalComparator()
public static Comparator<ByteString> unsignedLexicographicalComparator()
Returns a Comparator which compares ByteString-s lexicographically as sequences of unsigned bytes (i.e. values between 0 and 255, inclusive).
For example, (byte) -1
is considered to be greater than (byte) 1
because it
is interpreted as an unsigned value, 255
:
-1
-> 0b11111111 (two's complement) -> 2551
-> 0b00000001 -> 1
Returns | |
---|---|
Type | Description |
Comparator<ByteString> |
Methods
asReadOnlyByteBuffer()
public abstract ByteBuffer asReadOnlyByteBuffer()
Constructs a read-only java.nio.ByteBuffer
whose content is equal to the contents of
this byte string. The result uses the same backing array as the byte string, if possible.
Returns | |
---|---|
Type | Description |
ByteBuffer | wrapped bytes |
asReadOnlyByteBufferList()
public abstract List<ByteBuffer> asReadOnlyByteBufferList()
Constructs a list of read-only java.nio.ByteBuffer
objects such that the concatenation
of their contents is equal to the contents of this byte string. The result uses the same
backing arrays as the byte string.
By returning a list, implementations of this method may be able to avoid copying even when there are multiple backing arrays.
Returns | |
---|---|
Type | Description |
List<ByteBuffer> | a list of wrapped bytes |
byteAt(int index)
public abstract byte byteAt(int index)
Gets the byte at the given index. This method should be used only for random access to individual bytes. To access bytes sequentially, use the ByteIterator returned by #iterator(), and call #substring(int, int) first if necessary.
Parameter | |
---|---|
Name | Description |
index | int index of byte |
Returns | |
---|---|
Type | Description |
byte | the value |
concat(ByteString other)
public final ByteString concat(ByteString other)
Concatenate the given ByteString
to this one. Short concatenations, of total size
smaller than ByteString#CONCATENATE_BY_COPY_SIZE, are produced by copying the
underlying bytes (as per Rope.java,
BAP95 . In general, the concatenate involves no copying.
Parameter | |
---|---|
Name | Description |
other | ByteString string to concatenate |
Returns | |
---|---|
Type | Description |
ByteString | a new |
copyTo(byte[] target, int offset)
public void copyTo(byte[] target, int offset)
Copies bytes into a buffer at the given offset.
To copy a subset of bytes, you call this method on the return value of #substring(int, int). Example: byteString.substring(start, end).copyTo(target, offset)
Parameters | |
---|---|
Name | Description |
target | byte[] buffer to copy into |
offset | int in the target buffer |
copyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy) (deprecated)
public final void copyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)
Deprecated. Instead, call byteString.substring(sourceOffset, sourceOffset +
numberToCopy).copyTo(target, targetOffset)
Copies bytes into a buffer.
Parameters | |
---|---|
Name | Description |
target | byte[] buffer to copy into |
sourceOffset | int offset within these bytes |
targetOffset | int offset within the target buffer |
numberToCopy | int number of bytes to copy |
copyTo(ByteBuffer target)
public abstract void copyTo(ByteBuffer target)
Copies bytes into a ByteBuffer.
To copy a subset of bytes, you call this method on the return value of #substring(int, int). Example: byteString.substring(start, end).copyTo(target)
Parameter | |
---|---|
Name | Description |
target | ByteBuffer ByteBuffer to copy into. |
copyToInternal(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)
protected abstract void copyToInternal(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)
Internal (package private) implementation of #copyTo(byte[],int,int,int). It assumes
that all error checking has already been performed and that numberToCopy > 0
.
Parameters | |
---|---|
Name | Description |
target | byte[] |
sourceOffset | int |
targetOffset | int |
numberToCopy | int |
endsWith(ByteString suffix)
public final boolean endsWith(ByteString suffix)
Tests if this bytestring ends with the specified suffix. Similar to String#endsWith(String)
Parameter | |
---|---|
Name | Description |
suffix | ByteString the suffix. |
Returns | |
---|---|
Type | Description |
boolean |
|
equals(Object o)
public abstract boolean equals(Object o)
Parameter | |
---|---|
Name | Description |
o | Object |
Returns | |
---|---|
Type | Description |
boolean |
getTreeDepth()
protected abstract int getTreeDepth()
Return the depth of the tree representing this ByteString
, if any, whose root is this
node. If this is a leaf node, return 0.
Returns | |
---|---|
Type | Description |
int | tree depth or zero |
hashCode()
public final int hashCode()
Compute the hashCode using the traditional algorithm from ByteString.
Returns | |
---|---|
Type | Description |
int | hashCode value |
isBalanced()
protected abstract boolean isBalanced()
Return true
if this ByteString is literal (a leaf node) or a flat-enough tree in the
sense of RopeByteString.
Returns | |
---|---|
Type | Description |
boolean | true if the tree is flat enough |
isEmpty()
public final boolean isEmpty()
Returns true
if the size is 0
, false
otherwise.
Returns | |
---|---|
Type | Description |
boolean | true if this is zero bytes long |
isValidUtf8()
public abstract boolean isValidUtf8()
Tells whether this ByteString
represents a well-formed UTF-8 byte sequence, such that
the original bytes can be converted to a String object and then round tripped back to bytes
without loss.
More precisely, returns true
whenever:
Arrays.equals(byteString.toByteArray(),
new String(byteString.toByteArray(), "UTF-8").getBytes("UTF-8"))
This method returns false
for "overlong" byte sequences, as well as for 3-byte
sequences that would map to a surrogate character, in accordance with the restricted definition
of UTF-8 introduced in Unicode 3.1. Note that the UTF-8 decoder included in Oracle's JDK has
been modified to also reject "overlong" byte sequences, but (as of 2011) still accepts 3-byte
surrogate character byte sequences.
See the Unicode Standard,
Table 3-6. UTF-8 Bit Distribution,
Table 3-7. Well Formed UTF-8 Byte Sequences.
Returns | |
---|---|
Type | Description |
boolean | whether the bytes in this |
iterator()
public ByteString.ByteIterator iterator()
Return a ByteString.ByteIterator over the bytes in the ByteString. To avoid auto-boxing, you may get the iterator manually and call ByteIterator#nextByte().
Returns | |
---|---|
Type | Description |
ByteString.ByteIterator | the iterator |
newCodedInput()
public abstract CodedInputStream newCodedInput()
Creates a CodedInputStream which can be used to read the bytes. Using this is often more efficient than creating a CodedInputStream that wraps the result of #newInput().
Returns | |
---|---|
Type | Description |
CodedInputStream | stream based on wrapped data |
newInput()
public abstract InputStream newInput()
Creates an InputStream
which can be used to read the bytes.
The InputStream returned by this method is guaranteed to be completely non-blocking.
The method InputStream#available() returns the number of bytes remaining in the stream.
The methods InputStream#read(byte[]), InputStream#read(byte[],int,int) and
InputStream#skip(long) will read/skip as many bytes as are available. The method InputStream#markSupported() returns true
.
The methods in the returned InputStream might not be thread safe.
Returns | |
---|---|
Type | Description |
InputStream | an input stream that returns the bytes of this byte string. |
partialHash(int h, int offset, int length)
protected abstract int partialHash(int h, int offset, int length)
Compute the hash across the value bytes starting with the given hash, and return the result. This is used to compute the hash across strings represented as a set of pieces by allowing the hash computation to be continued from piece to piece.
Parameters | |
---|---|
Name | Description |
h | int starting hash value |
offset | int offset into this value to start looking at data values |
length | int number of data values to include in the hash computation |
Returns | |
---|---|
Type | Description |
int | ending hash value |
partialIsValidUtf8(int state, int offset, int length)
protected abstract int partialIsValidUtf8(int state, int offset, int length)
Tells whether the given byte sequence is a well-formed, malformed, or incomplete UTF-8 byte
sequence. This method accepts and returns a partial state result, allowing the bytes for a
complete UTF-8 byte sequence to be composed from multiple ByteString
segments.
Parameters | |
---|---|
Name | Description |
state | int either |
offset | int offset of the first byte to check |
length | int number of bytes to check |
Returns | |
---|---|
Type | Description |
int |
|
peekCachedHashCode()
protected final int peekCachedHashCode()
Return the cached hash code if available.
Returns | |
---|---|
Type | Description |
int | value of cached hash code or 0 if not computed yet |
size()
public abstract int size()
Gets the number of bytes.
Returns | |
---|---|
Type | Description |
int | size in bytes |
startsWith(ByteString prefix)
public final boolean startsWith(ByteString prefix)
Tests if this bytestring starts with the specified prefix. Similar to String#startsWith(String)
Parameter | |
---|---|
Name | Description |
prefix | ByteString the prefix. |
Returns | |
---|---|
Type | Description |
boolean |
|
substring(int beginIndex)
public final ByteString substring(int beginIndex)
Return the substring from beginIndex
, inclusive, to the end of the string.
Parameter | |
---|---|
Name | Description |
beginIndex | int start at this index |
Returns | |
---|---|
Type | Description |
ByteString | substring sharing underlying data |
substring(int beginIndex, int endIndex)
public abstract ByteString substring(int beginIndex, int endIndex)
Return the substring from beginIndex
, inclusive, to endIndex
, exclusive.
Parameters | |
---|---|
Name | Description |
beginIndex | int start at this index |
endIndex | int the last character is the one before this index |
Returns | |
---|---|
Type | Description |
ByteString | substring sharing underlying data |
toByteArray()
public final byte[] toByteArray()
Copies bytes to a byte[]
.
Returns | |
---|---|
Type | Description |
byte[] | copied bytes |
toString()
public final String toString()
Returns | |
---|---|
Type | Description |
String |
toString(String charsetName)
public final String toString(String charsetName)
Constructs a new String
by decoding the bytes using the specified charset.
Parameter | |
---|---|
Name | Description |
charsetName | String encode using this charset |
Returns | |
---|---|
Type | Description |
String | new string |
Exceptions | |
---|---|
Type | Description |
UnsupportedEncodingException | if charset isn't recognized |
toString(Charset charset)
public final String toString(Charset charset)
Constructs a new String
by decoding the bytes using the specified charset. Returns the
same empty String if empty.
Parameter | |
---|---|
Name | Description |
charset | Charset encode using this charset |
Returns | |
---|---|
Type | Description |
String | new string |
toStringInternal(Charset charset)
protected abstract String toStringInternal(Charset charset)
Constructs a new String
by decoding the bytes using the specified charset.
Parameter | |
---|---|
Name | Description |
charset | Charset encode using this charset |
Returns | |
---|---|
Type | Description |
String | new string |
toStringUtf8()
public final String toStringUtf8()
Constructs a new String
by decoding the bytes as UTF-8.
Returns | |
---|---|
Type | Description |
String | new string using UTF-8 encoding |
writeTo(OutputStream out)
public abstract void writeTo(OutputStream out)
Writes a copy of the contents of this byte string to the specified output stream argument.
Parameter | |
---|---|
Name | Description |
out | OutputStream the output stream to which to write the data. |
Exceptions | |
---|---|
Type | Description |
IOException | if an I/O error occurs. |