Class ByteString
- java.lang.Object
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- com.google.protobuf.ByteString
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- All Implemented Interfaces:
java.io.Serializable,java.lang.Iterable<java.lang.Byte>
@CheckReturnValue public abstract class ByteString extends java.lang.Object implements java.lang.Iterable<java.lang.Byte>, java.io.SerializableImmutable sequence of bytes. Provides conversions to and frombyte[],String,ByteBuffer,InputStream,OutputStream. Also provides a conversion toCodedInputStream.Like
String, the contents of aByteStringcan 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
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Nested Class Summary
Nested Classes Modifier and Type Class Description static interfaceByteString.ByteIteratorThis interface extendsIterator<Byte>, so that we can return an unboxedbyte.static classByteString.OutputOutputs to aByteStringinstance.
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Field Summary
Fields Modifier and Type Field Description static ByteStringEMPTYEmptyByteString.
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods Modifier and Type Method Description abstract java.nio.ByteBufferasReadOnlyByteBuffer()Constructs a read-onlyjava.nio.ByteBufferwhose content is equal to the contents of this byte string.abstract java.util.List<java.nio.ByteBuffer>asReadOnlyByteBufferList()Constructs a list of read-onlyjava.nio.ByteBufferobjects such that the concatenation of their contents is equal to the contents of this byte string.abstract bytebyteAt(int index)Gets the byte at the given index.ByteStringconcat(ByteString other)Concatenate the givenByteStringto this one.static ByteStringcopyFrom(byte[] bytes)Copies the given bytes into aByteString.static ByteStringcopyFrom(byte[] bytes, int offset, int size)Copies the given bytes into aByteString.static ByteStringcopyFrom(java.lang.Iterable<ByteString> byteStrings)Concatenates all byte strings in the iterable and returns the result.static ByteStringcopyFrom(java.lang.String text, java.lang.String charsetName)Encodestextinto a sequence of bytes using the named charset and returns the result as aByteString.static ByteStringcopyFrom(java.lang.String text, java.nio.charset.Charset charset)Encodestextinto a sequence of bytes using the named charset and returns the result as aByteString.static ByteStringcopyFrom(java.nio.ByteBuffer bytes)Copies the remaining bytes from ajava.nio.ByteBufferinto aByteString.static ByteStringcopyFrom(java.nio.ByteBuffer bytes, int size)Copies the nextsizebytes from ajava.nio.ByteBufferinto aByteString.static ByteStringcopyFromUtf8(java.lang.String text)Encodestextinto a sequence of UTF-8 bytes and returns the result as aByteString.voidcopyTo(byte[] target, int offset)Copies bytes into a buffer at the given offset.voidcopyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)Deprecated.Instead, callbyteString.substring(sourceOffset, sourceOffset + numberToCopy).copyTo(target, targetOffset)abstract voidcopyTo(java.nio.ByteBuffer target)Copies bytes into a ByteBuffer.protected abstract voidcopyToInternal(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)Internal (package private) implementation ofcopyTo(byte[],int,int,int).static ByteStringempty()Returns an emptyByteStringof size0.booleanendsWith(ByteString suffix)Tests if this bytestring ends with the specified suffix.abstract booleanequals(java.lang.Object o)static ByteStringfromHex(java.lang.String hexString)Returns aByteStringfrom a hexadecimal String.protected abstract intgetTreeDepth()Return the depth of the tree representing thisByteString, if any, whose root is this node.inthashCode()Compute the hashCode using the traditional algorithm fromByteString.protected abstract booleanisBalanced()Returntrueif this ByteString is literal (a leaf node) or a flat-enough tree in the sense ofRopeByteString.booleanisEmpty()Returnstrueif the size is0,falseotherwise.abstract booleanisValidUtf8()Tells whether thisByteStringrepresents 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.ByteIteratoriterator()Return aByteString.ByteIteratorover the bytes in the ByteString.abstract CodedInputStreamnewCodedInput()Creates aCodedInputStreamwhich can be used to read the bytes.abstract java.io.InputStreamnewInput()Creates anInputStreamwhich can be used to read the bytes.static ByteString.OutputnewOutput()Creates a newByteString.Output.static ByteString.OutputnewOutput(int initialCapacity)Creates a newByteString.Outputwith the given initial capacity.protected abstract intpartialHash(int h, int offset, int length)Compute the hash across the value bytes starting with the given hash, and return the result.protected abstract intpartialIsValidUtf8(int state, int offset, int length)Tells whether the given byte sequence is a well-formed, malformed, or incomplete UTF-8 byte sequence.protected intpeekCachedHashCode()Return the cached hash code if available.static ByteStringreadFrom(java.io.InputStream streamToDrain)Completely reads the given stream's bytes into aByteString, blocking if necessary until all bytes are read through to the end of the stream.static ByteStringreadFrom(java.io.InputStream streamToDrain, int chunkSize)Completely reads the given stream's bytes into aByteString, blocking if necessary until all bytes are read through to the end of the stream.static ByteStringreadFrom(java.io.InputStream streamToDrain, int minChunkSize, int maxChunkSize)Helper method that takes the chunk size range as a parameter.abstract intsize()Gets the number of bytes.booleanstartsWith(ByteString prefix)Tests if this bytestring starts with the specified prefix.ByteStringsubstring(int beginIndex)Return the substring frombeginIndex, inclusive, to the end of the string.abstract ByteStringsubstring(int beginIndex, int endIndex)Return the substring frombeginIndex, inclusive, toendIndex, exclusive.byte[]toByteArray()Copies bytes to abyte[].java.lang.StringtoString()java.lang.StringtoString(java.lang.String charsetName)Constructs a newStringby decoding the bytes using the specified charset.java.lang.StringtoString(java.nio.charset.Charset charset)Constructs a newStringby decoding the bytes using the specified charset.protected abstract java.lang.StringtoStringInternal(java.nio.charset.Charset charset)Constructs a newStringby decoding the bytes using the specified charset.java.lang.StringtoStringUtf8()Constructs a newStringby decoding the bytes as UTF-8.static java.util.Comparator<ByteString>unsignedLexicographicalComparator()Returns aComparatorwhich comparesByteString-s lexicographically as sequences of unsigned bytes (i.e.abstract voidwriteTo(java.io.OutputStream out)Writes a copy of the contents of this byte string to the specified output stream argument.
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Field Detail
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EMPTY
public static final ByteString EMPTY
EmptyByteString.
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Method Detail
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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 theByteString.ByteIteratorreturned byiterator(), and callsubstring(int, int)first if necessary.- Parameters:
index- index of byte- Returns:
- the value
- Throws:
java.lang.IndexOutOfBoundsException-index < 0 or index >= size
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iterator
public ByteString.ByteIterator iterator()
Return aByteString.ByteIteratorover the bytes in the ByteString. To avoid auto-boxing, you may get the iterator manually and callByteString.ByteIterator.nextByte().- Specified by:
iteratorin interfacejava.lang.Iterable<java.lang.Byte>- Returns:
- the iterator
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size
public abstract int size()
Gets the number of bytes.- Returns:
- size in bytes
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isEmpty
public final boolean isEmpty()
Returnstrueif the size is0,falseotherwise.- Returns:
- true if this is zero bytes long
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empty
public static final ByteString empty()
Returns an emptyByteStringof size0.
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unsignedLexicographicalComparator
public static java.util.Comparator<ByteString> unsignedLexicographicalComparator()
Returns aComparatorwhich comparesByteString-s lexicographically as sequences of unsigned bytes (i.e. values between 0 and 255, inclusive).For example,
(byte) -1is considered to be greater than(byte) 1because it is interpreted as an unsigned value,255:`-1` -> 0b11111111 (two's complement) -> 255`1` -> 0b00000001 -> 1
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substring
public final ByteString substring(int beginIndex)
Return the substring frombeginIndex, inclusive, to the end of the string.- Parameters:
beginIndex- start at this index- Returns:
- substring sharing underlying data
- Throws:
java.lang.IndexOutOfBoundsException- ifbeginIndex < 0orbeginIndex > size().
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substring
public abstract ByteString substring(int beginIndex, int endIndex)
Return the substring frombeginIndex, inclusive, toendIndex, exclusive.- Parameters:
beginIndex- start at this indexendIndex- the last character is the one before this index- Returns:
- substring sharing underlying data
- Throws:
java.lang.IndexOutOfBoundsException- ifbeginIndex < 0,endIndex > size(), orbeginIndex > endIndex.
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startsWith
public final boolean startsWith(ByteString prefix)
Tests if this bytestring starts with the specified prefix. Similar toString.startsWith(String)- Parameters:
prefix- the prefix.- Returns:
trueif the byte sequence represented by the argument is a prefix of the byte sequence represented by this string;falseotherwise.
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endsWith
public final boolean endsWith(ByteString suffix)
Tests if this bytestring ends with the specified suffix. Similar toString.endsWith(String)- Parameters:
suffix- the suffix.- Returns:
trueif the byte sequence represented by the argument is a suffix of the byte sequence represented by this string;falseotherwise.
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fromHex
public static ByteString fromHex(@CompileTimeConstant java.lang.String hexString)
Returns aByteStringfrom a hexadecimal String. Alternative CharSequences should useByteStrings#decode(CharSequence, BaseEncoding)- Parameters:
hexString- String of hexadecimal digits to createByteStringfrom.- Throws:
java.lang.NumberFormatException- if the hexString does not contain a parsable hex String.
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copyFrom
public static ByteString copyFrom(byte[] bytes, int offset, int size)
Copies the given bytes into aByteString.- Parameters:
bytes- source arrayoffset- offset in source arraysize- number of bytes to copy- Returns:
- new
ByteString - Throws:
java.lang.IndexOutOfBoundsException- ifoffsetorsizeare out of bounds
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copyFrom
public static ByteString copyFrom(byte[] bytes)
Copies the given bytes into aByteString.- Parameters:
bytes- to copy- Returns:
- new
ByteString
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copyFrom
public static ByteString copyFrom(java.nio.ByteBuffer bytes, int size)
Copies the nextsizebytes from ajava.nio.ByteBufferinto aByteString.- Parameters:
bytes- source buffersize- number of bytes to copy- Returns:
- new
ByteString - Throws:
java.lang.IndexOutOfBoundsException- ifsize > bytes.remaining()
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copyFrom
public static ByteString copyFrom(java.nio.ByteBuffer bytes)
Copies the remaining bytes from ajava.nio.ByteBufferinto aByteString.- Parameters:
bytes- sourceBuffer- Returns:
- new
ByteString
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copyFrom
public static ByteString copyFrom(java.lang.String text, java.lang.String charsetName) throws java.io.UnsupportedEncodingException
Encodestextinto a sequence of bytes using the named charset and returns the result as aByteString.- Parameters:
text- source stringcharsetName- encoding to use- Returns:
- new
ByteString - Throws:
java.io.UnsupportedEncodingException- if the encoding isn't found
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copyFrom
public static ByteString copyFrom(java.lang.String text, java.nio.charset.Charset charset)
Encodestextinto a sequence of bytes using the named charset and returns the result as aByteString.- Parameters:
text- source stringcharset- encode using this charset- Returns:
- new
ByteString
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copyFromUtf8
public static ByteString copyFromUtf8(java.lang.String text)
Encodestextinto a sequence of UTF-8 bytes and returns the result as aByteString.- Parameters:
text- source string- Returns:
- new
ByteString
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readFrom
public static ByteString readFrom(java.io.InputStream streamToDrain) throws java.io.IOException
Completely reads the given stream's bytes into aByteString, blocking if necessary until all bytes are read through to the end of the stream.Performance notes: The returned
ByteStringis 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
ByteStringwhich is made up of chunks of various sizes, depending on the behavior of the underlying stream. - Throws:
java.io.IOException- if there is a problem reading the underlying streamjava.lang.IllegalArgumentException- if the stream supplies more than Integer.MAX_VALUE bytes
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readFrom
public static ByteString readFrom(java.io.InputStream streamToDrain, int chunkSize) throws java.io.IOException
Completely reads the given stream's bytes into aByteString, blocking if necessary until all bytes are read through to the end of the stream.Performance notes: The returned
ByteStringis 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
ByteStringwhich is made up of chunks of the given size. - Throws:
java.io.IOException- if there is a problem reading the underlying streamjava.lang.IllegalArgumentException- if the stream supplies more than Integer.MAX_VALUE bytes
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readFrom
public static ByteString readFrom(java.io.InputStream streamToDrain, int minChunkSize, int maxChunkSize) throws java.io.IOException
Helper method that takes the chunk size range as a parameter.- Parameters:
streamToDrain- the source stream, which is read completely but not closedminChunkSize- the minimum size of the chunks in which to read the streammaxChunkSize- the maximum size of the chunks in which to read the stream- Returns:
- a new
ByteStringwhich is made up of chunks within the given size range - Throws:
java.io.IOException- if there is a problem reading the underlying streamjava.lang.IllegalArgumentException- if the stream supplies more than Integer.MAX_VALUE bytes
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concat
public final ByteString concat(ByteString other)
Concatenate the givenByteStringto this one. Short concatenations, of total size smaller thanCONCATENATE_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
ByteStringinstance - Throws:
java.lang.IllegalArgumentException- if the combined size of the two byte strings exceeds Integer.MAX_VALUE
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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
ByteStringis not necessarily a unique object. If the list is empty, the returned object is the singleton emptyByteString. If the list has only one element, thatByteStringwill be returned without copying.- Parameters:
byteStrings- strings to be concatenated- Returns:
- new
ByteString - Throws:
java.lang.IllegalArgumentException- if the combined size of the byte strings exceeds Integer.MAX_VALUE
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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 intooffset- in the target buffer- Throws:
java.lang.IndexOutOfBoundsException- if the offset is negative or too large
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copyTo
@Deprecated public final void copyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)Deprecated.Instead, callbyteString.substring(sourceOffset, sourceOffset + numberToCopy).copyTo(target, targetOffset)Copies bytes into a buffer.- Parameters:
target- buffer to copy intosourceOffset- offset within these bytestargetOffset- offset within the target buffernumberToCopy- number of bytes to copy- Throws:
java.lang.IndexOutOfBoundsException- if an offset or size is negative or too large
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copyToInternal
protected abstract void copyToInternal(byte[] target, int sourceOffset, int targetOffset, int numberToCopy)Internal (package private) implementation ofcopyTo(byte[],int,int,int). It assumes that all error checking has already been performed and thatnumberToCopy > 0.
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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 thetargetis read-onlyjava.nio.BufferOverflowException- if thetarget's remaining() space is not large enough to hold the data.
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toByteArray
public final byte[] toByteArray()
Copies bytes to abyte[].- Returns:
- copied bytes
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writeTo
public abstract void writeTo(java.io.OutputStream out) throws java.io.IOExceptionWrites 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.
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asReadOnlyByteBuffer
public abstract java.nio.ByteBuffer asReadOnlyByteBuffer()
Constructs a read-onlyjava.nio.ByteBufferwhose 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
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asReadOnlyByteBufferList
public abstract java.util.List<java.nio.ByteBuffer> asReadOnlyByteBufferList()
Constructs a list of read-onlyjava.nio.ByteBufferobjects 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
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toString
public final java.lang.String toString(java.lang.String charsetName) throws java.io.UnsupportedEncodingExceptionConstructs a newStringby 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
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toString
public final java.lang.String toString(java.nio.charset.Charset charset)
Constructs a newStringby decoding the bytes using the specified charset. Returns the same empty String if empty.- Parameters:
charset- encode using this charset- Returns:
- new string
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toStringInternal
protected abstract java.lang.String toStringInternal(java.nio.charset.Charset charset)
Constructs a newStringby decoding the bytes using the specified charset.- Parameters:
charset- encode using this charset- Returns:
- new string
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toStringUtf8
public final java.lang.String toStringUtf8()
Constructs a newStringby decoding the bytes as UTF-8.- Returns:
- new string using UTF-8 encoding
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isValidUtf8
public abstract boolean isValidUtf8()
Tells whether thisByteStringrepresents 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
truewhenever:Arrays.equals(byteString.toByteArray(), new String(byteString.toByteArray(), "UTF-8").getBytes("UTF-8"))This method returns
falsefor "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
ByteStringare a well-formed UTF-8 byte sequence
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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 multipleByteStringsegments.- Parameters:
state- either0(if this is the initial decoding operation) or the value returned from a call to a partial decoding method for the previous bytesoffset- offset of the first byte to checklength- number of bytes to check- Returns:
-1if the partial byte sequence is definitely malformed,0if 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.
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equals
public abstract boolean equals(java.lang.Object o)
- Overrides:
equalsin classjava.lang.Object
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hashCode
public final int hashCode()
Compute the hashCode using the traditional algorithm fromByteString.- Overrides:
hashCodein classjava.lang.Object- Returns:
- hashCode value
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newInput
public abstract java.io.InputStream newInput()
Creates anInputStreamwhich can be used to read the bytes.The
InputStreamreturned by this method is guaranteed to be completely non-blocking. The methodInputStream.available()returns the number of bytes remaining in the stream. The methodsInputStream.read(byte[]),InputStream.read(byte[],int,int)andInputStream.skip(long)will read/skip as many bytes as are available. The methodInputStream.markSupported()returnstrue.The methods in the returned
InputStreammight not be thread safe.- Returns:
- an input stream that returns the bytes of this byte string.
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newCodedInput
public abstract CodedInputStream newCodedInput()
Creates aCodedInputStreamwhich can be used to read the bytes. Using this is often more efficient than creating aCodedInputStreamthat wraps the result ofnewInput().- Returns:
- stream based on wrapped data
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newOutput
public static ByteString.Output newOutput(int initialCapacity)
Creates a newByteString.Outputwith the given initial capacity. CallByteString.Output.toByteString()to create theByteStringinstance.A
ByteString.Outputoffers the same functionality as aByteArrayOutputStream, except that it returns aByteStringrather than abytearray.- Parameters:
initialCapacity- estimate of number of bytes to be written- Returns:
OutputStreamfor building aByteString
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newOutput
public static ByteString.Output newOutput()
Creates a newByteString.Output. CallByteString.Output.toByteString()to create theByteStringinstance.A
ByteString.Outputoffers the same functionality as aByteArrayOutputStream, except that it returns aByteStringrather than abyte array.- Returns:
OutputStreamfor building aByteString
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getTreeDepth
protected abstract int getTreeDepth()
Return the depth of the tree representing thisByteString, if any, whose root is this node. If this is a leaf node, return 0.- Returns:
- tree depth or zero
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isBalanced
protected abstract boolean isBalanced()
Returntrueif this ByteString is literal (a leaf node) or a flat-enough tree in the sense ofRopeByteString.- Returns:
- true if the tree is flat enough
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peekCachedHashCode
protected final int peekCachedHashCode()
Return the cached hash code if available.- Returns:
- value of cached hash code or 0 if not computed yet
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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 valueoffset- offset into this value to start looking at data valueslength- number of data values to include in the hash computation- Returns:
- ending hash value
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toString
public final java.lang.String toString()
- Overrides:
toStringin classjava.lang.Object
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