ByteString

java.lang.Object
- com.google.protobuf.ByteString

All Implemented Interfaces:

Serializable, Iterable<Byte>
```
public abstract class ByteString
extends Object
implements Iterable<Byte>, Serializable
```
Immutable sequence of bytes. Substring is supported by sharing the reference to the immutable underlying bytes, as with String. Concatenation is likewise supported without copying (long strings) by building a tree of pieces in RopeByteString.
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.

Author:

crazybob@google.com Bob Lee, kenton@google.com Kenton Varda, carlanton@google.com Carl Haverl, martinrb@google.com Martin Buchholz

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`ByteString.ByteIterator` This interface extends `Iterator<Byte>`, so that we can return an unboxed `byte`.
`static class`	`ByteString.Output` Outputs to a `ByteString` instance.

Field Summary

Fields
Modifier and Type Field and Description

static ByteString EMPTY
Empty ByteString.

Fields
Modifier and Type	Field and Description
`static ByteString`	`EMPTY` Empty `ByteString`.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract ByteBuffer`	`asReadOnlyByteBuffer()` Constructs a read-only `java.nio.ByteBuffer` whose content is equal to the contents of this byte string.
`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.
`abstract byte`	`byteAt(int index)` Gets the byte at the given index.
`ByteString`	`concat(ByteString other)` Concatenate the given `ByteString` to this one.
`static ByteString`	`copyFrom(byte[] bytes)` Copies the given bytes into a `ByteString`.
`static ByteString`	`copyFrom(byte[] bytes, int offset, int size)` Copies the given bytes into a `ByteString`.
`static ByteString`	`copyFrom(ByteBuffer bytes)` Copies the remaining bytes from a `java.nio.ByteBuffer` into a `ByteString`.
`static ByteString`	`copyFrom(ByteBuffer bytes, int size)` Copies the next `size` bytes from a `java.nio.ByteBuffer` into a `ByteString`.
`static ByteString`	`copyFrom(Iterable<ByteString> byteStrings)` Concatenates all byte strings in the iterable and returns the result.
`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`.
`static ByteString`	`copyFromUtf8(String text)` Encodes `text` into a sequence of UTF-8 bytes and returns the result as a `ByteString`.
`void`	`copyTo(byte[] target, int offset)` Copies bytes into a buffer at the given offset.
`void`	`copyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)` Copies bytes into a buffer.
`abstract void`	`copyTo(ByteBuffer target)` Copies bytes into a ByteBuffer.
`protected abstract void`	`copyToInternal(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)` Internal (package private) implementation of `copyTo(byte[],int,int,int)`.
`boolean`	`endsWith(ByteString suffix)` Tests if this bytestring ends with the specified suffix.
`abstract boolean`	`equals(Object o)` Indicates whether some other object is "equal to" this one.
`protected abstract int`	`getTreeDepth()` Return the depth of the tree representing this `ByteString`, if any, whose root is this node.
`int`	`hashCode()` Compute the hashCode using the traditional algorithm from `ByteString`.
`protected abstract boolean`	`isBalanced()` Return `true` if this ByteString is literal (a leaf node) or a flat-enough tree in the sense of `RopeByteString`.
`boolean`	`isEmpty()` Returns `true` if the size is `0`, `false` otherwise.
`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.
`ByteString.ByteIterator`	`iterator()` Return a `ByteString.ByteIterator` over the bytes in the ByteString.
`abstract CodedInputStream`	`newCodedInput()` Creates a `CodedInputStream` which can be used to read the bytes.
`abstract InputStream`	`newInput()` Creates an `InputStream` which can be used to read the bytes.
`static ByteString.Output`	`newOutput()` Creates a new `ByteString.Output`.
`static ByteString.Output`	`newOutput(int initialCapacity)` Creates a new `ByteString.Output` with the given initial capacity.
`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.
`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.
`protected int`	`peekCachedHashCode()` Return the cached hash code if available.
`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.
`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.
`static ByteString`	`readFrom(InputStream streamToDrain, int minChunkSize, int maxChunkSize)`
`abstract int`	`size()` Gets the number of bytes.
`boolean`	`startsWith(ByteString prefix)` Tests if this bytestring starts with the specified prefix.
`ByteString`	`substring(int beginIndex)` Return the substring from `beginIndex`, inclusive, to the end of the string.
`abstract ByteString`	`substring(int beginIndex, int endIndex)` Return the substring from `beginIndex`, inclusive, to `endIndex`, exclusive.
`byte[]`	`toByteArray()` Copies bytes to a `byte[]`.
`String`	`toString()` Returns a string representation of the object.
`String`	`toString(String charset)` Constructs a new `String` by decoding the bytes using the specified charset.
`protected abstract String`	`toStringInternal(String charset)` Constructs a new `String` by decoding the bytes using the specified charset.
`String`	`toStringUtf8()` Constructs a new `String` by decoding the bytes as UTF-8.
`abstract void`	`writeTo(OutputStream out)` Writes a copy of the contents of this byte string to the specified output stream argument.

Methods inherited from class java.lang.Object
clone, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - EMPTY
```
public static final ByteString EMPTY
```
    Empty ByteString.
- Method Detail
  - 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:
    
    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:
    
    a list of wrapped bytes
  - byteAt
```
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 ByteString.ByteIterator returned by iterator(), and call substring(int, int) first if necessary.
    
    Parameters:
    
    index - index of byte
    
    Returns:
    
    the value
    
    Throws:
    
    IndexOutOfBoundsException - index < 0 or index >= size
  - concat
```
public final ByteString concat(ByteString other)
```
    Concatenate the given ByteString to this one. Short concatenations, of total size smaller than CONCATENATE_BY_COPY_SIZE, are produced by copying the underlying bytes (as per Rope.java, BAP95 . In general, the concatenate involves no copying.
    
    Parameters:
    
    other - string to concatenate
    
    Returns:
    
    a new ByteString instance
  - copyFrom
```
public static ByteString copyFrom(byte[] bytes)
```
    Copies the given bytes into a ByteString.
    
    Parameters:
    
    bytes - to copy
    
    Returns:
    
    new ByteString
  - copyFrom
```
public static ByteString copyFrom(byte[] bytes,
                                  int offset,
                                  int size)
```
    Copies the given bytes into a ByteString.
    
    Parameters:
    
    bytes - source array
    
    offset - offset in source array
    
    size - number of bytes to copy
    
    Returns:
    
    new ByteString
  - copyFrom
```
public static ByteString copyFrom(ByteBuffer bytes)
```
    Copies the remaining bytes from a java.nio.ByteBuffer into a ByteString.
    
    Parameters:
    
    bytes - sourceBuffer
    
    Returns:
    
    new ByteString
  - copyFrom
```
public static ByteString copyFrom(ByteBuffer bytes,
                                  int size)
```
    Copies the next size bytes from a java.nio.ByteBuffer into a ByteString.
    
    Parameters:
    
    bytes - source buffer
    
    size - number of bytes to copy
    
    Returns:
    
    new ByteString
  - copyFrom
```
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.
    
    Parameters:
    
    byteStrings - strings to be concatenated
    
    Returns:
    
    new ByteString
  - copyFrom
```
public static ByteString copyFrom(String text,
                                  String charsetName)
                           throws UnsupportedEncodingException
```
    Encodes text into a sequence of bytes using the named charset and returns the result as a ByteString.
    
    Parameters:
    
    text - source string
    
    charsetName - encoding to use
    
    Returns:
    
    new ByteString
    
    Throws:
    
    UnsupportedEncodingException - if the encoding isn't found
  - copyFromUtf8
```
public static ByteString copyFromUtf8(String text)
```
    Encodes text into a sequence of UTF-8 bytes and returns the result as a ByteString.
    
    Parameters:
    
    text - source string
    
    Returns:
    
    new ByteString
  - copyTo
```
public void copyTo(byte[] target,
                   int offset)
```
    Copies bytes into a buffer at the given offset.
    
    Parameters:
    
    target - buffer to copy into
    
    offset - in the target buffer
    
    Throws:
    
    IndexOutOfBoundsException - if the offset is negative or too large
  - copyTo
```
public final void copyTo(byte[] target,
                         int sourceOffset,
                         int targetOffset,
                         int numberToCopy)
```
    Copies bytes into a buffer.
    
    Parameters:
    
    target - buffer to copy into
    
    sourceOffset - offset within these bytes
    
    targetOffset - offset within the target buffer
    
    numberToCopy - number of bytes to copy
    
    Throws:
    
    IndexOutOfBoundsException - if an offset or size is negative or too large
  - copyTo
```
public abstract void copyTo(ByteBuffer target)
```
    Copies bytes into a ByteBuffer.
    
    Parameters:
    
    target - ByteBuffer to copy into.
    
    Throws:
    
    ReadOnlyBufferException - if the target is read-only
    
    BufferOverflowException - if the target's remaining() space is not large enough to hold the data.
  - copyToInternal
```
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.
  - endsWith
```
public final boolean endsWith(ByteString suffix)
```
    Tests if this bytestring ends with the specified suffix. Similar to String.endsWith(String)
    
    Parameters:
    
    suffix - the suffix.
    
    Returns:
    
    true if the byte sequence represented by the argument is a suffix of the byte sequence represented by this string; false otherwise.
  - equals
```
public abstract boolean equals(@Nullable
                               Object o)
```
    Description copied from class: Object
    Indicates whether some other object is "equal to" this one.
    The equals method implements an equivalence relation on non-null object references:
    - It is reflexive: for any non-null reference value x, x.equals(x) should return true.
    - It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
    - It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
    - It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
    - For any non-null reference value x, x.equals(null) should return false.
    The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).
    Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    o - the reference object with which to compare.
    
    Returns:
    
    true if this object is the same as the obj argument; false otherwise.
    
    See Also:
    
    Object.hashCode(), HashMap
  - 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:
    
    tree depth or zero
  - hashCode
```
public final int hashCode()
```
    Compute the hashCode using the traditional algorithm from ByteString.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    hashCode value
    
    See Also:
    
    Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)
  - 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:
    
    true if the tree is flat enough
  - isEmpty
```
public final boolean isEmpty()
```
    Returns true if the size is 0, false otherwise.
    
    Returns:
    
    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:
    
    whether the bytes in this ByteString are a well-formed UTF-8 byte sequence
  - iterator
```
public final 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 ByteString.ByteIterator.nextByte().
    
    Specified by:
    
    iterator in interface Iterable<Byte>
    
    Returns:
    
    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:
    
    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:
    
    an input stream that returns the bytes of this byte string.
  - newOutput
```
public static ByteString.Output newOutput()
```
    Creates a new ByteString.Output. Call ByteString.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:
    
    OutputStream for building a ByteString
  - newOutput
```
public static ByteString.Output newOutput(int initialCapacity)
```
    Creates a new ByteString.Output with the given initial capacity. Call ByteString.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.
    
    Parameters:
    
    initialCapacity - estimate of number of bytes to be written
    
    Returns:
    
    OutputStream for building a ByteString
  - partialHash
```
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:
    
    h - starting hash value
    
    offset - offset into this value to start looking at data values
    
    length - number of data values to include in the hash computation
    
    Returns:
    
    ending hash value
  - partialIsValidUtf8
```
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:
    
    state - either 0 (if this is the initial decoding operation) or the value returned from a call to a partial decoding method for the previous bytes
    
    offset - offset of the first byte to check
    
    length - number of bytes to check
    
    Returns:
    
    -1 if the partial byte sequence is definitely malformed, 0 if it is well-formed (no additional input needed), or, if the byte sequence is "incomplete", i.e. apparently terminated in the middle of a character, an opaque integer "state" value containing enough information to decode the character when passed to a subsequent invocation of a partial decoding method.
  - peekCachedHashCode
```
protected final int peekCachedHashCode()
```
    Return the cached hash code if available.
    
    Returns:
    
    value of cached hash code or 0 if not computed yet
  - readFrom
```
public static ByteString readFrom(InputStream streamToDrain)
                           throws IOException
```
    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.
    
    Parameters:
    
    streamToDrain - The source stream, which is read completely but not closed.
    
    Returns:
    
    A new ByteString which is made up of chunks of various sizes, depending on the behavior of the underlying stream.
    
    Throws:
    
    IOException - IOException is thrown if there is a problem reading the underlying stream.
  - readFrom
```
public static ByteString readFrom(InputStream streamToDrain,
                                  int chunkSize)
                           throws IOException
```
    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:
    
    streamToDrain - The source stream, which is read completely but not closed.
    
    chunkSize - The size of the chunks in which to read the stream.
    
    Returns:
    
    A new ByteString which is made up of chunks of the given size.
    
    Throws:
    
    IOException - IOException is thrown if there is a problem reading the underlying stream.
  - readFrom
```
public static ByteString readFrom(InputStream streamToDrain,
                                  int minChunkSize,
                                  int maxChunkSize)
                           throws IOException
```
    Throws:
    
    IOException
  - size
```
public abstract int size()
```
    Gets the number of bytes.
    
    Returns:
    
    size in bytes
  - startsWith
```
public final boolean startsWith(ByteString prefix)
```
    Tests if this bytestring starts with the specified prefix. Similar to String.startsWith(String)
    
    Parameters:
    
    prefix - the prefix.
    
    Returns:
    
    true if the byte sequence represented by the argument is a prefix of the byte sequence represented by this string; false otherwise.
  - substring
```
public final ByteString substring(int beginIndex)
```
    Return the substring from beginIndex, inclusive, to the end of the string.
    
    Parameters:
    
    beginIndex - start at this index
    
    Returns:
    
    substring sharing underlying data
    
    Throws:
    
    IndexOutOfBoundsException - if beginIndex < 0 or beginIndex > size().
  - substring
```
public abstract ByteString substring(int beginIndex,
                                     int endIndex)
```
    Return the substring from beginIndex, inclusive, to endIndex, exclusive.
    
    Parameters:
    
    beginIndex - start at this index
    
    endIndex - the last character is the one before this index
    
    Returns:
    
    substring sharing underlying data
    
    Throws:
    
    IndexOutOfBoundsException - if beginIndex < 0, endIndex > size(), or beginIndex > endIndex.
  - toByteArray
```
public final byte[] toByteArray()
```
    Copies bytes to a byte[].
    
    Returns:
    
    copied bytes
  - toString
```
public final String toString()
```
    Description copied from class: Object
    Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.
    The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:
    getClass().getName() + '@' + Integer.toHexString(hashCode())
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of the object.
  - toString
```
public final String toString(String charset)
                      throws UnsupportedEncodingException
```
    Constructs a new String by decoding the bytes using the specified charset. Returns the same empty String if empty.
    
    Parameters:
    
    charset - encode using this charset
    
    Returns:
    
    new string
    
    Throws:
    
    UnsupportedEncodingException
  - toStringInternal
```
protected abstract String toStringInternal(String charset)
                                    throws UnsupportedEncodingException
```
    Constructs a new String by decoding the bytes using the specified charset.
    
    Parameters:
    
    charset - encode using this charset
    
    Returns:
    
    new string
    
    Throws:
    
    UnsupportedEncodingException
  - toStringUtf8
```
public final String toStringUtf8()
```
    Constructs a new String by decoding the bytes as UTF-8.
    
    Returns:
    
    new string using UTF-8 encoding
  - writeTo
```
public abstract void writeTo(OutputStream out)
                      throws IOException
```
    Writes a copy of the contents of this byte string to the specified output stream argument.
    
    Parameters:
    
    out - the output stream to which to write the data.
    
    Throws:
    
    IOException - if an I/O error occurs.

Class ByteString

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EMPTY

Method Detail

asReadOnlyByteBuffer

asReadOnlyByteBufferList

byteAt

concat

copyFrom

copyFrom

copyFrom

copyFrom

copyFrom

copyFrom

copyFromUtf8

copyTo

copyTo

copyTo

copyToInternal

endsWith

equals

getTreeDepth

hashCode

isBalanced

isEmpty

isValidUtf8

iterator

newCodedInput

newInput

newOutput

newOutput

partialHash

partialIsValidUtf8

peekCachedHashCode

readFrom

readFrom

readFrom

size

startsWith

substring

substring

toByteArray

toString

toString

toStringInternal

toStringUtf8

writeTo