Bits

java.lang.Object
- com.fr.third.jgroups.util.Bits

```
public class Bits
extends java.lang.Object
```
Class (similar to java.nio.Bits) containing helper methods to encode variables (e.g. ints, long, List<Address> etc) to memory (byte buffer) or output streams and read variables from memory or input streams.
The write methods write a type (e.g. an int or a char) to a buffer (ByteBuffer or output stream, using variable-length encoding. If there are not enough byte in the buffer to write a type, a BufferOverflowException is thrown. If the variable cannot be written to the output stream, an IOException is thrown.
The read methods read a variable-length encoded type from a buffer or input stream. If there are fewer bytes in the buffer than needed to read the type, a BufferUnderflowException is thrown. If the read fails, an IOException is thrown.
The size() methods return the number of bytes used to encode the given type with variable-length encoding.
There are additional helper methods to write/read custom JGroups types, e.g. address lists, Views etc
Note that methods to read/write atomic types (char, int etc) should only be used if variable-length encoding is desired; otherwise DataOutput.writeInt(int) or ByteBuffer.putInt(int) should be used instead.
At the time of writing this (Feb 2014), most methods have not yet been implemented.

从以下版本开始:

3.5

作者:

Bela Ban, Sanne Grinovero

构造器概要

构造器
构造器和说明

Bits()

构造器
构造器和说明
`Bits()`

方法概要

方法
限定符和类型	方法和说明
`protected static byte`	`bytesRequiredFor(int number)`
`protected static byte`	`bytesRequiredFor(long number)`
`protected static byte[]`	`decodeLength(byte len)`
`protected static byte`	`encodeLength(byte len1, byte len2)` Encodes the number of bytes needed into a single byte.
`protected static byte`	`getByteAt(long num, int index)`
`static int`	`makeInt(byte[] buf, int offset, int bytes_to_read)`
`static long`	`makeLong(byte[] buf, int offset, int bytes_to_read)`
`static short`	`makeShort(byte a)`
`static short`	`makeShort(byte a, byte b)`
`static AsciiString`	`readAsciiString(java.nio.ByteBuffer buf)` Reads an AsciiString from buf.
`static AsciiString`	`readAsciiString(java.io.DataInput in)` Reads an AsciiString from buf.
`static char`	`readChar(java.nio.ByteBuffer buf)` Reads a char from a buffer.
`static char`	`readChar(java.io.DataInput in)` Reads a char from an input stream
`static double`	`readDouble(java.nio.ByteBuffer buf)` Reads a double from a buffer.
`static double`	`readDouble(java.io.DataInput in)` Reads a double from an input stream
`static float`	`readFloat(java.nio.ByteBuffer buf)` Reads a a float from a buffer.
`static float`	`readFloat(java.io.DataInput in)` Reads a a float from an input stream.
`static int`	`readInt(java.nio.ByteBuffer buf)` Reads an int from a buffer.
`static int`	`readInt(java.io.DataInput in)` Reads an int from an input stream
`static long`	`readLong(java.nio.ByteBuffer buf)` Reads a long from a buffer.
`static long`	`readLong(java.io.DataInput in)` Reads a variable-length encoded long from an input stream.
`static long[]`	`readLongSequence(java.nio.ByteBuffer buf)` Reads 2 compressed longs from buf.
`static long[]`	`readLongSequence(java.io.DataInput in)` Reads 2 compressed longs from in.
`static short`	`readShort(java.nio.ByteBuffer buf)` Reads a short from a buffer.
`static short`	`readShort(java.io.DataInput in)` Reads a short from an input stream
`static java.lang.String`	`readString(java.nio.ByteBuffer buf)` Reads a string from buf.
`static java.lang.String`	`readString(java.io.DataInput in)` Reads a string from buf.
`static int`	`readUnsignedShort(java.nio.ByteBuffer buf)` Reads an unsigned short from a buffer.
`static int`	`readUnsignedShort(java.io.DataInput in)` Reads an unsigned short from an input stream
`static int`	`size(AsciiString str)` Measures the number of bytes required to encode an AsciiSring.
`static int`	`size(char ch)` Computes the size of a variable-length encoded character
`static int`	`size(double num)` Computes the size of a variable-length encoded double
`static int`	`size(float num)` Computes the size of a variable-length encoded float
`static int`	`size(int num)` Computes the size of a variable-length encoded int
`static int`	`size(long num)` Computes the size of a variable-length encoded long.
`static byte`	`size(long hd, long hr)`
`static int`	`size(short num)` Computes the size of a variable-length encoded short
`static int`	`sizeUTF(java.lang.String str)` Measures the number of bytes required to encode a string, taking multibyte characters into account.
`static void`	`writeAsciiString(AsciiString s, java.nio.ByteBuffer buf)` Writes an AsciiString to buf.
`static void`	`writeAsciiString(AsciiString s, java.io.DataOutput out)` Writes an AsciiString to buf.
`static void`	`writeChar(char ch, java.nio.ByteBuffer buf)` Writes a char to a ByteBuffer
`static void`	`writeChar(char ch, java.io.DataOutput out)` Writes a char to an output stream
`static void`	`writeDouble(double num, java.nio.ByteBuffer buf)` Writes a double to a ByteBuffer
`static void`	`writeDouble(double num, java.io.DataOutput out)` Writes a double to an output stream
`static void`	`writeFloat(float num, java.nio.ByteBuffer buf)` Writes a float to a ByteBuffer
`static void`	`writeFloat(float num, java.io.DataOutput out)` Writes a float to an output stream
`static void`	`writeInt(int num, java.nio.ByteBuffer buf)` Writes an int to a ByteBuffer
`static void`	`writeInt(int num, java.io.DataOutput out)` Writes an int to an output stream
`static void`	`writeLong(long num, java.nio.ByteBuffer buf)` Writes a long to a ByteBuffer
`static void`	`writeLong(long num, java.io.DataOutput out)` Writes a long to out in variable-length encoding.
`static void`	`writeLongSequence(long hd, long hr, java.nio.ByteBuffer buf)` Writes 2 sequence numbers (seqnos) in compressed format to buf.
`static void`	`writeLongSequence(long hd, long hr, java.io.DataOutput out)` Writes 2 sequence numbers (seqnos) in compressed format to an output stream.
`static void`	`writeShort(short num, java.nio.ByteBuffer buf)` Writes a short to a ByteBuffer
`static void`	`writeShort(short num, java.io.DataOutput out)` Writes a short to an output stream
`static void`	`writeString(java.lang.String s, java.nio.ByteBuffer buf)` Writes a string to buf.
`static void`	`writeString(java.lang.String s, java.io.DataOutput out)` Writes a string to buf.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - Bits
```
public Bits()
```
- 方法详细资料
  - writeChar
```
public static void writeChar(char ch,
             java.nio.ByteBuffer buf)
```
    Writes a char to a ByteBuffer
    
    参数:
    ch - the character to be written
    buf - the buffer
  - writeChar
```
public static void writeChar(char ch,
             java.io.DataOutput out)
                      throws java.io.IOException
```
    Writes a char to an output stream
    
    参数:
    ch - the character to be written
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readChar
```
public static char readChar(java.nio.ByteBuffer buf)
```
    Reads a char from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the character read from the buffer
  - readChar
```
public static char readChar(java.io.DataInput in)
                     throws java.io.IOException
```
    Reads a char from an input stream
    
    参数:
    in - the input stream
    
    返回:
    the character read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(char ch)
```
    Computes the size of a variable-length encoded character
    
    参数:
    ch - the character
    
    返回:
    the number of bytes needed to variable-length encode the char
  - writeShort
```
public static void writeShort(short num,
              java.nio.ByteBuffer buf)
```
    Writes a short to a ByteBuffer
    
    参数:
    num - the short to be written
    buf - the buffer
  - writeShort
```
public static void writeShort(short num,
              java.io.DataOutput out)
                       throws java.io.IOException
```
    Writes a short to an output stream
    
    参数:
    num - the short to be written
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readShort
```
public static short readShort(java.nio.ByteBuffer buf)
```
    Reads a short from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the short read from the buffer
  - readShort
```
public static short readShort(java.io.DataInput in)
                       throws java.io.IOException
```
    Reads a short from an input stream
    
    参数:
    in - the input stream
    
    返回:
    the short read from the input stream
    
    抛出:
    
    java.io.IOException
  - readUnsignedShort
```
public static int readUnsignedShort(java.nio.ByteBuffer buf)
```
    Reads an unsigned short from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the short read from the buffer
  - readUnsignedShort
```
public static int readUnsignedShort(java.io.DataInput in)
                             throws java.io.IOException
```
    Reads an unsigned short from an input stream
    
    参数:
    in - the input stream
    
    返回:
    the short read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(short num)
```
    Computes the size of a variable-length encoded short
    
    参数:
    num - the short
    
    返回:
    the number of bytes needed to variable-length encode num
  - makeShort
```
public static short makeShort(byte a,
              byte b)
```
  - makeShort
```
public static short makeShort(byte a)
```
  - writeInt
```
public static void writeInt(int num,
            java.nio.ByteBuffer buf)
```
    Writes an int to a ByteBuffer
    
    参数:
    num - the int to be written
    buf - the buffer
  - writeInt
```
public static void writeInt(int num,
            java.io.DataOutput out)
                     throws java.io.IOException
```
    Writes an int to an output stream
    
    参数:
    num - the int to be written
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readInt
```
public static int readInt(java.nio.ByteBuffer buf)
```
    Reads an int from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the int read from the buffer
  - readInt
```
public static int readInt(java.io.DataInput in)
                   throws java.io.IOException
```
    Reads an int from an input stream
    
    参数:
    in - the input stream
    
    返回:
    the int read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(int num)
```
    Computes the size of a variable-length encoded int
    
    参数:
    num - the int
    
    返回:
    the number of bytes needed to variable-length encode num
  - writeLong
```
public static void writeLong(long num,
             java.nio.ByteBuffer buf)
```
    Writes a long to a ByteBuffer
    
    参数:
    num - the long to be written
    buf - the buffer
  - writeLong
```
public static void writeLong(long num,
             java.io.DataOutput out)
                      throws java.io.IOException
```
    Writes a long to out in variable-length encoding. Note that currently variable-length encoding is not used (a similar mechanism is used); this will be implemented later.
    
    参数:
    num - the long
    out - the output stream to write num to
    
    抛出:
    
    java.io.IOException
  - readLong
```
public static long readLong(java.nio.ByteBuffer buf)
```
    Reads a long from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the long read from the buffer
  - readLong
```
public static long readLong(java.io.DataInput in)
                     throws java.io.IOException
```
    Reads a variable-length encoded long from an input stream. Note that currently variable-length encoding is not used (a similar mechanism is used); this will be implemented later.
    
    参数:
    in - the input stream
    
    返回:
    the long read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(long num)
```
    Computes the size of a variable-length encoded long. Note that this is not currently using variable-length encoding (will be implemented later).
    
    参数:
    num - the long
    
    返回:
    the number of bytes needed to variable-length encode num
  - writeLongSequence
```
public static void writeLongSequence(long hd,
                     long hr,
                     java.nio.ByteBuffer buf)
```
    Writes 2 sequence numbers (seqnos) in compressed format to buf. The seqnos are non-negative and hr is guaranteed to be >= hd.
    Once variable-length encoding has been implemented, this method will probably get dropped as we can simply write the 2 longs individually.
    
    参数:
    hd - the highest delivered seqno. Guaranteed to be a positive number
    hr - the highest received seqno. Guaranteed to be a positive number. Greater than or equal to hd
    buf - the buffer to write to
  - writeLongSequence
```
public static void writeLongSequence(long hd,
                     long hr,
                     java.io.DataOutput out)
                              throws java.io.IOException
```
    Writes 2 sequence numbers (seqnos) in compressed format to an output stream. The seqnos are non-negative and hr is guaranteed to be >= hd.
    Once variable-length encoding has been implemented, this method will probably get dropped as we can simply write the 2 longs individually.
    
    参数:
    hd - the highest delivered seqno. Guaranteed to be a positive number
    hr - the highest received seqno. Guaranteed to be a positive number. Greater than or equal to hd
    out - the output stream to write to
    
    抛出:
    
    java.io.IOException
  - readLongSequence
```
public static long[] readLongSequence(java.nio.ByteBuffer buf)
```
    Reads 2 compressed longs from buf.
    Once variable-length encoding has been implemented, this method will probably get dropped as we can simply read the 2 longs individually.
    
    参数:
    buf - the buffer to read from
    
    返回:
    an array of 2 longs (hd and hr)
  - readLongSequence
```
public static long[] readLongSequence(java.io.DataInput in)
                               throws java.io.IOException
```
    Reads 2 compressed longs from in. Reads 2 compressed longs from buf.
    Once variable-length encoding has been implemented, this method will probably get dropped as we can simply read the 2 longs individually.
    
    参数:
    in - the input stream to read from
    
    返回:
    an array of 2 longs (hd and hr)
    
    抛出:
    
    java.io.IOException
  - size
```
public static byte size(long hd,
        long hr)
```
  - makeLong
```
public static long makeLong(byte[] buf,
            int offset,
            int bytes_to_read)
```
  - makeInt
```
public static int makeInt(byte[] buf,
          int offset,
          int bytes_to_read)
```
  - writeFloat
```
public static void writeFloat(float num,
              java.nio.ByteBuffer buf)
```
    Writes a float to a ByteBuffer
    
    参数:
    num - the float to be written
    buf - the buffer
  - writeFloat
```
public static void writeFloat(float num,
              java.io.DataOutput out)
                       throws java.io.IOException
```
    Writes a float to an output stream
    
    参数:
    num - the float to be written
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readFloat
```
public static float readFloat(java.nio.ByteBuffer buf)
```
    Reads a a float from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the float read from the buffer
  - readFloat
```
public static float readFloat(java.io.DataInput in)
                       throws java.io.IOException
```
    Reads a a float from an input stream.
    
    参数:
    in - the input stream
    
    返回:
    the float read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(float num)
```
    Computes the size of a variable-length encoded float
    
    参数:
    num - the float
    
    返回:
    the number of bytes needed to variable-length encode num
  - writeDouble
```
public static void writeDouble(double num,
               java.nio.ByteBuffer buf)
```
    Writes a double to a ByteBuffer
    
    参数:
    num - the double to be written
    buf - the buffer
  - writeDouble
```
public static void writeDouble(double num,
               java.io.DataOutput out)
                        throws java.io.IOException
```
    Writes a double to an output stream
    
    参数:
    num - the double to be written
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readDouble
```
public static double readDouble(java.nio.ByteBuffer buf)
```
    Reads a double from a buffer.
    
    参数:
    buf - the buffer
    
    返回:
    the double read from the buffer
  - readDouble
```
public static double readDouble(java.io.DataInput in)
                         throws java.io.IOException
```
    Reads a double from an input stream
    
    参数:
    in - the input stream
    
    返回:
    the double read from the input stream
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(double num)
```
    Computes the size of a variable-length encoded double
    
    参数:
    num - the double
    
    返回:
    the number of bytes needed to variable-length encode num
  - writeString
```
public static void writeString(java.lang.String s,
               java.nio.ByteBuffer buf)
```
    Writes a string to buf. The length of the string is written first, followed by the chars (as single-byte values). Multi-byte values are truncated: only the lower byte of each multi-byte char is written, similar to DataOutput.writeChars(String).
    
    参数:
    s - the string
    buf - the buffer
  - writeString
```
public static void writeString(java.lang.String s,
               java.io.DataOutput out)
                        throws java.io.IOException
```
    Writes a string to buf. The length of the string is written first, followed by the chars (as single-byte values). Multi-byte values are truncated: only the lower byte of each multi-byte char is written, similar to DataOutput.writeChars(String).
    
    参数:
    s - the string
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readString
```
public static java.lang.String readString(java.nio.ByteBuffer buf)
```
    Reads a string from buf. The length is read first, followed by the chars. Each char is a single byte
    
    参数:
    buf - the buffer
    
    返回:
    the string read from buf
  - readString
```
public static java.lang.String readString(java.io.DataInput in)
                                   throws java.io.IOException
```
    Reads a string from buf. The length is read first, followed by the chars. Each char is a single byte
    
    参数:
    in - the input stream
    
    返回:
    the string read from buf
    
    抛出:
    
    java.io.IOException
  - sizeUTF
```
public static int sizeUTF(java.lang.String str)
```
    Measures the number of bytes required to encode a string, taking multibyte characters into account. Measures strings written by DataOutput.writeUTF(String).
    
    参数:
    str - the string
    
    返回:
    the number of bytes required for encoding str
  - writeAsciiString
```
public static void writeAsciiString(AsciiString s,
                    java.nio.ByteBuffer buf)
```
    Writes an AsciiString to buf. The length of the string is written first, followed by the chars (as single-byte values).
    
    参数:
    s - the string
    buf - the buffer
  - writeAsciiString
```
public static void writeAsciiString(AsciiString s,
                    java.io.DataOutput out)
                             throws java.io.IOException
```
    Writes an AsciiString to buf. The length of the string is written first, followed by the chars (as single-byte values).
    
    参数:
    s - the string
    out - the output stream
    
    抛出:
    
    java.io.IOException
  - readAsciiString
```
public static AsciiString readAsciiString(java.nio.ByteBuffer buf)
```
    Reads an AsciiString from buf. The length is read first, followed by the chars. Each char is a single byte
    
    参数:
    buf - the buffer
    
    返回:
    the string read from buf
  - readAsciiString
```
public static AsciiString readAsciiString(java.io.DataInput in)
                                   throws java.io.IOException
```
    Reads an AsciiString from buf. The length is read first, followed by the chars. Each char is a single byte
    
    参数:
    in - the input stream
    
    返回:
    the string read from buf
    
    抛出:
    
    java.io.IOException
  - size
```
public static int size(AsciiString str)
```
    Measures the number of bytes required to encode an AsciiSring.
    
    参数:
    str - the string
    
    返回:
    the number of bytes required for encoding str
  - encodeLength
```
protected static byte encodeLength(byte len1,
                byte len2)
```
    Encodes the number of bytes needed into a single byte. The first number is encoded in the first nibble (the first 4 bits), the second number in the second nibble
    
    参数:
    len1 - The number of bytes needed to store a long. Must be between 0 and 8
    len2 - The number of bytes needed to store a long. Must be between 0 and 8
    
    返回:
    The byte storing the 2 numbers len1 and len2
  - decodeLength
```
protected static byte[] decodeLength(byte len)
```
  - bytesRequiredFor
```
protected static byte bytesRequiredFor(long number)
```
  - bytesRequiredFor
```
protected static byte bytesRequiredFor(int number)
```
  - getByteAt
```
protected static byte getByteAt(long num,
             int index)
```

类 Bits

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

Bits

方法详细资料

writeChar

writeChar

readChar

readChar

size

writeShort

writeShort

readShort

readShort

readUnsignedShort

readUnsignedShort

size

makeShort

makeShort

writeInt

writeInt

readInt

readInt

size

writeLong

writeLong

readLong

readLong

size

writeLongSequence

writeLongSequence

readLongSequence

readLongSequence

size

makeLong

makeInt

writeFloat

writeFloat

readFloat

readFloat

size

writeDouble

writeDouble

readDouble

readDouble

size

writeString

writeString

readString

readString

sizeUTF

writeAsciiString

writeAsciiString

readAsciiString

readAsciiString

size

encodeLength

decodeLength

bytesRequiredFor

bytesRequiredFor

getByteAt