Package org.apache.commons.collections4.bag

Class PredicatedSortedBag<E>

  • Type Parameters:
    E - the type of elements in this bag
    All Implemented Interfaces:
    java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, Bag<E>, SortedBag<E>
    public class PredicatedSortedBag<E>
extends PredicatedBag<E>
implements SortedBag<E>
    Decorates another SortedBag to validate that additions match a specified predicate.

    This bag exists to provide validation for the decorated bag. It is normally created to decorate an empty bag. If an object cannot be added to the bag, an IllegalArgumentException is thrown.

    One usage would be to ensure that no null entries are added to the bag. 

     SortedBag bag = PredicatedSortedBag.predicatedSortedBag(new TreeBag(), NotNullPredicate.INSTANCE);

    This class is Serializable from Commons Collections 3.1.

    Since:
    3.0
    See Also:
    Serialized Form

    • Method Detail

      • predicatedSortedBag

        public static <E> PredicatedSortedBag<E> predicatedSortedBag​(SortedBag<E> bag,
                                                             Predicate<? super E> predicate)
        Factory method to create a predicated (validating) bag.

        If there are any elements already in the bag being decorated, they are validated.

        Type Parameters:
        E - the type of the elements in the bag
        Parameters:
        bag - the bag to decorate, must not be null
        predicate - the predicate to use for validation, must not be null
        Returns:
        a new predicated SortedBag
        Throws:
        java.lang.NullPointerException - if bag or predicate is null
        java.lang.IllegalArgumentException - if the bag contains invalid elements
        Since:
        4.0

      • first

        public E first()
        Description copied from interface: SortedBag
        Returns the first (lowest) member.
        Specified by:
        first in interface SortedBag<E>
        Returns:
        the first element in the sorted bag

      • last

        public E last()
        Description copied from interface: SortedBag
        Returns the last (highest) member.
        Specified by:
        last in interface SortedBag<E>
        Returns:
        the last element in the sorted bag

      • comparator

        public java.util.Comparator<? super E> comparator()
        Description copied from interface: SortedBag
        Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
        Specified by:
        comparator in interface SortedBag<E>
        Returns:
        the comparator in use, or null if natural ordering