org.apache.commons.collections4.bag

Class SynchronizedBag<E>

  • All Implemented Interfaces:
    Serializable, Iterable<E>, Collection<E>, Bag<E>
    Direct Known Subclasses:
    SynchronizedSortedBag 

    public class SynchronizedBag<E>
extends SynchronizedCollection<E>
implements Bag<E>
    Decorates another Bag to synchronize its behaviour for a multi-threaded environment.

    Methods are synchronized, then forwarded to the decorated bag. Iterators must be separately synchronized around the loop.

    This class is Serializable from Commons Collections 3.1.

    Since:
    3.0
    See Also:
    Serialized Form

    • Constructor Detail

      • SynchronizedBag

        protected SynchronizedBag(Bag<E> bag)
        Constructor that wraps (not copies).
        Parameters:
        bag - the bag to decorate, must not be null
        Throws:
        NullPointerException - if bag is null

      • SynchronizedBag

        protected SynchronizedBag(Bag<E> bag,
                          Object lock)
        Constructor that wraps (not copies).
        Parameters:
        bag - the bag to decorate, must not be null
        lock - the lock to use, must not be null
        Throws:
        NullPointerException - if bag or lock is null

    • Method Detail

      • synchronizedBag

        public static <E> SynchronizedBag<E> synchronizedBag(Bag<E> bag)
        Factory method to create a synchronized bag.
        Type Parameters:
        E - the type of the elements in the bag
        Parameters:
        bag - the bag to decorate, must not be null
        Returns:
        a new synchronized Bag
        Throws:
        NullPointerException - if bag is null
        Since:
        4.0

      • getBag

        protected Bag<E> getBag()
        Gets the bag being decorated.
        Returns:
        the decorated bag

      • equals

        public boolean equals(Object object)

      • hashCode

        public int hashCode()

      • add

        public boolean add(E object,
                   int count)
        Description copied from interface: Bag
        Adds nCopies copies of the specified object to the Bag.

        If the object is already in the Bag.uniqueSet() then increment its count as reported by Bag.getCount(Object). Otherwise add it to the Bag.uniqueSet() and report its count as nCopies.

        Specified by:
        add in interface  Bag<E>
        Parameters:
        object - the object to add
        count - the number of copies to add
        Returns:
        true if the object was not already in the uniqueSet

      • remove

        public boolean remove(Object object,
                      int count)
        Description copied from interface: Bag
        Removes nCopies copies of the specified object from the Bag.

        If the number of copies to remove is greater than the actual number of copies in the Bag, no error is thrown.

        Specified by:
        remove in interface  Bag<E>
        Parameters:
        object - the object to remove
        count - the number of copies to remove
        Returns:
        true if this call changed the collection

      • uniqueSet

        public Set<E> uniqueSet()
        Description copied from interface: Bag
        Returns a Set of unique elements in the Bag.

        Uniqueness constraints are the same as those in Set.

        Specified by:
        uniqueSet in interface  Bag<E>
        Returns:
        the Set of unique Bag elements

      • getCount

        public int getCount(Object object)
        Description copied from interface: Bag
        Returns the number of occurrences (cardinality) of the given object currently in the bag. If the object does not exist in the bag, return 0.
        Specified by:
        getCount in interface  Bag<E>
        Parameters:
        object - the object to search for
        Returns:
        the number of occurrences of the object, zero if not found