public class ComparatorUtils extends Object
Comparator
objects.
Most of the functionality in this class can also be found in the
comparators package. This class merely provides a
convenient central place if you have use for more than one class
in the comparators subpackage.
| Modifier and Type | Field and Description |
|---|---|
static Comparator |
NATURAL_COMPARATOR
Comparator for natural sort order.
|
| Modifier and Type | Method and Description |
|---|---|
static Comparator<Boolean> |
booleanComparator(boolean trueFirst)
Gets a Comparator that can sort Boolean objects.
|
static <E extends Comparable<? super E>> |
chainedComparator(Collection<Comparator<E>> comparators)
Gets a comparator that compares using a collection of
Comparators,
applied in (default iterator) sequence until one returns not equal or the
collection is exhausted. |
static <E extends Comparable<? super E>> |
chainedComparator(Comparator<E>... comparators)
Gets a comparator that compares using an array of
Comparators, applied
in sequence until one returns not equal or the array is exhausted. |
static <E> E |
max(E o1,
E o2,
Comparator<E> comparator)
Returns the larger of the given objects according to the given
comparator, returning the second object if the comparator
returns equal.
|
static <E> E |
min(E o1,
E o2,
Comparator<E> comparator)
Returns the smaller of the given objects according to the given
comparator, returning the second object if the comparator
returns equal.
|
static <E extends Comparable<? super E>> |
naturalComparator()
Gets a comparator that uses the natural order of the objects.
|
static <E> Comparator<E> |
nullHighComparator(Comparator<E> comparator)
Gets a Comparator that controls the comparison of
null values. |
static <E> Comparator<E> |
nullLowComparator(Comparator<E> comparator)
Gets a Comparator that controls the comparison of
null values. |
static <E> Comparator<E> |
reversedComparator(Comparator<E> comparator)
Gets a comparator that reverses the order of the given comparator.
|
static <I,O> Comparator<I> |
transformedComparator(Comparator<O> comparator,
Transformer<? super I,? extends O> transformer)
Gets a Comparator that passes transformed objects to the given comparator.
|
public static final Comparator NATURAL_COMPARATOR
public static <E extends Comparable<? super E>> Comparator<E> naturalComparator()
E - the object type to comparepublic static <E extends Comparable<? super E>> Comparator<E> chainedComparator(Comparator<E>... comparators)
Comparators, applied
in sequence until one returns not equal or the array is exhausted.E - the object type to comparecomparators - the comparators to use, not null or empty or containing nullsComparatorChain formed from the input comparatorsNullPointerException - if comparators array is null or contains a nullComparatorChainpublic static <E extends Comparable<? super E>> Comparator<E> chainedComparator(Collection<Comparator<E>> comparators)
Comparators,
applied in (default iterator) sequence until one returns not equal or the
collection is exhausted.E - the object type to comparecomparators - the comparators to use, not null or empty or containing nullsComparatorChain formed from the input comparatorsNullPointerException - if comparators collection is null or contains a nullClassCastException - if the comparators collection contains the wrong object typeComparatorChainpublic static <E> Comparator<E> reversedComparator(Comparator<E> comparator)
E - the object type to comparecomparator - the comparator to reverseReverseComparatorpublic static Comparator<Boolean> booleanComparator(boolean trueFirst)
The parameter specifies whether true or false is sorted first.
The comparator throws NullPointerException if a null value is compared.
public static <E> Comparator<E> nullLowComparator(Comparator<E> comparator)
null values.
The returned comparator will consider a null value to be less than any nonnull value, and equal to any other null value. Two nonnull values will be evaluated with the given comparator.
E - the object type to comparecomparator - the comparator that wants to allow nullsNullComparatorpublic static <E> Comparator<E> nullHighComparator(Comparator<E> comparator)
null values.
The returned comparator will consider a null value to be greater than any nonnull value, and equal to any other null value. Two nonnull values will be evaluated with the given comparator.
E - the object type to comparecomparator - the comparator that wants to allow nullsNullComparatorpublic static <I,O> Comparator<I> transformedComparator(Comparator<O> comparator, Transformer<? super I,? extends O> transformer)
Objects passed to the returned comparator will first be transformed by the given transformer before they are compared by the given comparator.
I - the input object type of the transformed comparatorO - the object type of the decorated comparatorcomparator - the sort order to usetransformer - the transformer to useTransformingComparatorpublic static <E> E min(E o1,
E o2,
Comparator<E> comparator)
E - the object type to compareo1 - the first object to compareo2 - the second object to comparecomparator - the sort order to usepublic static <E> E max(E o1,
E o2,
Comparator<E> comparator)
E - the object type to compareo1 - the first object to compareo2 - the second object to comparecomparator - the sort order to useCopyright © 2001–2013 The Apache Software Foundation. All rights reserved.