Package org.apache.cayenne.util.commons

Class CompositeCollection<E>

  • All Implemented Interfaces:
    Iterable<E>, Collection<E>
    public class CompositeCollection<E>
extends Object
implements Collection<E>
    Decorates a collection of other collections to provide a single unified view.

    Changes made to this collection will actually be made on the decorated collection. Add and remove operations require the use of a pluggable strategy. If no strategy is provided then add and remove are unsupported.

    Since:
    4.1 NOTE: this is a simplified and type-safe version of CompositeCollection found in commons-collections v3.2.1
    Author:
    Brian McCallister, Stephen Colebourne, Phil Steitz

    • Constructor Detail

      • CompositeCollection

        public CompositeCollection()
        Create an empty CompositeCollection.

    • Method Detail

      • size

        public int size()
        Gets the size of this composite collection.

        This implementation calls size() on each collection.

        Specified by:
        size in interface Collection<E>
        Returns:
        total number of elements in all contained containers

      • isEmpty

        public boolean isEmpty()
        Checks whether this composite collection is empty.

        This implementation calls isEmpty() on each collection.

        Specified by:
        isEmpty in interface Collection<E>
        Returns:
        true if all of the contained collections are empty

      • contains

        public boolean contains​(Object obj)
        Checks whether this composite collection contains the object.

        This implementation calls contains() on each collection.

        Specified by:
        contains in interface Collection<E>
        Parameters:
        obj - the object to search for
        Returns:
        true if obj is contained in any of the contained collections

      • iterator

        public Iterator<E> iterator()
        Gets an iterator over all the collections in this composite.

        This implementation uses an IteratorChain.

        Specified by:
        iterator in interface Collection<E>
        Specified by:
        iterator in interface Iterable<E>
        Returns:
        an IteratorChain instance which supports remove(). Iteration occurs over contained collections in the order they were added, but this behavior should not be relied upon.
        See Also:
        IteratorChain

      • toArray

        public Object[] toArray()
        Returns an array containing all of the elements in this composite.
        Specified by:
        toArray in interface Collection<E>
        Returns:
        an object array of all the elements in the collection

      • toArray

        public <T> T[] toArray​(T[] array)
        Returns an object array, populating the supplied array if possible. See Collection interface for full details.
        Specified by:
        toArray in interface Collection<E>
        Parameters:
        array - the array to use, populating if possible
        Returns:
        an array of all the elements in the collection

      • remove

        public boolean remove​(Object obj)
        Removes an object from the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
        Specified by:
        remove in interface Collection<E>
        Parameters:
        obj - the object being removed
        Returns:
        true if the collection is changed
        Throws:
        UnsupportedOperationException - if removed is unsupported
        ClassCastException - if the object cannot be removed due to its type
        NullPointerException - if the object cannot be removed because its null
        IllegalArgumentException - if the object cannot be removed

      • containsAll

        public boolean containsAll​(Collection<?> coll)
        Checks whether this composite contains all the elements in the specified collection.

        This implementation calls contains() for each element in the specified collection.

        Specified by:
        containsAll in interface Collection<E>
        Parameters:
        coll - the collection to check for
        Returns:
        true if all elements contained

      • removeAll

        public boolean removeAll​(Collection<?> coll)
        Removes the elements in the specified collection from this composite collection.

        This implementation calls removeAll on each collection.

        Specified by:
        removeAll in interface Collection<E>
        Parameters:
        coll - the collection to remove
        Returns:
        true if the collection was modified
        Throws:
        UnsupportedOperationException - if removeAll is unsupported

      • retainAll

        public boolean retainAll​(Collection<?> coll)
        Retains all the elements in the specified collection in this composite collection, removing all others.

        This implementation calls retainAll() on each collection.

        Specified by:
        retainAll in interface Collection<E>
        Parameters:
        coll - the collection to remove
        Returns:
        true if the collection was modified
        Throws:
        UnsupportedOperationException - if retainAll is unsupported

      • clear

        public void clear()
        Removes all of the elements from this collection .

        This implementation calls clear() on each collection.

        Specified by:
        clear in interface Collection<E>
        Throws:
        UnsupportedOperationException - if clear is unsupported

      • addComposited

        public void addComposited​(Collection<E> c)
        Add an additional collection to this composite.
        Parameters:
        c - the collection to add

      • removeComposited

        public void removeComposited​(Collection<E> coll)
        Removes a collection from the those being decorated in this composite.
        Parameters:
        coll - collection to be removed

      • getCollections

        public Collection<Collection<E>> getCollections()
        Gets the collections being decorated.
        Returns:
        Unmodifiable collection of all collections in this composite.