Package com.yahoo.collections

Class CollectionUtil

java.lang.Object

com.yahoo.collections.CollectionUtil

public class CollectionUtil
extends Object

Utilities for java collections

Author:

Tony Vaagenes, gjoranv

Constructor Summary

Constructors

Constructor	Description
CollectionUtil()

Method Summary

Modifier and Type	Method	Description
static boolean	equalContentsIgnoreOrder(Collection<?> c1, Collection<?> c2)	Returns true if the contents of the two given collections are equal, ignoring order.
static <T> Collection<T>	filter(Collection<?> collection, Class<T> lowerBound)	Returns the subset of elements from the given collection that can be cast to the reference type, defined by the given Class object.
static <T> T	first(Collection<T> collection)	Returns the first element in a collection according to iteration order.
static <T> Optional<T>	firstMatching(T[] array, Predicate<? super T> predicate)
static String	mkString(Collection<?> collection, String sep)	Returns a String containing the string representation of all elements from the given collection, separated by the separator string.
static <T> String	mkString(Collection<T> collection, String start, String sep, String end)	Returns a String containing the string representation of all elements from the given collection, using a start string, separator strings, and an end string.
static <T> Set<T>	symmetricDifference(Collection<? extends T> c1, Collection<? extends T> c2)	Returns the symmetric difference between two collections, i.e.

Methods inherited from class java.lang.Object

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

Constructor Details

CollectionUtil

public CollectionUtil()

Method Details

mkString

public static String mkString(Collection<?> collection,
 String sep)

Returns a String containing the string representation of all elements from the given collection, separated by the separator string.

Parameters:

collection - The collection

sep - The separator string

Returns:

A string: elem(0) + sep + ... + elem(N)

mkString

public static <T> String mkString(Collection<T> collection,
 String start,
 String sep,
 String end)

Returns a String containing the string representation of all elements from the given collection, using a start string, separator strings, and an end string.

Type Parameters:

T - The element type

Parameters:

collection - The collection

start - The start string

sep - The separator string

end - The end string

Returns:

A string: start + elem(0) + sep + ... + elem(N) + end

equalContentsIgnoreOrder

public static boolean equalContentsIgnoreOrder(Collection<?> c1,
 Collection<?> c2)

Returns true if the contents of the two given collections are equal, ignoring order.

symmetricDifference

public static <T> Set<T> symmetricDifference(Collection<? extends T> c1,
 Collection<? extends T> c2)

Returns the symmetric difference between two collections, i.e. the set of elements that occur in exactly one of the collections.

filter

public static <T> Collection<T> filter(Collection<?> collection,
 Class<T> lowerBound)

Returns the subset of elements from the given collection that can be cast to the reference type, defined by the given Class object.

first

public static <T> T first(Collection<T> collection)

Returns the first element in a collection according to iteration order. Returns null if the collection is empty.

firstMatching

public static <T> Optional<T> firstMatching(T[] array,
 Predicate<? super T> predicate)