net.openhft.lang.io

Interface RandomDataInput

All Superinterfaces:

AutoCloseable, BytesCommon, DataInput, ObjectInput, RandomAccess

All Known Subinterfaces:

Bytes

All Known Implementing Classes:

AbstractBytes, ByteBufferBytes, DirectBytes, MultiStoreBytes, NativeBytes

public interface RandomDataInput
extends ObjectInput, RandomAccess, BytesCommon

Author:

peter.lawrey

Method Summary

Methods

Modifier and Type	Method and Description
int	available()
void	close() Finishes the excerpt entry if not finished()
int	read() Reads a byte of data.
int	read(byte[] bytes) Reads into an array of bytes.
int	read(byte[] bytes, int off, int len) Reads into an array of bytes.
void	read(ByteBuffer bb) Copy bytes into a ByteBuffer to the minimum of the length remaining() in the ByteBuffer or the Excerpt.
boolean	readBoolean() Reads one input byte and returns true if that byte is nonzero, false if that byte is zero.
boolean	readBoolean(long offset) Reads one input byte and returns true if that byte is nonzero, false if that byte is zero.
byte	readByte() Reads and returns one input byte.
byte	readByte(long offset) Reads and returns one input byte.
char	readChar() Reads two input bytes and returns a char value.
char	readChar(long offset) Reads two input bytes and returns a char value.
double	readCompactDouble() Reads the first four bytes as readFloat().
int	readCompactInt() Reads two or six input bytes and returns an int value.
long	readCompactLong() Reads four or twelve input bytes and returns a long value.
short	readCompactShort() Reads one or three input bytes and returns a short value.
long	readCompactUnsignedInt() Reads two or six input bytes and returns an int value.
int	readCompactUnsignedShort() Reads one or three input bytes and returns a short value.
double	readDouble() Reads eight input bytes and returns a double value.
double	readDouble(long offset) Reads eight input bytes and returns a double value.
<E> E	readEnum(Class<E> eClass) Read a String with readUTFΔ which is converted to an enumerable type.
float	readFloat() Reads four input bytes and returns a float value.
float	readFloat(long offset) Reads four input bytes and returns a float value.
void	readFully(byte[] bytes) Reads some bytes from an input stream and stores them into the buffer array b.
void	readFully(byte[] bytes, int off, int len) Reads len bytes from an input stream.
int	readInt() Reads four input bytes and returns an int value.
int	readInt(long offset) Reads four input bytes and returns an int value.
int	readInt24() Reads three input bytes and returns a 24-bit int value.
int	readInt24(long offset) Reads three input bytes and returns a 24-bit int value.
long	readInt48() Reads six input bytes and returns a long value.
long	readInt48(long offset) Reads six input bytes and returns a long value.
String	readLine() Reads the next line of text from the input stream.
<E> void	readList(Collection<E> list, Class<E> eClass) Read a stop bit encoded length and populates this Collection after clear()ing it.
long	readLong() Reads eight input bytes and returns a long value.
long	readLong(long offset) Reads eight input bytes and returns a long value.
<K,V> Map<K,V>	readMap(Map<K,V> map, Class<K> kClass, Class<V> vClass) Read a stop bit encoded length and populates this Map after clear()ing it.
Object	readObject() Read and return an object.
<T> T	readObject(Class<T> tClass) Read and return an object.
void	readObject(Object object, int start, int end) Read the object from start to end bytes
short	readShort() Reads two input bytes and returns a short value.
short	readShort(long offset) Reads two input bytes and returns a short value.
long	readStopBit() Reads between one and ten bytes with are stop encoded with support for negative numbers
int	readUnsignedByte() Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
int	readUnsignedByte(long offset) Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
long	readUnsignedInt() Reads four input bytes and returns an int value.
long	readUnsignedInt(long offset) Reads four input bytes and returns an int value.
int	readUnsignedShort() Reads two input bytes and returns an int value in the range 0 through 65535.
int	readUnsignedShort(long offset) Reads two input bytes and returns an int value in the range 0 through 65535.
String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
String	readUTFΔ() The same as readUTF() except the length is stop bit encoded.
String	readUTFΔ(long offset) The same as readUTFΔ() except an offset and maximum length is given.
boolean	readUTFΔ(StringBuilder stringBuilder) The same as readUTFΔ() except the chars are copied to a truncated StringBuilder.
double	readVolatileDouble(long offset) This is the same as readDouble() except a read barrier is performed first.
float	readVolatileFloat(long offset) This is the same as readFloat() except a read barrier is performed first.
int	readVolatileInt() This is the same as readInt() except a read barrier is performed first.
int	readVolatileInt(long offset) This is the same as readInt() except a read barrier is performed first.
long	readVolatileLong() This is the same readLong() except a dread barrier is performed first Reads eight input bytes and returns a long value.
long	readVolatileLong(long offset) This is the same readLong() except a dread barrier is performed first Reads eight input bytes and returns a long value.
long	skip(long n) Skips n bytes of input.
int	skipBytes(int n) Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes.

Methods inherited from interface net.openhft.lang.io.BytesCommon

byteOrder, bytesMarshallerFactory, capacity, checkEndOfBuffer, finish, inputStream, isFinished, outputStream, position, position, remaining, reset, write

Method Detail

readFully

void readFully(@NotNull
             byte[] bytes)

Reads some bytes from an input stream and stores them into the buffer array b. The number of bytes read is equal to the length of b.

This method blocks until one of the following conditions occurs:

• b.length bytes of input data are available, in which case a normal return is made.

• End of file is detected, in which case an EOFException is thrown.

• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[0], the next one into b[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes of b have been updated with data from the input stream.

Specified by:

readFully in interface DataInput

Parameters:

bytes - the buffer into which the data is read.

readFully

void readFully(@NotNull
             byte[] bytes,
             int off,
             int len)

Reads len bytes from an input stream.

This method blocks until one of the following conditions occurs:

• len bytes of input data are available, in which case a normal return is made.

• End of file is detected, in which case an EOFException is thrown.

• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.

Specified by:

readFully in interface DataInput

Parameters:

bytes - the buffer into which the data is read.

off - an int specifying the offset into the data.

len - an int specifying the number of bytes to read.

skipBytes

int skipBytes(int n)

Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned.

Specified by:

skipBytes in interface DataInput

Parameters:

n - the number of bytes to be skipped.

Returns:

the number of bytes actually skipped.

readBoolean

boolean readBoolean()

Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface DataOutput.

Specified by:

readBoolean in interface DataInput

Returns:

the boolean value read.

readBoolean

boolean readBoolean(long offset)

Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface RandomDataOutput.

Parameters:

offset - to read byte translated into a boolean

Returns:

the boolean value read.

readByte

byte readByte()

Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface DataOutput.

Specified by:

readByte in interface DataInput

Returns:

the 8-bit value read.

readByte

byte readByte(long offset)

Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface RandomDataOutput.

Parameters:

offset - of byte to read.

Returns:

the 8-bit value read.

readUnsignedByte

int readUnsignedByte()

Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.

Specified by:

readUnsignedByte in interface DataInput

Returns:

the unsigned 8-bit value read.

readUnsignedByte

int readUnsignedByte(long offset)

Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface RandomDataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.

Parameters:

offset - of byte to read

Returns:

the unsigned 8-bit value read.

readShort

short readShort()

Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

(short)((a << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput.

Specified by:

readShort in interface DataInput

Returns:

the 16-bit value read.

readShort

short readShort(long offset)

Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

     (short)((a << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface RandomDataOutput.

Parameters:

offset - of short to read.

Returns:

the 16-bit value read.

readUnsignedShort

int readUnsignedShort()

Reads two input bytes and returns an int value in the range 0 through 65535. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

     (((a & 0xff) << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeUnsignedShort method of interface DataOutput if the argument to writeUnsignedShort was intended to be a value in the range 0 through 65535.

Specified by:

readUnsignedShort in interface DataInput

Returns:

the unsigned 16-bit value read.

readUnsignedShort

int readUnsignedShort(long offset)

Reads two input bytes and returns an int value in the range 0 through 65535. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

     (((a & 0xff) << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface RandomDataOutput if the argument to writeUnsignedShort was intended to be a value in the range 0 through 65535.

Parameters:

offset - of short to read.

Returns:

the unsigned 16-bit value read.

readCompactShort

short readCompactShort()

Reads one or three input bytes and returns a short value. Let a be the first byte read. This mapped as follows; Byte.MIN_VALUE => Short.MIN_VALUE, Byte.MAX_VALUE => Short.MAX_VALUE, Byte.MIN_VALUE+2 to Byte.MAX_VALUE-1 => same as short value, Byte.MIN_VALUE+1 => readShort().

This method is suitable for reading the bytes written by the writeCompactShort method of interface RandomDataOutput.

Returns:

the 16-bit value read.

readCompactUnsignedShort

int readCompactUnsignedShort()

Reads one or three input bytes and returns a short value. Let a be the first byte read. This mapped as follows; -1 => readUnsignedShort(), default => (a & 0xFF)

This method is suitable for reading the bytes written by the writeCompactUnsignedShort method of interface RandomDataOutput.

Returns:

the unsigned 16-bit value read.

readChar

char readChar()

Reads two input bytes and returns a char value. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

(char)((a << 8) | (b & 0xff))
 

This method is suitable for reading bytes written by the writeChar method of interface DataOutput.

Specified by:

readChar in interface DataInput

Returns:

the char value read.

readChar

char readChar(long offset)

Reads two input bytes and returns a char value. Let a be the first byte read and b be the second byte on big endian machines, and the opposite on little endian machines. The value returned is:

(char)((a << 8) | (b & 0xff))
 

This method is suitable for reading bytes written by the writeChar method of interface RandomDataOutput.

Parameters:

offset - of the char to read.

Returns:

the char value read.

readInt24

int readInt24()

Reads three input bytes and returns a 24-bit int value. Let a-c be the first through third bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 ((((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8))) >> 8
 

This method is suitable for reading bytes written by the writeInt24 method of interface RandomDataOutput.

Returns:

the int value read.

readInt24

int readInt24(long offset)

Reads three input bytes and returns a 24-bit int value. Let a-c be the first through third bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 ((((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8))) >> 8
 

This method is suitable for reading bytes written by the writeInt24 method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the int value read.

readInt

int readInt()

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeInt method of interface DataOutput.

Specified by:

readInt in interface DataInput

Returns:

the int value read.

readInt

int readInt(long offset)

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeInt method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the int value read.

readVolatileInt

int readVolatileInt()

This is the same as readInt() except a read barrier is performed first.

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeOrderedInt or writeVolatileInt method of interface RandomDataOutput.

Returns:

the int value read.

readVolatileInt

int readVolatileInt(long offset)

This is the same as readInt() except a read barrier is performed first.

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeOrderedInt or writeVolatileInt method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the int value read.

readUnsignedInt

long readUnsignedInt()

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 ((((long) a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d &
 0xff))
 

This method is suitable for reading bytes written by the writeUnsignedInt method of interface RandomDataOutput.

Returns:

the unsigned int value read.

readUnsignedInt

long readUnsignedInt(long offset)

Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 ((((long) a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d &
 0xff))
 

This method is suitable for reading bytes written by the writeUnsignedInt method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the unsigned int value read.

readCompactInt

int readCompactInt()

Reads two or six input bytes and returns an int value. Let a be the first short read with readShort(). This mapped as follows; Short.MIN_VALUE => Integer.MIN_VALUE, Short.MAX_VALUE => Integer.MAX_VALUE, Short.MIN_VALUE+2 to Short.MAX_VALUE-1 => same as short value, Short.MIN_VALUE+1 => readInt().

This method is suitable for reading the bytes written by the writeCompactInt method of interface RandomDataOutput.

Returns:

the 32-bit value read.

readCompactUnsignedInt

long readCompactUnsignedInt()

Reads two or six input bytes and returns an int value. Let a be the first short read with readShort(). This mapped as follows; -1 => readUnsignedInt(), default => (a & 0xFFFF)

This method is suitable for reading the bytes written by the writeCompactUnsignedInt method of interface RandomDataOutput.

Returns:

the unsigned 32-bit value read.

readLong

long readLong()

Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeLong method of interface DataOutput.

Specified by:

readLong in interface DataInput

Returns:

the long value read.

readLong

long readLong(long offset)

Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeLong method of interface RandomDataOutput.

Parameters:

offset - of the long to read

Returns:

the long value read.

readVolatileLong

long readVolatileLong()

This is the same readLong() except a dread barrier is performed first

Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeOrderedLong or writeVolatileLong method of interface RandomDataOutput.

Returns:

the long value read.

readVolatileLong

long readVolatileLong(long offset)

This is the same readLong() except a dread barrier is performed first

Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeOrderedLong or writeVolatileLong method of interface RandomDataOutput.

Parameters:

offset - of the long to read

Returns:

the long value read.

readInt48

long readInt48()

Reads six input bytes and returns a long value. Let a-f be the first through sixth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16)) >> 16
 

This method is suitable for reading bytes written by the writeInt48 method of interface RandomDataOutput.

Returns:

the long value read.

readInt48

long readInt48(long offset)

Reads six input bytes and returns a long value. Let a-f be the first through sixth bytes read on big endian machines, and the opposite on little endian machines. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16)) >> 16
 

This method is suitable for reading bytes written by the writeInt48 method of interface RandomDataOutput.

Parameters:

offset - of the long to read

Returns:

the long value read.

readCompactLong

long readCompactLong()

Reads four or twelve input bytes and returns a long value. Let a be the first int read with readInt(). This mapped as follows; Integer.MIN_VALUE => Long.MIN_VALUE, Integer.MAX_VALUE => Long.MAX_VALUE, Integer.MIN_VALUE+2 to Integer.MAX_VALUE-1 => same as short value, Integer.MIN_VALUE+1 => readLong().

This method is suitable for reading the bytes written by the writeCompactLong method of interface RandomDataOutput.

Returns:

the 64-bit value read.

readStopBit

long readStopBit()

Reads between one and ten bytes with are stop encoded with support for negative numbers

 long l = 0, b;
 int count = 0;
 while ((b = readByte()) < 0) {
     l |= (b & 0x7FL) << count;
     count += 7;
 }
 if (b == 0 && count > 0)
     return ~l;
 return l | (b << count);
 

Returns:

a stop bit encoded number as a long.

readFloat

float readFloat()

Reads four input bytes and returns a float value. It does this by first constructing an int value in exactly the manner of the readInt method, then converting this int value to a float in exactly the manner of the method Float.intBitsToFloat. This method is suitable for reading bytes written by the writeFloat method of interface DataOutput.

Specified by:

readFloat in interface DataInput

Returns:

the float value read.

readFloat

float readFloat(long offset)

Reads four input bytes and returns a float value. It does this by first constructing an int value in exactly the manner of the readInt method, then converting this int value to a float in exactly the manner of the method Float.intBitsToFloat. This method is suitable for reading bytes written by the writeFloat method of interface DataOutput.

Parameters:

offset - to read from

Returns:

the float value read.

readVolatileFloat

float readVolatileFloat(long offset)

This is the same as readFloat() except a read barrier is performed first.

Reads four input bytes and returns a float value.

This method is suitable for reading bytes written by the writeOrderedFloat method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the int value read.

readDouble

double readDouble()

Reads eight input bytes and returns a double value. It does this by first constructing a long value in exactly the manner of the readLong method, then converting this long value to a double in exactly the manner of the method Double.longBitsToDouble. This method is suitable for reading bytes written by the writeDouble method of interface DataOutput.

Specified by:

readDouble in interface DataInput

Returns:

the double value read.

readDouble

double readDouble(long offset)

Reads eight input bytes and returns a double value. It does this by first constructing a long value in exactly the manner of the readLong method, then converting this long value to a double in exactly the manner of the method Double.longBitsToDouble. This method is suitable for reading bytes written by the writeDouble method of interface DataOutput.

Parameters:

offset - to read from

Returns:

the double value read.

readCompactDouble

double readCompactDouble()

Reads the first four bytes as readFloat(). If this is Float.NaN, the next eight bytes are read as readDouble()

Returns:

the double value read.

readVolatileDouble

double readVolatileDouble(long offset)

This is the same as readDouble() except a read barrier is performed first.

Reads four input bytes and returns a float value.

This method is suitable for reading bytes written by the writeOrderedFloat method of interface RandomDataOutput.

Parameters:

offset - to read from

Returns:

the int value read.

readLine

@Nullable
String readLine()

Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a String. Note that because this method processes bytes, it does not support input of the full Unicode character set.

If end of file is encountered before even one byte can be read, then null is returned. Otherwise, each byte that is read is converted to type char by zero-extension. If the character '\n' is encountered, it is discarded and reading ceases. If the character '\r' is encountered, it is discarded and, if the following byte converts to the character '\n', then that is discarded also; reading then ceases. If end of file is encountered before either of the characters '\n' and '\r' is encountered, reading ceases. Once reading has ceased, a String is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than \u0100, that is, (char)256.

Specified by:

readLine in interface DataInput

Returns:

the next line of text from the input stream, or null if the end of file is encountered before a byte can be read.

readUTF

@NotNull
String readUTF()

Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the readUnsignedShort method . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.

If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.

If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

(char)(((a& 0x1F) << 6) | (b & 0x3F))
 

If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

 (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
 

If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.

If end of file is encountered at any time during this entire process, then an EOFException is thrown.

After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.

The writeUTF method of interface DataOutput may be used to write data that is suitable for reading by this method.

Specified by:

readUTF in interface DataInput

Returns:

a Unicode string.

Throws:

IllegalStateException - if the bytes do not represent a valid modified UTF-8 encoding of a string.

readUTFΔ

@Nullable
String readUTFΔ()

The same as readUTF() except the length is stop bit encoded. This saves one byte for strings shorter than 128 chars. null values are also supported

Returns:

a Unicode string or null if writeUTFΔ(null) was called

readUTFΔ

@Nullable
String readUTFΔ(long offset)
                throws IllegalStateException

The same as readUTFΔ() except an offset and maximum length is given.

Parameters:

offset - to read from

Returns:

a Unicode string or null if writeUTFΔ(null) was called

Throws:

IllegalStateException - if the length to be read is out of range.

readUTFΔ

boolean readUTFΔ(@NotNull
               StringBuilder stringBuilder)

The same as readUTFΔ() except the chars are copied to a truncated StringBuilder.

Returns:

true if there was a String, or false if it was null

read

void read(@NotNull
        ByteBuffer bb)

Copy bytes into a ByteBuffer to the minimum of the length remaining() in the ByteBuffer or the Excerpt.

Parameters:

bb - to copy into

readEnum

@Nullable
<E> E readEnum(@NotNull
                      Class<E> eClass)

Read a String with readUTFΔ which is converted to an enumerable type. i.e. where there is a one to one mapping between an object and it's toString().

This is suitable to read an object written using writeEnum() in the RandomDataOutput interface

Parameters:

eClass - to decode the String as

Returns:

the decoded value. null with be return if null was written.

readList

<E> void readList(@NotNull
                Collection<E> list,
                @NotNull
                Class<E> eClass)

Read a stop bit encoded length and populates this Collection after clear()ing it.

This is suitable to reading a list written using writeList() in the RandomDataOutput interface

Parameters:

list - to populate

readMap

<K,V> Map<K,V> readMap(@NotNull
                     Map<K,V> map,
                     @NotNull
                     Class<K> kClass,
                     @NotNull
                     Class<V> vClass)

Read a stop bit encoded length and populates this Map after clear()ing it.

This is suitable to reading a list written using writeMap() in the RandomDataOutput interface

Parameters:

map - to populate

Returns:

the map

readObject

@Nullable
Object readObject()
                  throws IllegalStateException

Read and return an object. The class that implements this interface defines where the object is "read" from.

Specified by:

readObject in interface ObjectInput

Returns:

the object read from the stream

Throws:

IllegalStateException - the class of a serialized object cannot be found or any of the usual Input/Output related exceptions occur.

readObject

@Nullable
<T> T readObject(Class<T> tClass)
             throws IllegalStateException

Read and return an object. The class that implements this interface defines where the object is "read" from.

Returns:

the object read from the stream

Throws:

IllegalStateException - the class of a serialized object cannot be found or any of the usual Input/Output related exceptions occur.

ClassCastException - The class cannot be cast or converted to the type given.

read

int read()

Reads a byte of data. This method will block if no input is available.

Specified by:

read in interface ObjectInput

Returns:

the byte read, or -1 if the end of the stream is reached.

read

int read(@NotNull
       byte[] bytes)

Reads into an array of bytes. This method will block until some input is available.

Specified by:

read in interface ObjectInput

Parameters:

bytes - the buffer into which the data is read

Returns:

the actual number of bytes read, -1 is returned when the end of the stream is reached.

read

int read(@NotNull
       byte[] bytes,
       int off,
       int len)

Reads into an array of bytes. This method will block until some input is available.

Specified by:

read in interface ObjectInput

Parameters:

bytes - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of bytes read

Returns:

the actual number of bytes read, -1 is returned when the end of the stream is reached.

readObject

void readObject(Object object,
              int start,
              int end)

Read the object from start to end bytes

Parameters:

object - to read into

start - byte inclusive

end - byte exclusive

skip

long skip(long n)

Skips n bytes of input.

Specified by:

skip in interface ObjectInput

Parameters:

n - the number of bytes to be skipped

Returns:

the actual number of bytes skipped.

available

int available()

Specified by:

available in interface ObjectInput

Returns:

remaining() or Integer.MAX_VALUE if larger.

close

void close()

Finishes the excerpt entry if not finished()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ObjectInput