org.h2.mvstore.type

Class ObjectDataType

java.lang.Object

org.h2.mvstore.type.BasicDataType<java.lang.Object>

org.h2.mvstore.type.ObjectDataType

All Implemented Interfaces:

java.util.Comparator<java.lang.Object>, DataType<java.lang.Object>

public class ObjectDataType
extends BasicDataType<java.lang.Object>

A data type implementation for the most common data types, including serializable objects.

Constructor Summary

Constructors

Constructor and Description
ObjectDataType()

Method Summary

Modifier and Type	Method and Description
int	compare(java.lang.Object a, java.lang.Object b) Compare two keys.
static int	compareNotNull(byte[] data1, byte[] data2) Compare the contents of two byte arrays.
java.lang.Object[]	createStorage(int size) Create storage object of array type to hold values
static java.lang.Object	deserialize(byte[] data) De-serialize the byte array to an object.
int	getMemory(java.lang.Object obj) Calculates the amount of used memory in bytes.
java.lang.Object	read(java.nio.ByteBuffer buff) Read an object.
static byte[]	serialize(java.lang.Object obj) Serialize the object to a byte array.
void	write(WriteBuffer buff, java.lang.Object obj) Write an object.

Methods inherited from class org.h2.mvstore.type.BasicDataType

binarySearch, cast, equals, hashCode, isMemoryEstimationAllowed, read, write

Methods inherited from class java.lang.Object

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

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

ObjectDataType

public ObjectDataType()

Method Detail

createStorage

public java.lang.Object[] createStorage(int size)

Description copied from interface: DataType

Create storage object of array type to hold values

Parameters:

size - number of values to hold

Returns:

storage object

compare

public int compare(java.lang.Object a,
                   java.lang.Object b)

Description copied from interface: DataType

Compare two keys.

Specified by:

compare in interface java.util.Comparator<java.lang.Object>

Specified by:

compare in interface DataType<java.lang.Object>

Overrides:

compare in class BasicDataType<java.lang.Object>

Parameters:

a - the first key

b - the second key

Returns:

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

getMemory

public int getMemory(java.lang.Object obj)

Description copied from interface: DataType

Calculates the amount of used memory in bytes.

Specified by:

getMemory in interface DataType<java.lang.Object>

Specified by:

getMemory in class BasicDataType<java.lang.Object>

Parameters:

obj - the object

Returns:

the used memory

write

public void write(WriteBuffer buff,
                  java.lang.Object obj)

Description copied from interface: DataType

Write an object.

Specified by:

write in interface DataType<java.lang.Object>

Specified by:

write in class BasicDataType<java.lang.Object>

Parameters:

buff - the target buffer

obj - the value

read

public java.lang.Object read(java.nio.ByteBuffer buff)

Description copied from interface: DataType

Read an object.

Specified by:

read in interface DataType<java.lang.Object>

Specified by:

read in class BasicDataType<java.lang.Object>

Parameters:

buff - the source buffer

Returns:

the object

serialize

public static byte[] serialize(java.lang.Object obj)

Serialize the object to a byte array.

Parameters:

obj - the object to serialize

Returns:

the byte array

deserialize

public static java.lang.Object deserialize(byte[] data)

De-serialize the byte array to an object.

Parameters:

data - the byte array

Returns:

the object

compareNotNull

public static int compareNotNull(byte[] data1,
                                 byte[] data2)

Compare the contents of two byte arrays. If the content or length of the first array is smaller than the second array, -1 is returned. If the content or length of the second array is smaller than the first array, 1 is returned. If the contents and lengths are the same, 0 is returned.

This method interprets bytes as unsigned.

Parameters:

data1 - the first byte array (must not be null)

data2 - the second byte array (must not be null)

Returns:

the result of the comparison (-1, 1 or 0)