net.sergeych.recordsfile

Class StructureDescriptor

java.lang.Object

net.sergeych.recordsfile.StructureDescriptor

public class StructureDescriptor
extends java.lang.Object

Byte structures packer/unpacker. Uses network byte order (big endian). Allows to pack/unpack integers, byte[] arrasy and string into fixed-size byte sequences. The main idea is to convert integers or longs to/from bytes fields using unsigned notation and network order. Can also store byte arrays and strings.

Constructor Summary

Constructors

Constructor and Description
StructureDescriptor()

Method Summary

Modifier and Type	Method and Description
StructureDescriptor	addBinaryField(java.lang.String name, int length) Add byte[] field.
StructureDescriptor	addByteField(java.lang.String name)
StructureDescriptor	addField(java.lang.String name, int sizeInBytes) Add ingeter field to the structure.
StructureDescriptor	addField(java.lang.String name, int sizeInBytes, java.lang.Class itemClass) Add field specifying both size in bytes and class of the object to unpack to.
StructureDescriptor	addIntField(java.lang.String name)
StructureDescriptor	addLongField(java.lang.String name)
StructureDescriptor	addShortField(java.lang.String name)
StructureDescriptor	addStringField(java.lang.String name, int fieldSize) Add string field to be packed usgin system default encoding (utf-8 mainly) into a fixed-size bytes slot.
int	getSize() Full structure size.
byte[]	pack(Binder data) Pack structure into binary data with given values
byte[]	pack(Binder data, boolean ignoreNonFields) Pack structure using given values, optionally ignore keys that are not included in the structure.
void	packTo(byte[] bytes, int fromOffset, Binder data, boolean ignoreNonFields) Pack structure with given data into existing binary array from a specified offset
Binder	unpack(byte[] res) unpack packed binary data
Binder	unpack(byte[] data, int fromOffset) Unpack packed binary data staring from a given offset

Methods inherited from class java.lang.Object

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

Constructor Detail

StructureDescriptor

public StructureDescriptor()

Method Detail

getSize

public int getSize()

Full structure size.

Returns:

unpack

public Binder unpack(byte[] res)

unpack packed binary data

Parameters:

res -

Returns:

unpack

public Binder unpack(byte[] data,
                     int fromOffset)

Unpack packed binary data staring from a given offset

Parameters:

data -

fromOffset - w

Returns:

Binder with map of unpacked fields

addField

public StructureDescriptor addField(java.lang.String name,
                                    int sizeInBytes)

Add ingeter field to the structure.

Parameters:

name -

sizeInBytes - in network order, should be between 1 and 8 inclusive

Returns:

this

addField

public StructureDescriptor addField(java.lang.String name,
                                    int sizeInBytes,
                                    java.lang.Class itemClass)

Add field specifying both size in bytes and class of the object to unpack to.

Parameters:

name -

sizeInBytes - from 1 to 8 inclusive

itemClass - item unpack to

Returns:

this

pack

public byte[] pack(Binder data)

Pack structure into binary data with given values

Parameters:

data - map of values. If any key in the map does not belong to the structure. throws IllegalArgumentException

Returns:

packed structure

pack

public byte[] pack(Binder data,
                   boolean ignoreNonFields)

Pack structure using given values, optionally ignore keys that are not included in the structure.

Parameters:

data - map of values to pack

ignoreNonFields - if true ignores any keys not listed in the structure, owtherwise throws IllegalArgumentException.

Returns:

packed structure

packTo

public void packTo(byte[] bytes,
                   int fromOffset,
                   Binder data,
                   boolean ignoreNonFields)

Pack structure with given data into existing binary array from a specified offset

Parameters:

bytes - binary array where to put data

fromOffset - put packed data starting from this offset

data - map of values to pack

ignoreNonFields - if true ignores any keys not listed in the structure, owtherwise throws IllegalArgumentException.

addByteField

public StructureDescriptor addByteField(java.lang.String name)

addShortField

public StructureDescriptor addShortField(java.lang.String name)

addIntField

public StructureDescriptor addIntField(java.lang.String name)

addLongField

public StructureDescriptor addLongField(java.lang.String name)

addBinaryField

public StructureDescriptor addBinaryField(java.lang.String name,
                                          int length)

Add byte[] field.

Parameters:

name -

length - in bytes, any positive value.

Returns:

this

addStringField

public StructureDescriptor addStringField(java.lang.String name,
                                          int fieldSize)

Add string field to be packed usgin system default encoding (utf-8 mainly) into a fixed-size bytes slot. Maximum size in bytes is either (fieldSize - 1) bytes (fieldSize <= 256, or fieldSize - 2 bytes otherwise except for extremely long fields, longer than 64Kb, in which case it be fieldSize - 3. Note that string length in characters could be any depending on the characters used.

Parameters:

name -

fieldSize -

Returns: