Apache Commons Collections 4.4 · org.apache.commons.collections4.comparators.NullComparator

Modifier and Type	Field and Description
private final Comparator<? super E>	nonNullComparator The comparator to use when comparing two non-`null` objects.
private final boolean	nullsAreHigh Specifies whether a `null` are compared as higher than non-`null` objects.
private static final long	serialVersionUID Serialization version.

Constructor Summary

Access	Constructor and Description
public	NullComparator() Construct an instance that sorts `null` higher than any non-`null` object it is compared with.
public	NullComparator(final Comparator<? super E> the comparator to use when comparing two non-`null` objects. This argument cannot be `null` nonNullComparator) Construct an instance that sorts `null` higher than any non-`null` object it is compared with.
public	NullComparator(final boolean a `true` value indicates that `null` should be compared as higher than a non-`null` object. A `false` value indicates that `null` should be compared as lower than a non-`null` object. nullsAreHigh) Construct an instance that sorts `null` higher or lower than any non-`null` object it is compared with.
public	NullComparator(final Comparator<? super E> the comparator to use when comparing two non-`null` objects. This argument cannot be `null` nonNullComparator, final boolean a `true` value indicates that `null` should be compared as higher than a non-`null` object. A `false` value indicates that `null` should be compared as lower than a non-`null` object. nullsAreHigh) Construct an instance that sorts `null` higher or lower than any non-`null` object it is compared with.

Method Summary

Modifier and Type	Method and Description
public int	Returns: `-1` if `o1` is "lower" than (less than, before, etc.) `o2`; `1` if `o1` is "higher" than (greater than, after, etc.) `o2`; or `0` if `o1` and `o2` are equal. compare(final E the first object to compare o1, final E the object to compare it to. o2) Implements java.util.Comparator.compare. Perform a comparison between two objects.
public boolean	Returns: `true` if the specified object is a NullComparator with equivalent `null` comparison behavior (i.e. `null` high or low) and with equivalent underlying non-`null` object comparators. equals(final Object the object to compare this comparator with. obj) Overrides java.lang.Object.equals. Implements java.util.Comparator.equals. Determines whether the specified object represents a comparator that is equal to this comparator.
public int	Returns: a hash code for this comparator. hashCode() Overrides java.lang.Object.hashCode. Implement a hash code for this comparator that is consistent with `equals(Object)`.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll toString wait wait wait

Field Detail

nonNullComparator	back to summary
private final Comparator<? super E> nonNullComparator The comparator to use when comparing two non-`null` objects.

nullsAreHigh	back to summary
private final boolean nullsAreHigh Specifies whether a `null` are compared as higher than non-`null` objects.

serialVersionUID	back to summary
private static final long serialVersionUID Serialization version.

Constructor Detail

NullComparator	back to summary
public NullComparator() Construct an instance that sorts `null` higher than any non-`null` object it is compared with. When comparing two non-`null` objects, the `ComparableComparator` is used.

NullComparator back to summary

NullComparator	back to summary
public NullComparator(final Comparator<? super E> nonNullComparator) Construct an instance that sorts `null` higher than any non-`null` object it is compared with. When comparing two non-`null` objects, the specified `Comparator` is used. Parameters nonNullComparator:Comparator<? super E> the comparator to use when comparing two non-`null` objects. This argument cannot be `null` Exceptions NullPointerException: if `nonNullComparator` is `null`

public NullComparator(final Comparator<? super E> nonNullComparator)

Construct an instance that sorts null higher than any non-null object it is compared with. When comparing two non-null objects, the specified Comparator is used.

Parameters

nonNullComparator:Comparator<? super E>: the comparator to use when comparing two non-null objects. This argument cannot be null

Exceptions

NullPointerException:: if nonNullComparator is null

NullComparator back to summary

NullComparator	back to summary
public NullComparator(final boolean nullsAreHigh) Construct an instance that sorts `null` higher or lower than any non-`null` object it is compared with. When comparing two non-`null` objects, the `ComparableComparator` is used. Parameters nullsAreHigh:boolean a `true` value indicates that `null` should be compared as higher than a non-`null` object. A `false` value indicates that `null` should be compared as lower than a non-`null` object.

public NullComparator(final boolean nullsAreHigh)

Construct an instance that sorts null higher or lower than any non-null object it is compared with. When comparing two non-null objects, the ComparableComparator is used.

Parameters

nullsAreHigh:boolean: a true value indicates that null should be compared as higher than a non-null object. A false value indicates that null should be compared as lower than a non-null object.

NullComparator back to summary

NullComparator	back to summary
public NullComparator(final Comparator<? super E> nonNullComparator, final boolean nullsAreHigh) Construct an instance that sorts `null` higher or lower than any non-`null` object it is compared with. When comparing two non-`null` objects, the specified `Comparator` is used. Parameters nonNullComparator:Comparator<? super E> the comparator to use when comparing two non-`null` objects. This argument cannot be `null` nullsAreHigh:boolean a `true` value indicates that `null` should be compared as higher than a non-`null` object. A `false` value indicates that `null` should be compared as lower than a non-`null` object. Exceptions NullPointerException: if `nonNullComparator` is `null`

public NullComparator(final Comparator<? super E> nonNullComparator, final boolean nullsAreHigh)

Construct an instance that sorts null higher or lower than any non-null object it is compared with. When comparing two non-null objects, the specified Comparator is used.

Parameters

nonNullComparator:Comparator<? super E>: the comparator to use when comparing two non-null objects. This argument cannot be null
nullsAreHigh:boolean: a true value indicates that null should be compared as higher than a non-null object. A false value indicates that null should be compared as lower than a non-null object.

Exceptions

NullPointerException:: if nonNullComparator is null

Method Detail

compare back to summary

compare	back to summary
public int compare(final E o1, final E o2) Implements java.util.Comparator.compare. Perform a comparison between two objects. If both objects are `null`, a `0` value is returned. If one object is `null` and the other is not, the result is determined on whether the Comparator was constructed to have nulls as higher or lower than other objects. If neither object is `null`, an underlying comparator specified in the constructor (or the default) is used to compare the non-`null` objects. Parameters o1:E the first object to compare o2:E the object to compare it to. Returns:int `-1` if `o1` is "lower" than (less than, before, etc.) `o2`; `1` if `o1` is "higher" than (greater than, after, etc.) `o2`; or `0` if `o1` and `o2` are equal. Annotations @Override

public int compare(final E o1, final E o2)

Implements java.util.Comparator.compare.

Perform a comparison between two objects. If both objects are null, a 0 value is returned. If one object is null and the other is not, the result is determined on whether the Comparator was constructed to have nulls as higher or lower than other objects. If neither object is null, an underlying comparator specified in the constructor (or the default) is used to compare the non-null objects.

Parameters

o1:E: the first object to compare
o2:E: the object to compare it to.

Returns:int

-1 if o1 is "lower" than (less than, before, etc.) o2; 1 if o1 is "higher" than (greater than, after, etc.) o2; or 0 if o1 and o2 are equal.

Annotations

@Override

equals back to summary

equals	back to summary
public boolean equals(final Object obj) Overrides java.lang.Object.equals. Implements java.util.Comparator.equals. Determines whether the specified object represents a comparator that is equal to this comparator. Parameters obj:Object the object to compare this comparator with. Returns:boolean `true` if the specified object is a NullComparator with equivalent `null` comparison behavior (i.e. `null` high or low) and with equivalent underlying non-`null` object comparators. Annotations @Override

public boolean equals(final Object obj)

Overrides java.lang.Object.equals.

Implements java.util.Comparator.equals.

Determines whether the specified object represents a comparator that is equal to this comparator.

Parameters

obj:Object: the object to compare this comparator with.

Returns:boolean

true if the specified object is a NullComparator with equivalent null comparison behavior (i.e. null high or low) and with equivalent underlying non-null object comparators.

Annotations

@Override

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Implement a hash code for this comparator that is consistent with `equals(Object)`. Returns:int a hash code for this comparator. Annotations @Override

public int hashCode()

Overrides java.lang.Object.hashCode.

Implement a hash code for this comparator that is consistent with equals(Object).

Returns:int

a hash code for this comparator.

Annotations

@Override

public Class NullComparator<E>

Field Summary

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Field Detail

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