ByteString

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

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<java.lang.Byte>
```
public abstract class ByteString
extends java.lang.Object
implements java.lang.Iterable<java.lang.Byte>, java.io.Serializable
```
Immutable sequence of bytes. Provides conversions to and from byte[], 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.

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 Deprecated Methods
Modifier and Type	Method and Description
`abstract java.nio.ByteBuffer`	`asReadOnlyByteBuffer()` Constructs a read-only `java.nio.ByteBuffer` whose content is equal to the contents of this byte string.
`abstract java.util.List<java.nio.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(java.nio.ByteBuffer bytes)` Copies the remaining bytes from a `java.nio.ByteBuffer` into a `ByteString`.
`static ByteString`	`copyFrom(java.nio.ByteBuffer bytes, int size)` Copies the next `size` bytes from a `java.nio.ByteBuffer` into a `ByteString`.
`static ByteString`	`copyFrom(java.lang.Iterable<ByteString> byteStrings)` Concatenates all byte strings in the iterable and returns the result.
`static ByteString`	`copyFrom(java.lang.String text, java.nio.charset.Charset charset)` Encodes `text` into a sequence of bytes using the named charset and returns the result as a `ByteString`.
`static ByteString`	`copyFrom(java.lang.String text, java.lang.String charsetName)` Encodes `text` into a sequence of bytes using the named charset and returns the result as a `ByteString`.
`static ByteString`	`copyFromUtf8(java.lang.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)` Deprecated. Instead, call `byteString.substring(sourceOffset, sourceOffset + numberToCopy).copyTo(target, targetOffset)`
`abstract void`	`copyTo(java.nio.ByteBuffer target)` Copies bytes into a ByteBuffer.
`boolean`	`endsWith(ByteString suffix)` Tests if this bytestring ends with the specified suffix.
`abstract boolean`	`equals(java.lang.Object o)`
`int`	`hashCode()` Compute the hashCode using the traditional algorithm from `ByteString`.
`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 java.io.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.
`static ByteString`	`readFrom(java.io.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(java.io.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(java.io.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[]`.
`java.lang.String`	`toString()`
`java.lang.String`	`toString(java.nio.charset.Charset charset)` Constructs a new `String` by decoding the bytes using the specified charset.
`java.lang.String`	`toString(java.lang.String charsetName)` Constructs a new `String` by decoding the bytes using the specified charset.
`java.lang.String`	`toStringUtf8()` Constructs a new `String` by decoding the bytes as UTF-8.
`static java.util.Comparator<ByteString>`	`unsignedLexicographicalComparator()` Returns a `Comparator` which compares `ByteString`-s lexicographically as sequences of unsigned bytes (i.e.
`abstract void`	`writeTo(java.io.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
getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Field Detail
  - EMPTY
```
public static final ByteString EMPTY
```
    Empty ByteString.
- Method Detail
  - 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:
    
    java.lang.IndexOutOfBoundsException - index < 0 or index >= size
  - 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 ByteString.ByteIterator.nextByte().
    
    Specified by:
    
    iterator in interface java.lang.Iterable<java.lang.Byte>
    
    Returns:
    
    the iterator
  - size
```
public abstract int size()
```
    Gets the number of bytes.
    
    Returns:
    
    size in bytes
  - isEmpty
```
public final boolean isEmpty()
```
    Returns true if the size is 0, false otherwise.
    
    Returns:
    
    true if this is zero bytes long
  - unsignedLexicographicalComparator
```
public static java.util.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) -> 255
    - `1` -> 0b00000001 -> 1
  - 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:
    
    java.lang.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:
    
    java.lang.IndexOutOfBoundsException - if beginIndex < 0, endIndex > size(), or beginIndex > endIndex.
  - 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.
  - 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.
  - 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
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if offset or size are out of bounds
  - 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(java.nio.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
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if size > bytes.remaining()
  - copyFrom
```
public static ByteString copyFrom(java.nio.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(java.lang.String text,
                                  java.lang.String charsetName)
                           throws java.io.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:
    
    java.io.UnsupportedEncodingException - if the encoding isn't found
  - copyFrom
```
public static ByteString copyFrom(java.lang.String text,
                                  java.nio.charset.Charset charset)
```
    Encodes text into a sequence of bytes using the named charset and returns the result as a ByteString.
    
    Parameters:
    
    text - source string
    
    charset - encode using this charset
    
    Returns:
    
    new ByteString
  - copyFromUtf8
```
public static ByteString copyFromUtf8(java.lang.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
  - readFrom
```
public static ByteString readFrom(java.io.InputStream streamToDrain)
                           throws java.io.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:
    
    java.io.IOException - IOException is thrown if there is a problem reading the underlying stream.
  - readFrom
```
public static ByteString readFrom(java.io.InputStream streamToDrain,
                                  int chunkSize)
                           throws java.io.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:
    
    java.io.IOException - IOException is thrown if there is a problem reading the underlying stream.
  - readFrom
```
public static ByteString readFrom(java.io.InputStream streamToDrain,
                                  int minChunkSize,
                                  int maxChunkSize)
                           throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - 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(java.lang.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
  - copyTo
```
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:
    
    target - buffer to copy into
    
    offset - in the target buffer
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the offset is negative or too large
  - copyTo
```
@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:
    
    target - buffer to copy into
    
    sourceOffset - offset within these bytes
    
    targetOffset - offset within the target buffer
    
    numberToCopy - number of bytes to copy
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if an offset or size is negative or too large
  - copyTo
```
public abstract void copyTo(java.nio.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)
    
    Parameters:
    
    target - ByteBuffer to copy into.
    
    Throws:
    
    java.nio.ReadOnlyBufferException - if the target is read-only
    
    java.nio.BufferOverflowException - if the target's remaining() space is not large enough to hold the data.
  - toByteArray
```
public final byte[] toByteArray()
```
    Copies bytes to a byte[].
    
    Returns:
    
    copied bytes
  - writeTo
```
public abstract void writeTo(java.io.OutputStream out)
                      throws java.io.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:
    
    java.io.IOException - if an I/O error occurs.
  - asReadOnlyByteBuffer
```
public abstract java.nio.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 java.util.List<java.nio.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
  - toString
```
public final java.lang.String toString(java.lang.String charsetName)
                                throws java.io.UnsupportedEncodingException
```
    Constructs a new String by decoding the bytes using the specified charset.
    
    Parameters:
    
    charsetName - encode using this charset
    
    Returns:
    
    new string
    
    Throws:
    
    java.io.UnsupportedEncodingException - if charset isn't recognized
  - toString
```
public final java.lang.String toString(java.nio.charset.Charset charset)
```
    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
  - toStringUtf8
```
public final java.lang.String toStringUtf8()
```
    Constructs a new String by decoding the bytes as UTF-8.
    
    Returns:
    
    new string using UTF-8 encoding
  - 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
  - equals
```
public abstract boolean equals(java.lang.Object o)
```
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public final int hashCode()
```
    Compute the hashCode using the traditional algorithm from ByteString.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    hashCode value
  - newInput
```
public abstract java.io.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.
  - 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
  - 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
  - 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
  - toString
```
public final java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class ByteString

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Field Detail

EMPTY

Method Detail

byteAt

iterator

size

isEmpty

unsignedLexicographicalComparator

substring

substring

startsWith

endsWith

copyFrom

copyFrom

copyFrom

copyFrom

copyFrom

copyFrom

copyFromUtf8

readFrom

readFrom

readFrom

concat

copyFrom

copyTo

copyTo

copyTo

toByteArray

writeTo

asReadOnlyByteBuffer

asReadOnlyByteBufferList

toString

toString

toStringUtf8

isValidUtf8

equals

hashCode

newInput

newCodedInput

newOutput

newOutput

toString