Package com.yahoo.collections

Class CollectionUtil

  • public class CollectionUtil
extends java.lang.Object
    Utilities for java collections
    Since:
    5.1.8
    Author:
    Tony Vaagenes, gjoranv

    • Constructor Summary

      Constructors 
      Constructor Description
      CollectionUtil()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static boolean equalContentsIgnoreOrder​(java.util.Collection<?> c1, java.util.Collection<?> c2)
      Returns true if the contents of the two given collections are equal, ignoring order.
      static <T> java.util.Collection<T> filter​(java.util.Collection<?> collection, java.lang.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​(java.util.Collection<T> collection)
      Returns the first element in a collection according to iteration order.
      static <T> java.util.Optional<T> firstMatching​(T[] array, java.util.function.Predicate<? super T> predicate)  
      static java.lang.String mkString​(java.util.Collection<?> collection, java.lang.String sep)
      Returns a String containing the string representation of all elements from the given collection, separated by the separator string.
      static <T> java.lang.String mkString​(java.util.Collection<T> collection, java.lang.String start, java.lang.String sep, java.lang.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> java.util.Set<T> symmetricDifference​(java.util.Collection<? extends T> c1, java.util.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 Detail

      • CollectionUtil

        public CollectionUtil()

    • Method Detail

      • mkString

        public static java.lang.String mkString​(java.util.Collection<?> collection,
                                        java.lang.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> java.lang.String mkString​(java.util.Collection<T> collection,
                                            java.lang.String start,
                                            java.lang.String sep,
                                            java.lang.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​(java.util.Collection<?> c1,
                                               java.util.Collection<?> c2)
        Returns true if the contents of the two given collections are equal, ignoring order.

      • symmetricDifference

        public static <T> java.util.Set<T> symmetricDifference​(java.util.Collection<? extends T> c1,
                                                       java.util.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> java.util.Collection<T> filter​(java.util.Collection<?> collection,
                                                 java.lang.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​(java.util.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> java.util.Optional<T> firstMatching​(T[] array,
                                                      java.util.function.Predicate<? super T> predicate)