org.h2.mode

枚举 DefaultNullOrdering

java.lang.Object

java.lang.Enum<DefaultNullOrdering>

org.h2.mode.DefaultNullOrdering

所有已实现的接口:

Serializable, Comparable<DefaultNullOrdering>

public enum DefaultNullOrdering
extends Enum<DefaultNullOrdering>

Default ordering of NULL values.

枚举常量概要

枚举常量

枚举常量和说明
FIRST NULL values are sorted before other values, no matter if ascending or descending order is used.
HIGH NULL values are considered as larger than other values during sorting.
LAST NULL values are sorted after other values, no matter if ascending or descending order is used.
LOW NULL values are considered as smaller than other values during sorting.

方法概要

限定符和类型	方法和说明
int	addExplicitNullOrdering(int sortType) Returns a sort type bit mask with SortOrder.NULLS_FIRST or SortOrder.NULLS_LAST explicitly set
int	compareNull(boolean aNull, int sortType) Compare two expressions where one of them is NULL.
static DefaultNullOrdering	valueOf(int ordinal) Returns default ordering of NULL values for the specified ordinal number.
static DefaultNullOrdering	valueOf(String name) 返回带有指定名称的该类型的枚举常量。
static DefaultNullOrdering[]	values() 按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。

从类继承的方法 java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

从类继承的方法 java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

枚举常量详细资料

LOW

public static final DefaultNullOrdering LOW

NULL values are considered as smaller than other values during sorting.

HIGH

public static final DefaultNullOrdering HIGH

NULL values are considered as larger than other values during sorting.

FIRST

public static final DefaultNullOrdering FIRST

NULL values are sorted before other values, no matter if ascending or descending order is used.

LAST

public static final DefaultNullOrdering LAST

NULL values are sorted after other values, no matter if ascending or descending order is used.

方法详细资料

values

public static DefaultNullOrdering[] values()

按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。该方法可用于迭代 常量, 如下所示:

for (DefaultNullOrdering c : DefaultNullOrdering.values())
    System.out.println(c);

返回:

按照声明该枚举类型的常量的顺序返回的包含这些常量的数组

valueOf

public static DefaultNullOrdering valueOf(String name)

返回带有指定名称的该类型的枚举常量。 字符串必须与用于声明该类型的枚举常量的 标识符完全匹配。(不允许有多余 的空格字符。)

参数:

name - 要返回的枚举常量的名称。

返回:

返回带有指定名称的枚举常量

抛出:

IllegalArgumentException - 如果该枚举类型没有带有指定名称的常量

NullPointerException - 如果参数为空值

valueOf

public static DefaultNullOrdering valueOf(int ordinal)

Returns default ordering of NULL values for the specified ordinal number.

参数:

ordinal - ordinal number

返回:

default ordering of NULL values for the specified ordinal number

另请参阅:

Enum.ordinal()

addExplicitNullOrdering

public int addExplicitNullOrdering(int sortType)

Returns a sort type bit mask with SortOrder.NULLS_FIRST or SortOrder.NULLS_LAST explicitly set

参数:

sortType - sort type bit mask

返回:

bit mask with SortOrder.NULLS_FIRST or SortOrder.NULLS_LAST explicitly set

compareNull

public int compareNull(boolean aNull,
                       int sortType)

Compare two expressions where one of them is NULL.

参数:

aNull - whether the first expression is null

sortType - the sort bit mask to use

返回:

the result of the comparison (-1 meaning the first expression should appear before the second, 0 if they are equal)