org.sellcom.core.collection

Class MoreCollections

java.lang.Object

org.sellcom.core.collection.MoreCollections

public class MoreCollections
extends Object

Operations with collections.

Since:

1.0

See Also:

Collections

Method Summary

Modifier and Type	Method and Description
static NavigableSet<String>	caseIgnoringSet() Returns an empty case-ignoring NavigableSet.
static NavigableSet<String>	caseIgnoringSet(Collection<String> strings) Returns a case-ignoring NavigableSet containing the given strings.
static <T> Map<T,Integer>	countFrequencies(Collection<T> collection) Returns an immutable map containing the distinct values of the given collection as keys and their frequency as values.
static <E> Collection<E>	emptyToNull(Collection<E> collection) Returns the given collection if it is non-empty, null otherwise.
static <E> boolean	isNullOrEmpty(Collection<E> collection) Checks whether the given collection is null or empty.
static <E> List<E>	nullToEmpty(List<E> set) Returns the given list if it is non-empty, empty list otherwise.
static <E> NavigableSet<E>	nullToEmpty(NavigableSet<E> navigableSet) Returns the given navigable set if it is non-empty, empty navigable set otherwise.
static <E> Set<E>	nullToEmpty(Set<E> set) Returns the given set if it is non-empty, empty set otherwise.
static <K,V extends Comparable<V>> Map<K,V>	sortByValues(Map<K,V> map) Returns an immutable map containing the mappings in the given map sorted by their values.
static <K,V> Map<K,V>	sortByValues(Map<K,V> map, Comparator<V> comparator) Returns an immutable map containing the mappings in the given map sorted by their values.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

countFrequencies

public static <T> Map<T,Integer> countFrequencies(Collection<T> collection)

Returns an immutable map containing the distinct values of the given collection as keys and their frequency as values.

Throws:

IllegalArgumentException - if collection is null

Since:

1.0

caseIgnoringSet

public static NavigableSet<String> caseIgnoringSet()

Returns an empty case-ignoring NavigableSet.

Since:

1.0

caseIgnoringSet

public static NavigableSet<String> caseIgnoringSet(Collection<String> strings)

Returns a case-ignoring NavigableSet containing the given strings.

Throws:

IllegalArgumentException - if strings are null

Since:

1.0

emptyToNull

public static <E> Collection<E> emptyToNull(Collection<E> collection)

Returns the given collection if it is non-empty, null otherwise.

Since:

1.0

isNullOrEmpty

public static <E> boolean isNullOrEmpty(Collection<E> collection)

Checks whether the given collection is null or empty.

Since:

1.0

nullToEmpty

public static <E> List<E> nullToEmpty(List<E> set)

Returns the given list if it is non-empty, empty list otherwise.

Since:

1.0

nullToEmpty

public static <E> NavigableSet<E> nullToEmpty(NavigableSet<E> navigableSet)

Returns the given navigable set if it is non-empty, empty navigable set otherwise.

Since:

1.0

nullToEmpty

public static <E> Set<E> nullToEmpty(Set<E> set)

Returns the given set if it is non-empty, empty set otherwise.

Since:

1.0

sortByValues

public static <K,V extends Comparable<V>> Map<K,V> sortByValues(Map<K,V> map)

Returns an immutable map containing the mappings in the given map sorted by their values.

Throws:

IllegalArgumentException - if map is null

Since:

1.0

sortByValues

public static <K,V> Map<K,V> sortByValues(Map<K,V> map,
                                          Comparator<V> comparator)

Returns an immutable map containing the mappings in the given map sorted by their values.

Throws:

IllegalArgumentException - if map is null

IllegalArgumentException - if comparator is null

Since:

1.0