Package org.apache.commons.collections

Class BagUtils

  • @Deprecated(since="2021-04-30")
public class BagUtils
extends java.lang.Object
    Deprecated.
    Commons Collections 3 is in maintenance mode. Commons Collections 4 should be used instead.
    Provides utility methods and decorators for Bag and SortedBag instances.
    Since:
    Commons Collections 2.1

    • Field Detail

      • EMPTY_BAG

        public static final Bag EMPTY_BAG
        Deprecated.
        An empty unmodifiable bag.

      • EMPTY_SORTED_BAG

        public static final Bag EMPTY_SORTED_BAG
        Deprecated.
        An empty unmodifiable sorted bag.

    • Constructor Detail

      • BagUtils

        public BagUtils()
        Deprecated.
        Instantiation of BagUtils is not intended or required. However, some tools require an instance to operate.

    • Method Detail

      • synchronizedBag

        public static Bag synchronizedBag​(Bag bag)
        Deprecated.
        Returns a synchronized (thread-safe) bag backed by the given bag. In order to guarantee serial access, it is critical that all access to the backing bag is accomplished through the returned bag.

        It is imperative that the user manually synchronize on the returned bag when iterating over it: 

         Bag bag = BagUtils.synchronizedBag(new HashBag());
 ...
 synchronized(bag) {
     Iterator i = bag.iterator(); // Must be in synchronized block
     while (i.hasNext())
         foo(i.next());
     }
 }
        Failure to follow this advice may result in non-deterministic behavior.
        Parameters:
        bag - the bag to synchronize, must not be null
        Returns:
        a synchronized bag backed by that bag
        Throws:
        java.lang.IllegalArgumentException - if the Bag is null

      • unmodifiableBag

        public static Bag unmodifiableBag​(Bag bag)
        Deprecated.
        Returns an unmodifiable view of the given bag. Any modification attempts to the returned bag will raise an UnsupportedOperationException.
        Parameters:
        bag - the bag whose unmodifiable view is to be returned, must not be null
        Returns:
        an unmodifiable view of that bag
        Throws:
        java.lang.IllegalArgumentException - if the Bag is null

      • predicatedBag

        public static Bag predicatedBag​(Bag bag,
                                Predicate predicate)
        Deprecated.
        Returns a predicated (validating) bag backed by the given bag.

        Only objects that pass the test in the given predicate can be added to the bag. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original bag after invoking this method, as it is a backdoor for adding invalid objects.

        Parameters:
        bag - the bag to predicate, must not be null
        predicate - the predicate for the bag, must not be null
        Returns:
        a predicated bag backed by the given bag
        Throws:
        java.lang.IllegalArgumentException - if the Bag or Predicate is null

      • typedBag

        public static Bag typedBag​(Bag bag,
                           java.lang.Class type)
        Deprecated.
        Returns a typed bag backed by the given bag.

        Only objects of the specified type can be added to the bag.

        Parameters:
        bag - the bag to limit to a specific type, must not be null
        type - the type of objects which may be added to the bag
        Returns:
        a typed bag backed by the specified bag

      • transformedBag

        public static Bag transformedBag​(Bag bag,
                                 Transformer transformer)
        Deprecated.
        Returns a transformed bag backed by the given bag.

        Each object is passed through the transformer as it is added to the Bag. It is important not to use the original bag after invoking this method, as it is a backdoor for adding untransformed objects.

        Parameters:
        bag - the bag to predicate, must not be null
        transformer - the transformer for the bag, must not be null
        Returns:
        a transformed bag backed by the given bag
        Throws:
        java.lang.IllegalArgumentException - if the Bag or Transformer is null

      • synchronizedSortedBag

        public static SortedBag synchronizedSortedBag​(SortedBag bag)
        Deprecated.
        Returns a synchronized (thread-safe) sorted bag backed by the given sorted bag. In order to guarantee serial access, it is critical that all access to the backing bag is accomplished through the returned bag.

        It is imperative that the user manually synchronize on the returned bag when iterating over it: 

         SortedBag bag = BagUtils.synchronizedSortedBag(new TreeBag());
 ...
 synchronized(bag) {
     Iterator i = bag.iterator(); // Must be in synchronized block
     while (i.hasNext())
         foo(i.next());
     }
 }
        Failure to follow this advice may result in non-deterministic behavior.
        Parameters:
        bag - the bag to synchronize, must not be null
        Returns:
        a synchronized bag backed by that bag
        Throws:
        java.lang.IllegalArgumentException - if the SortedBag is null

      • unmodifiableSortedBag

        public static SortedBag unmodifiableSortedBag​(SortedBag bag)
        Deprecated.
        Returns an unmodifiable view of the given sorted bag. Any modification attempts to the returned bag will raise an UnsupportedOperationException.
        Parameters:
        bag - the bag whose unmodifiable view is to be returned, must not be null
        Returns:
        an unmodifiable view of that bag
        Throws:
        java.lang.IllegalArgumentException - if the SortedBag is null

      • predicatedSortedBag

        public static SortedBag predicatedSortedBag​(SortedBag bag,
                                            Predicate predicate)
        Deprecated.
        Returns a predicated (validating) sorted bag backed by the given sorted bag.

        Only objects that pass the test in the given predicate can be added to the bag. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original bag after invoking this method, as it is a backdoor for adding invalid objects.

        Parameters:
        bag - the sorted bag to predicate, must not be null
        predicate - the predicate for the bag, must not be null
        Returns:
        a predicated bag backed by the given bag
        Throws:
        java.lang.IllegalArgumentException - if the SortedBag or Predicate is null

      • typedSortedBag

        public static SortedBag typedSortedBag​(SortedBag bag,
                                       java.lang.Class type)
        Deprecated.
        Returns a typed sorted bag backed by the given bag.

        Only objects of the specified type can be added to the bag.

        Parameters:
        bag - the bag to limit to a specific type, must not be null
        type - the type of objects which may be added to the bag
        Returns:
        a typed bag backed by the specified bag

      • transformedSortedBag

        public static SortedBag transformedSortedBag​(SortedBag bag,
                                             Transformer transformer)
        Deprecated.
        Returns a transformed sorted bag backed by the given bag.

        Each object is passed through the transformer as it is added to the Bag. It is important not to use the original bag after invoking this method, as it is a backdoor for adding untransformed objects.

        Parameters:
        bag - the bag to predicate, must not be null
        transformer - the transformer for the bag, must not be null
        Returns:
        a transformed bag backed by the given bag
        Throws:
        java.lang.IllegalArgumentException - if the Bag or Transformer is null