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java.lang.Objectorg.apache.commons.collections15.ComparatorUtils
public class ComparatorUtils
Provides convenient static utility methods for Comparator
objects.
comparators package. This class merely provides a
convenient central place if you have use for more than one class
in the comparators subpackage.
| Field Summary | |
|---|---|
static Comparator |
NATURAL_COMPARATOR
Comparator for natural sort order. |
| Constructor Summary | |
|---|---|
ComparatorUtils()
ComparatorUtils should not normally be instantiated. |
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| Method Summary | ||
|---|---|---|
static Comparator<Boolean> |
booleanComparator(boolean trueFirst)
Gets a Comparator that can sort Boolean objects. |
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static
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chainedComparator(Collection<T> 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. |
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static
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chainedComparator(Comparator<T>[] comparators)
Gets a comparator that compares using an array of Comparators, applied
in sequence until one returns not equal or the array is exhausted. |
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static
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chainedComparator(Comparator<T> comparator1,
Comparator<T> comparator2)
Gets a comparator that compares using two Comparators. |
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static
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max(T o1,
T o2,
Comparator<T> comparator)
Returns the larger of the given objects according to the given comparator, returning the second object if the comparator returns equal. |
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static
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min(T o1,
T o2,
Comparator<T> comparator)
Returns the smaller of the given objects according to the given comparator, returning the second object if the comparator returns equal. |
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static Comparator |
naturalComparator()
Gets a comparator that uses the natural order of the objects. |
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static
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nullHighComparator(Comparator<T> comparator)
Gets a Comparator that controls the comparison of null values. |
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static
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nullLowComparator(Comparator<T> comparator)
Gets a Comparator that controls the comparison of null values. |
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static
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reversedComparator(Comparator<T> comparator)
Gets a comparator that reverses the order of the given comparator. |
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static
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transformedComparator(Comparator<I> comparator,
Transformer<I,O> transformer)
Gets a Comparator that passes transformed objects to the given comparator. |
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| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static final Comparator NATURAL_COMPARATOR
ComparableComparator.getInstance()| Constructor Detail |
|---|
public ComparatorUtils()
| Method Detail |
|---|
public static Comparator naturalComparator()
public static <T> Comparator<T> chainedComparator(Comparator<T> comparator1,
Comparator<T> 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 null
ComparatorChain formed from the two comparators
NullPointerException - if either comparator is nullComparatorChainpublic static <T> Comparator<T> chainedComparator(Comparator<T>[] 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 nulls
ComparatorChain formed from the input comparators
NullPointerException - if comparators array is null or contains a nullComparatorChainpublic static <T> Comparator<T> chainedComparator(Collection<T> 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 nulls
ComparatorChain formed from the input comparators
NullPointerException - if comparators collection is null or contains a null
ClassCastException - if the comparators collection contains the wrong object typeComparatorChainpublic static <T> Comparator<T> reversedComparator(Comparator<T> comparator)
comparator - the comparator to reverse
ReverseComparatorpublic static Comparator<Boolean> booleanComparator(boolean trueFirst)
trueFirst - when true, sort
true Booleans before
false Booleans.
public static <T> Comparator<T> nullLowComparator(Comparator<T> 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 nulls
NullComparatorpublic static <T> Comparator<T> nullHighComparator(Comparator<T> 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 nulls
NullComparator
public static <I,O> Comparator<O> transformedComparator(Comparator<I> comparator,
Transformer<I,O> transformer)
comparator - the sort order to usetransformer - the transformer to use
TransformingComparator
public static <T> T min(T o1,
T o2,
Comparator<T> comparator)
o1 - the first object to compareo2 - the second object to comparecomparator - the sort order to use
public static <T> T max(T o1,
T o2,
Comparator<T> comparator)
o1 - the first object to compareo2 - the second object to comparecomparator - the sort order to use
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