org.h2.mvstore.type

接口 DataType

所有已知实现类:

ObjectDataType, SpatialDataType, StringDataType, TransactionStore.ArrayType, TransactionStore.VersionedValueType, ValueDataType

public interface DataType

A data type.

方法概要

限定符和类型	方法和说明
int	compare(Object a, Object b) Compare two keys.
int	getMemory(Object obj) Estimate the used memory in bytes.
Object	read(ByteBuffer buff) Read an object.
void	read(ByteBuffer buff, Object[] obj, int len, boolean key) Read a list of objects.
void	write(WriteBuffer buff, Object obj) Write an object.
void	write(WriteBuffer buff, Object[] obj, int len, boolean key) Write a list of objects.

方法详细资料

compare

int compare(Object a,
            Object b)

Compare two keys.

参数:

a - the first key

b - the second key

返回:

-1 if the first key is smaller, 1 if larger, and 0 if equal

抛出:

UnsupportedOperationException - if the type is not orderable

getMemory

int getMemory(Object obj)

Estimate the used memory in bytes.

参数:

obj - the object

返回:

the used memory

write

void write(WriteBuffer buff,
           Object obj)

Write an object.

参数:

buff - the target buffer

obj - the value

write

void write(WriteBuffer buff,
           Object[] obj,
           int len,
           boolean key)

Write a list of objects.

参数:

buff - the target buffer

obj - the objects

len - the number of objects to write

key - whether the objects are keys

read

Object read(ByteBuffer buff)

Read an object.

参数:

buff - the source buffer

返回:

the object

read

void read(ByteBuffer buff,
          Object[] obj,
          int len,
          boolean key)

Read a list of objects.

参数:

buff - the target buffer

obj - the objects

len - the number of objects to read

key - whether the objects are keys