org.h2.mvstore.type

接口 DataType<T>

所有超级接口:

Comparator<T>

所有已知实现类:

BasicDataType, ByteArrayDataType, LobStorageMap.BlobMeta.Type, LobStorageMap.BlobReference.Type, LongDataType, MetaType, NullValueDataType, ObjectDataType, RowDataType, SpatialDataType, StringDataType, ValueDataType, VersionedValueType

public interface DataType<T>
extends Comparator<T>

A data type.

方法概要

限定符和类型	方法和说明
int	binarySearch(T key, Object storage, int size, int initialGuess) Perform binary search for the key within the storage
int	compare(T a, T b) Compare two keys.
T[]	createStorage(int size) Create storage object of array type to hold values
int	getMemory(T obj) Calculates the amount of used memory in bytes.
boolean	isMemoryEstimationAllowed() Whether memory estimation based on previously seen values is allowed/desirable
T	read(ByteBuffer buff) Read an object.
void	read(ByteBuffer buff, Object storage, int len) Read a list of objects.
void	write(WriteBuffer buff, Object storage, int len) Write a list of objects.
void	write(WriteBuffer buff, T obj) Write an object.

从接口继承的方法 java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

方法详细资料

compare

int compare(T a,
            T b)

Compare two keys.

指定者:

compare 在接口中 Comparator<T>

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

binarySearch

int binarySearch(T key,
                 Object storage,
                 int size,
                 int initialGuess)

Perform binary search for the key within the storage

参数:

key - to search for

storage - to search within (an array of type T)

size - number of data items in the storage

initialGuess - for key position

返回:

index of the key , if found, - index of the insertion point, if not

getMemory

int getMemory(T obj)

Calculates the amount of used memory in bytes.

参数:

obj - the object

返回:

the used memory

isMemoryEstimationAllowed

boolean isMemoryEstimationAllowed()

Whether memory estimation based on previously seen values is allowed/desirable

返回:

true if memory estimation is allowed

write

void write(WriteBuffer buff,
           T obj)

Write an object.

参数:

buff - the target buffer

obj - the value

write

void write(WriteBuffer buff,
           Object storage,
           int len)

Write a list of objects.

参数:

buff - the target buffer

storage - the objects

len - the number of objects to write

read

T read(ByteBuffer buff)

Read an object.

参数:

buff - the source buffer

返回:

the object

read

void read(ByteBuffer buff,
          Object storage,
          int len)

Read a list of objects.

参数:

buff - the target buffer

storage - the objects

len - the number of objects to read

createStorage

T[] createStorage(int size)

Create storage object of array type to hold values

参数:

size - number of values to hold

返回:

storage object