Package org.apache.commons.collections4.set

Class CompositeSet<E>

java.lang.Object
org.apache.commons.collections4.set.CompositeSet<E>
Type Parameters:
E - the type of the elements in this set
All Implemented Interfaces:
Serializable, Iterable<E>, Collection<E>, Set<E>
public class CompositeSet<E> extends Object implements Set<E>, Serializable
Decorates a set of other sets to provide a single unified view.

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

From version 4.0, this class does not extend CompositeCollection anymore due to its input restrictions (only accepts Sets). See COLLECTIONS-424 for more details.

Since:
3.0
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static interface 
    CompositeSet.SetMutator<E>
    Defines callbacks for mutation operations.

  • Constructor Summary

    Constructors
    Constructor
    Description
    CompositeSet()
    Creates an empty CompositeSet.
    CompositeSet(Set<E> set)
    Creates a CompositeSet with just set composited.
    CompositeSet(Set<E>... sets)
    Creates a composite set with sets as the initial set of composited Sets.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    add(E obj)
    Adds an object to the collection, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
    boolean
    addAll(Collection<? extends E> coll)
    Adds a collection of elements to this composite, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
    void
    addComposited(Set<E> set)
    Adds a Set to this composite.
    void
    addComposited(Set<E>... sets)
    Adds these Sets to the list of sets in this composite
    void
    addComposited(Set<E> set1, Set<E> set2)
    Adds these Sets to the list of sets in this composite.
    void
    clear()
    Removes all of the elements from this composite set.
    boolean
    contains(Object obj)
    Checks whether this composite set contains the object.
    boolean
    containsAll(Collection<?> coll)
    Checks whether this composite contains all the elements in the specified collection.
    boolean
    equals(Object obj)
    protected CompositeSet.SetMutator<E>
    getMutator()
    Gets the set mutator to be used for this CompositeSet.
    List<Set<E>>
    getSets()
    Gets the sets being decorated.
    int
    hashCode()
    boolean
    isEmpty()
    Checks whether this composite set is empty.
    Iterator<E>
    iterator()
    Gets an iterator over all the sets in this composite.
    boolean
    remove(Object obj)
    If a CollectionMutator is defined for this CompositeSet then this method will be called anyway.
    boolean
    removeAll(Collection<?> coll)
    Removes the elements in the specified collection from this composite set.
    void
    removeComposited(Set<E> set)
    Removes a set from those being decorated in this composite.
    boolean
    removeIf(Predicate<? super E> filter)
     
    boolean
    retainAll(Collection<?> coll)
    Retains all the elements in the specified collection in this composite set, removing all others.
    void
    setMutator(CompositeSet.SetMutator<E> mutator)
    Specify a SetMutator strategy instance to handle changes.
    int
    size()
    Gets the size of this composite set.
    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.
    Set<E>
    toSet()
    Returns a new Set containing all of the elements.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface java.util.Collection

    parallelStream, stream

    Methods inherited from interface java.lang.Iterable

    forEach

    Methods inherited from interface java.util.Set

    spliterator

  • Constructor Details

    • CompositeSet

      public CompositeSet()
      Creates an empty CompositeSet.

    • CompositeSet

      public CompositeSet(Set<E> set)
      Creates a CompositeSet with just set composited.
      Parameters:
      set - the initial set in the composite

    • CompositeSet

      public CompositeSet(Set<E>... sets)
      Creates a composite set with sets as the initial set of composited Sets.
      Parameters:
      sets - the initial sets in the composite

  • Method Details

    • add

      public boolean add(E obj)
      Adds an object to the collection, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
      Specified by:
      add in interface Collection<E>
      Specified by:
      add in interface Set<E>
      Parameters:
      obj - the object to add
      Returns:
      true if the collection was modified
      Throws:
      UnsupportedOperationException - if SetMutator hasn't been set or 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

    • addAll

      public boolean addAll(Collection<? extends E> coll)
      Adds a collection of elements to this composite, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
      Specified by:
      addAll in interface Collection<E>
      Specified by:
      addAll in interface Set<E>
      Parameters:
      coll - the collection to add
      Returns:
      true if the composite was modified
      Throws:
      UnsupportedOperationException - if SetMutator hasn't been set or 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

    • addComposited

      public void addComposited(Set<E> set)
      Adds a Set to this composite.
      Parameters:
      set - the set to add
      Throws:
      IllegalArgumentException - if a SetMutator is set, but fails to resolve a collision
      UnsupportedOperationException - if there is no SetMutator set
      NullPointerException - if set is null
      See Also:

    • addComposited

      public void addComposited(Set<E>... sets)
      Adds these Sets to the list of sets in this composite
      Parameters:
      sets - the Sets to be appended to the composite

    • addComposited

      public void addComposited(Set<E> set1, Set<E> set2)
      Adds these Sets to the list of sets in this composite.
      Parameters:
      set1 - the first Set to be appended to the composite
      set2 - the second Set to be appended to the composite

    • clear

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

      This implementation calls clear() on each set.

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

    • contains

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

      This implementation calls contains() on each set.

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

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

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in interface Collection<E>
      Specified by:
      equals in interface Set<E>
      Overrides:
      equals in class Object
      See Also:

    • getMutator

      protected CompositeSet.SetMutator<E> getMutator()
      Gets the set mutator to be used for this CompositeSet.
      Returns:
      the set mutator

    • getSets

      public List<Set<E>> getSets()
      Gets the sets being decorated.
      Returns:
      Unmodifiable list of all sets in this composite.

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Collection<E>
      Specified by:
      hashCode in interface Set<E>
      Overrides:
      hashCode in class Object
      See Also:

    • isEmpty

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

      This implementation calls isEmpty() on each set.

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

    • iterator

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

      This implementation uses an IteratorChain.

      Specified by:
      iterator in interface Collection<E>
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface Set<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:

    • remove

      public boolean remove(Object obj)
      If a CollectionMutator is defined for this CompositeSet then this method will be called anyway.
      Specified by:
      remove in interface Collection<E>
      Specified by:
      remove in interface Set<E>
      Parameters:
      obj - object to be removed
      Returns:
      true if the object is removed, false otherwise

    • removeAll

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

      This implementation calls removeAll on each collection.

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

    • removeComposited

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

    • removeIf

      public boolean removeIf(Predicate<? super E> filter)
      Specified by:
      removeIf in interface Collection<E>
      Since:
      4.4

    • retainAll

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

      This implementation calls retainAll() on each collection.

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

    • setMutator

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

    • size

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

      This implementation calls size() on each set.

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

    • toArray

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

    • toSet

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