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.
|
| Constructor and Description |
|---|
ComparatorUtils()
ComparatorUtils should not normally be instantiated.
|
| Modifier and Type | Method and Description |
|---|---|
static Comparator |
booleanComparator(boolean trueFirst)
Gets a Comparator that can sort Boolean objects.
|
static Comparator |
chainedComparator(Collection 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 Comparator |
chainedComparator(Comparator[] 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 Comparator |
chainedComparator(Comparator comparator1,
Comparator comparator2)
Gets a comparator that compares using two
Comparators. |
static Object |
max(Object o1,
Object o2,
Comparator comparator)
Returns the larger of the given objects according to the given
comparator, returning the second object if the comparator
returns equal.
|
static Object |
min(Object o1,
Object o2,
Comparator comparator)
Returns the smaller of the given objects according to the given
comparator, returning the second object if the comparator
returns equal.
|
static Comparator |
naturalComparator()
Gets a comparator that uses the natural order of the objects.
|
static Comparator |
nullHighComparator(Comparator comparator)
Gets a Comparator that controls the comparison of
null values. |
static Comparator |
nullLowComparator(Comparator comparator)
Gets a Comparator that controls the comparison of
null values. |
static Comparator |
reversedComparator(Comparator comparator)
Gets a comparator that reverses the order of the given comparator.
|
static Comparator |
transformedComparator(Comparator comparator,
Transformer transformer)
Gets a Comparator that passes transformed objects to the given comparator.
|
public static final Comparator NATURAL_COMPARATOR
ComparableComparator.getInstance()public ComparatorUtils()
public static Comparator naturalComparator()
public static Comparator chainedComparator(Comparator comparator1, Comparator comparator2)
Comparators.
The second comparator is used if the first comparator returns equal.
comparator1 - the first comparator to use, not nullcomparator2 - the first comparator to use, not nullComparatorChain formed from the two comparatorsNullPointerException - if either comparator is nullComparatorChainpublic static Comparator chainedComparator(Comparator[] comparators)
Comparators, applied
in sequence until one returns not equal or the array is exhausted.comparators - 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 Comparator chainedComparator(Collection comparators)
Comparators,
applied in (default iterator) sequence until one returns not equal or the
collection is exhausted.comparators - 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 Comparator reversedComparator(Comparator comparator)
comparator - the comparator to reverseReverseComparatorpublic static Comparator 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 Comparator nullLowComparator(Comparator 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.
comparator - the comparator that wants to allow nullsNullComparatorpublic static Comparator nullHighComparator(Comparator 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.
comparator - the comparator that wants to allow nullsNullComparatorpublic static Comparator transformedComparator(Comparator comparator, Transformer transformer)
Objects passed to the returned comparator will first be transformed by the given transformer before they are compared by the given comparator.
comparator - the sort order to usetransformer - the transformer to useTransformingComparatorpublic static Object min(Object o1, Object o2, Comparator comparator)
o1 - the first object to compareo2 - the second object to comparecomparator - the sort order to usepublic static Object max(Object o1, Object o2, Comparator comparator)
o1 - the first object to compareo2 - the second object to comparecomparator - the sort order to useCopyright © 2001–2015 The Apache Software Foundation. All rights reserved.