org.h2.mvstore.type

Class BasicDataType<T>

java.lang.Object

org.h2.mvstore.type.BasicDataType<T>

All Implemented Interfaces:

java.util.Comparator<T>, DataType<T>

Direct Known Subclasses:

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

public abstract class BasicDataType<T>
extends java.lang.Object
implements DataType<T>

The base class for data type implementations.

Constructor Summary

Constructors

Constructor and Description
BasicDataType()

Method Summary

Modifier and Type	Method and Description
int	binarySearch(T key, java.lang.Object storageObj, int size, int initialGuess) Perform binary search for the key within the storage
protected T[]	cast(java.lang.Object storage) Cast the storage object to an array of type T.
int	compare(T a, T b) Compare two keys.
boolean	equals(java.lang.Object obj)
abstract int	getMemory(T obj) Calculates the amount of used memory in bytes.
int	hashCode()
boolean	isMemoryEstimationAllowed() Whether memory estimation based on previously seen values is allowed/desirable
abstract T	read(java.nio.ByteBuffer buff) Read an object.
void	read(java.nio.ByteBuffer buff, java.lang.Object storage, int len) Read a list of objects.
void	write(WriteBuffer buff, java.lang.Object storage, int len) Write a list of objects.
abstract void	write(WriteBuffer buff, T obj) Write an object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.mvstore.type.DataType

createStorage

Methods inherited from interface java.util.Comparator

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

Constructor Detail

BasicDataType

public BasicDataType()

Method Detail

getMemory

public abstract int getMemory(T obj)

Description copied from interface: DataType

Calculates the amount of used memory in bytes.

Specified by:

getMemory in interface DataType<T>

Parameters:

obj - the object

Returns:

the used memory

write

public abstract void write(WriteBuffer buff,
                           T obj)

Description copied from interface: DataType

Write an object.

Specified by:

write in interface DataType<T>

Parameters:

buff - the target buffer

obj - the value

read

public abstract T read(java.nio.ByteBuffer buff)

Description copied from interface: DataType

Read an object.

Specified by:

read in interface DataType<T>

Parameters:

buff - the source buffer

Returns:

the object

compare

public int compare(T a,
                   T b)

Description copied from interface: DataType

Compare two keys.

Specified by:

compare in interface java.util.Comparator<T>

Specified by:

compare in interface DataType<T>

Parameters:

a - the first key

b - the second key

Returns:

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

isMemoryEstimationAllowed

public boolean isMemoryEstimationAllowed()

Description copied from interface: DataType

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

Specified by:

isMemoryEstimationAllowed in interface DataType<T>

Returns:

true if memory estimation is allowed

binarySearch

public int binarySearch(T key,
                        java.lang.Object storageObj,
                        int size,
                        int initialGuess)

Description copied from interface: DataType

Perform binary search for the key within the storage

Specified by:

binarySearch in interface DataType<T>

Parameters:

key - to search for

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

size - number of data items in the storage

initialGuess - for key position

Returns:

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

write

public void write(WriteBuffer buff,
                  java.lang.Object storage,
                  int len)

Description copied from interface: DataType

Write a list of objects.

Specified by:

write in interface DataType<T>

Parameters:

buff - the target buffer

storage - the objects

len - the number of objects to write

read

public void read(java.nio.ByteBuffer buff,
                 java.lang.Object storage,
                 int len)

Description copied from interface: DataType

Read a list of objects.

Specified by:

read in interface DataType<T>

Parameters:

buff - the target buffer

storage - the objects

len - the number of objects to read

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Comparator<T>

Overrides:

equals in class java.lang.Object

cast

protected final T[] cast(java.lang.Object storage)

Cast the storage object to an array of type T.

Parameters:

storage - the storage object

Returns:

the array