程序包 cn.taketoday.util.comparator

类 NullSafeComparator<T>

java.lang.Object

cn.taketoday.util.comparator.NullSafeComparator<T>

类型参数:

T - the type of objects that may be compared by this comparator

所有已实现的接口:

Comparator<T>

public class NullSafeComparator<T>
extends Object
implements Comparator<T>

A Comparator that will safely compare nulls to be lower or higher than other objects. Can decorate a given Comparator or work on Comparables.

从以下版本开始:

4.0

作者:

Keith Donald, Juergen Hoeller, Harry Yang

另请参阅:

• Comparable

字段概要

字段

修饰符和类型	字段	说明
private final Comparator<T>	nonNullComparator
static final NullSafeComparator	NULLS_HIGH	A shared default instance of this comparator, treating nulls higher than non-null objects.
static final NullSafeComparator	NULLS_LOW	A shared default instance of this comparator, treating nulls lower than non-null objects.
private final boolean	nullsLow

构造器概要

构造器

限定符	构造器	说明
private	NullSafeComparator(boolean nullsLow)	Create a NullSafeComparator that sorts null based on the provided flag, working on Comparables.
	NullSafeComparator(Comparator<T> comparator, boolean nullsLow)	Create a NullSafeComparator that sorts null based on the provided flag, decorating the given Comparator.

方法概要

修饰符和类型	方法	说明
int	compare(T left, T right)
boolean	equals(Object other)
int	hashCode()
String	toString()

从类继承的方法 java.lang.Object

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

从接口继承的方法 java.util.Comparator

reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

字段详细资料

NULLS_LOW

public static final NullSafeComparator NULLS_LOW

A shared default instance of this comparator, treating nulls lower than non-null objects.

另请参阅:

• Comparators.nullsLow()

NULLS_HIGH

public static final NullSafeComparator NULLS_HIGH

A shared default instance of this comparator, treating nulls higher than non-null objects.

另请参阅:

• Comparators.nullsHigh()

nonNullComparator

private final Comparator<T> nonNullComparator

nullsLow

private final boolean nullsLow

构造器详细资料

NullSafeComparator

private NullSafeComparator(boolean nullsLow)

Create a NullSafeComparator that sorts null based on the provided flag, working on Comparables.

When comparing two non-null objects, their Comparable implementation will be used: this means that non-null elements (that this Comparator will be applied to) need to implement Comparable.

As a convenience, you can use the default shared instances: NullSafeComparator.NULLS_LOW and NullSafeComparator.NULLS_HIGH.

参数:

nullsLow - whether to treat nulls lower or higher than non-null objects

另请参阅:

• Comparable
• NULLS_LOW
• NULLS_HIGH

NullSafeComparator

public NullSafeComparator(Comparator<T> comparator,
 boolean nullsLow)

Create a NullSafeComparator that sorts null based on the provided flag, decorating the given Comparator.

When comparing two non-null objects, the specified Comparator will be used. The given underlying Comparator must be able to handle the elements that this Comparator will be applied to.

参数:

comparator - the comparator to use when comparing two non-null objects

nullsLow - whether to treat nulls lower or higher than non-null objects

方法详细资料

compare

public int compare(@Nullable
 T left,
 @Nullable
 T right)

指定者:

compare 在接口中 Comparator<T>

equals

public boolean equals(@Nullable
 Object other)

指定者:

equals 在接口中 Comparator<T>

覆盖:

equals 在类中 Object

hashCode

public int hashCode()

覆盖:

hashCode 在类中 Object

toString

public String toString()

覆盖:

toString 在类中 Object