NullSafeComparator (Spring Framework API 2.1) - Spring Framework 2.1.0 API 文档英文版

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org.springframework.util.comparator
Class NullSafeComparator

java.lang.Object
  org.springframework.util.comparator.NullSafeComparator

All Implemented Interfaces:: Comparator

public class NullSafeComparator
extends Object
implements Comparator
extends Object
implements Comparator

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

Since:: 1.2.2
Author:: Keith Donald, Juergen Hoeller
See Also:: Comparable

Field Summary

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

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

Constructor Summary

NullSafeComparator(Comparator comparator, boolean nullsLow)
          Create a NullSafeComparator that sorts null based on the provided flag, decorating the given Comparator.

Method Summary

int compare(Object o1, Object o2)


boolean equals(Object obj)


int hashCode()


String toString()


Methods inherited from class java.lang.Object

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

Field Summary
`static NullSafeComparator`	`NULLS_HIGH` A shared default instance of this comparator, treating nulls higher than non-null objects.
`static NullSafeComparator`	`NULLS_LOW` A shared default instance of this comparator, treating nulls lower than non-null objects.

Constructor Summary
`NullSafeComparator(Comparator comparator, boolean nullsLow)` Create a NullSafeComparator that sorts `null` based on the provided flag, decorating the given Comparator.

Method Summary
`int`	`compare(Object o1, Object o2)`
`boolean`	`equals(Object obj)`
`int`	`hashCode()`
`String`	`toString()`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Field Detail

NULLS_LOW

public static final NullSafeComparator NULLS_LOW

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

NULLS_HIGH

public static final NullSafeComparator NULLS_HIGH

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

Constructor Detail