org.agrona.io

Class DirectBufferDataInput

java.lang.Object

org.agrona.io.DirectBufferDataInput

All Implemented Interfaces:

DataInput

public class DirectBufferDataInput
extends Object
implements DataInput

A data input implementation that reads from a DirectBuffer. It adheres to the contract defined in DataInput description including throwing checked exception on end of file. It adds few more methods to read strings without allocations.

Note about byte ordering: by default, this class conforms to DataInput contract and uses ByteOrder.BIG_ENDIAN byte order which allows it to read data produced by JDK DataOutput implementations. Agrona buffers use ByteOrder.LITTLE_ENDIAN (unless overridden). Use byteOrder(ByteOrder) method to switch between JDK and Agrona compatibility.

Constructor Summary

Constructors

Constructor and Description
DirectBufferDataInput(DirectBuffer buffer) Wrap given DirectBuffer.
DirectBufferDataInput(DirectBuffer buffer, int offset, int length) Wrap given DirectBuffer.

Method Summary

Modifier and Type	Method and Description
void	byteOrder(ByteOrder byteOrder) Sets the byte order.
boolean	readBoolean()
byte	readByte()
char	readChar()
double	readDouble()
float	readFloat()
void	readFully(byte[] destination)
void	readFully(byte[] destination, int destinationOffset, int length)
int	readInt()
String	readLine()
int	readLine(Appendable appendable) Reads the next line of text from the input stream.
long	readLong()
short	readShort()
String	readStringAscii() Reads in a string that has been encoded using ASCII format by MutableDirectBuffer.putStringAscii(int, CharSequence).
int	readStringAscii(Appendable appendable) Get a String from bytes encoded in ASCII format that is length prefixed and append to an Appendable.
String	readStringUTF8() Reads in a string that has been encoded using UTF-8 format by MutableDirectBuffer.putStringUtf8(int, String).
int	readUnsignedByte()
int	readUnsignedShort()
String	readUTF()
int	remaining() Return the number of bytes remaining in the buffer.
int	skipBytes(int n)
void	wrap(DirectBuffer buffer) Wrap given DirectBuffer.
void	wrap(DirectBuffer buffer, int offset, int length) Wrap given DirectBuffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DirectBufferDataInput

public DirectBufferDataInput(DirectBuffer buffer)

Wrap given DirectBuffer.

Parameters:

buffer - to wrap.

DirectBufferDataInput

public DirectBufferDataInput(DirectBuffer buffer,
                             int offset,
                             int length)

Wrap given DirectBuffer.

Parameters:

buffer - to wrap.

offset - into the buffer.

length - in bytes.

Method Detail

wrap

public void wrap(DirectBuffer buffer)

Wrap given DirectBuffer.

Parameters:

buffer - to wrap.

wrap

public void wrap(DirectBuffer buffer,
                 int offset,
                 int length)

Wrap given DirectBuffer.

Parameters:

buffer - to wrap.

offset - into the buffer.

length - in bytes.

byteOrder

public void byteOrder(ByteOrder byteOrder)

Sets the byte order. By default, this class conforms to DataInput contract and uses ByteOrder.BIG_ENDIAN which allows it to read data produced by JDK DataOutput implementations. Agrona buffers use ByteOrder.LITTLE_ENDIAN (unless overridden). Use this method to switch compatibility between these two worlds.

Parameters:

byteOrder - of the underlying buffer.

remaining

public int remaining()

Return the number of bytes remaining in the buffer.

Returns:

the number of bytes remaining.

readFully

public void readFully(byte[] destination)
               throws EOFException

Specified by:

readFully in interface DataInput

Throws:

EOFException

readFully

public void readFully(byte[] destination,
                      int destinationOffset,
                      int length)
               throws EOFException

Specified by:

readFully in interface DataInput

Throws:

EOFException

skipBytes

public int skipBytes(int n)

Specified by:

skipBytes in interface DataInput

readBoolean

public boolean readBoolean()
                    throws EOFException

Specified by:

readBoolean in interface DataInput

Throws:

EOFException

readByte

public byte readByte()
              throws EOFException

Specified by:

readByte in interface DataInput

Throws:

EOFException

readUnsignedByte

public int readUnsignedByte()
                     throws EOFException

Specified by:

readUnsignedByte in interface DataInput

Throws:

EOFException

readShort

public short readShort()
                throws EOFException

Specified by:

readShort in interface DataInput

Throws:

EOFException

readUnsignedShort

public int readUnsignedShort()
                      throws EOFException

Specified by:

readUnsignedShort in interface DataInput

Throws:

EOFException

readChar

public char readChar()
              throws EOFException

Specified by:

readChar in interface DataInput

Throws:

EOFException

readInt

public int readInt()
            throws EOFException

Specified by:

readInt in interface DataInput

Throws:

EOFException

readLong

public long readLong()
              throws EOFException

Specified by:

readLong in interface DataInput

Throws:

EOFException

readFloat

public float readFloat()
                throws EOFException

Specified by:

readFloat in interface DataInput

Throws:

EOFException

readDouble

public double readDouble()
                  throws EOFException

Specified by:

readDouble in interface DataInput

Throws:

EOFException

readLine

public String readLine()
                throws IOException

Specified by:

readLine in interface DataInput

Throws:

IOException

readLine

public int readLine(Appendable appendable)
             throws IOException

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; Adheres to the contract of DataInput.readLine().

Parameters:

appendable - to append the chars to.

Returns:

number of bytes the stream advanced while reading the line (including line terminators).

Throws:

IOException - propagated from Appendable.append(char).

readUTF

public String readUTF()
               throws EOFException

Specified by:

readUTF in interface DataInput

Throws:

EOFException

readStringUTF8

public String readStringUTF8()

Reads in a string that has been encoded using UTF-8 format by MutableDirectBuffer.putStringUtf8(int, String).

This is a thin wrapper over DirectBuffer.getStringUtf8(int, ByteOrder). Honours byte order set by byteOrder(ByteOrder).

Returns:

the String as represented by the ASCII encoded bytes.

readStringAscii

public String readStringAscii()

Reads in a string that has been encoded using ASCII format by MutableDirectBuffer.putStringAscii(int, CharSequence).

This is a thin wrapper over DirectBuffer.getStringAscii(int, ByteOrder). Honours byte order set by byteOrder(ByteOrder)

Returns:

the String as represented by the ASCII encoded bytes.

readStringAscii

public int readStringAscii(Appendable appendable)

Get a String from bytes encoded in ASCII format that is length prefixed and append to an Appendable. This is a thin wrapper over DirectBuffer.getStringAscii(int, Appendable, ByteOrder). Honours byte order set by byteOrder(ByteOrder).

Parameters:

appendable - to append the chars to.

Returns:

the number of bytes copied.