Package org.apache.commons.collections4.collection

Class CompositeCollection<E>

java.lang.Object
org.apache.commons.collections4.collection.CompositeCollection<E>
Type Parameters:
E - the type of the elements in the collection
All Implemented Interfaces:
Serializable, Iterable<E>, Collection<E>
public class CompositeCollection<E> extends Object implements Collection<E>, Serializable
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:
3.0
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static interface 
    CompositeCollection.CollectionMutator<E>
    Pluggable strategy to handle changes to the composite.

  • Constructor Summary

    Constructors
    Constructor
    Description
    CompositeCollection()
    Create an empty CompositeCollection.
    CompositeCollection(Collection<E> compositeCollection)
    Create a Composite Collection with one collection.
    CompositeCollection(Collection<E>... compositeCollections)
    Create a Composite Collection with an array of collections.
    CompositeCollection(Collection<E> compositeCollection1, Collection<E> compositeCollection2)
    Create a Composite Collection with two collections.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    add(E obj)
    Adds an object to the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    boolean
    addAll(Collection<? extends E> coll)
    Adds a collection of elements to this collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    void
    addComposited(Collection<E> compositeCollection)
    Add these Collections to the list of collections in this composite
    void
    addComposited(Collection<E>... compositeCollections)
    Add these Collections to the list of collections in this composite
    void
    addComposited(Collection<E> compositeCollection1, Collection<E> compositeCollection2)
    Add these Collections to the list of collections in this composite
    void
    clear()
    Removes all of the elements from this collection .
    boolean
    contains(Object obj)
    Checks whether this composite collection contains the object.
    boolean
    containsAll(Collection<?> coll)
    Checks whether this composite contains all the elements in the specified collection.
    List<Collection<E>>
    getCollections()
    Gets the collections being decorated.
    boolean
    isEmpty()
    Checks whether this composite collection is empty.
    Iterator<E>
    iterator()
    Gets an iterator over all the collections in this composite.
    boolean
    remove(Object obj)
    Removes an object from the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    boolean
    removeAll(Collection<?> coll)
    Removes the elements in the specified collection from this composite collection.
    void
    removeComposited(Collection<E> coll)
    Removes a collection from the those being decorated in this composite.
    boolean
    removeIf(Predicate<? super E> filter)
    Removes all of the elements of this collection that satisfy the given predicate from this composite collection.
    boolean
    retainAll(Collection<?> coll)
    Retains all the elements in the specified collection in this composite collection, removing all others.
    void
    setMutator(CompositeCollection.CollectionMutator<E> mutator)
    Specify a CollectionMutator strategy instance to handle changes.
    int
    size()
    Gets the size of this composite collection.
    Object[]
    toArray()
    Returns an array containing all of the elements in this composite.
    <T> T[]
    toArray(T[] array)
    Returns an object array, populating the supplied array if possible.
    Collection<E>
    toCollection()
    Returns a new collection containing all of the elements

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface java.util.Collection

    equals, hashCode, parallelStream, spliterator, stream, toArray

    Methods inherited from interface java.lang.Iterable

    forEach

  • Constructor Details

    • CompositeCollection

      public CompositeCollection()
      Create an empty CompositeCollection.

    • CompositeCollection

      public CompositeCollection(Collection<E> compositeCollection)
      Create a Composite Collection with one collection.
      Parameters:
      compositeCollection - the Collection to be appended to the composite

    • CompositeCollection

      public CompositeCollection(Collection<E> compositeCollection1, Collection<E> compositeCollection2)
      Create a Composite Collection with two collections.
      Parameters:
      compositeCollection1 - the Collection to be appended to the composite
      compositeCollection2 - the Collection to be appended to the composite

    • CompositeCollection

      public CompositeCollection(Collection<E>... compositeCollections)
      Create a Composite Collection with an array of collections.
      Parameters:
      compositeCollections - the collections to composite

  • Method Details

    • 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:

    • 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>
      Type Parameters:
      T - the type of the elements in the collection
      Parameters:
      array - the array to use, populating if possible
      Returns:
      an array of all the elements in the collection

    • add

      public boolean add(E obj)
      Adds an object to the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
      Specified by:
      add in interface Collection<E>
      Parameters:
      obj - the object to add
      Returns:
      true if the collection was modified
      Throws:
      UnsupportedOperationException - if CollectionMutator hasn't been set
      UnsupportedOperationException - if add is unsupported
      ClassCastException - if the object cannot be added due to its type
      NullPointerException - if the object cannot be added because its null
      IllegalArgumentException - if the object cannot be added

    • 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

    • addAll

      public boolean addAll(Collection<? extends E> coll)
      Adds a collection of elements to this collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
      Specified by:
      addAll in interface Collection<E>
      Parameters:
      coll - the collection to add
      Returns:
      true if the collection was modified
      Throws:
      UnsupportedOperationException - if CollectionMutator hasn't been set
      UnsupportedOperationException - if add is unsupported
      ClassCastException - if the object cannot be added due to its type
      NullPointerException - if the object cannot be added because its null
      IllegalArgumentException - if the object cannot be added

    • 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

    • removeIf

      public boolean removeIf(Predicate<? super E> filter)
      Removes all of the elements of this collection that satisfy the given predicate from this composite collection.

      This implementation calls removeIf on each collection.

      Specified by:
      removeIf in interface Collection<E>
      Parameters:
      filter - a predicate which returns true for elements to be removed
      Returns:
      true if the collection was modified
      Throws:
      UnsupportedOperationException - if removeIf is unsupported
      Since:
      4.4

    • 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

    • setMutator

      public void setMutator(CompositeCollection.CollectionMutator<E> mutator)
      Specify a CollectionMutator strategy instance to handle changes.
      Parameters:
      mutator - the mutator to use

    • addComposited

      public void addComposited(Collection<E> compositeCollection)
      Add these Collections to the list of collections in this composite
      Parameters:
      compositeCollection - the Collection to be appended to the composite

    • addComposited

      public void addComposited(Collection<E> compositeCollection1, Collection<E> compositeCollection2)
      Add these Collections to the list of collections in this composite
      Parameters:
      compositeCollection1 - the Collection to be appended to the composite
      compositeCollection2 - the Collection to be appended to the composite

    • addComposited

      public void addComposited(Collection<E>... compositeCollections)
      Add these Collections to the list of collections in this composite
      Parameters:
      compositeCollections - the Collections to be appended to the composite

    • removeComposited

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

    • toCollection

      public Collection<E> toCollection()
      Returns a new collection containing all of the elements
      Returns:
      A new ArrayList containing all of the elements in this composite. The new collection is not backed by this composite.

    • getCollections

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