T - the type of the collection elementspublic class ConcatCollection<T> extends AbstractCollection<T> implements Cloneable, Serializable
Collections
provide concatenation only through
Collection.addAll(collection) in
O(n) time. Also note that
Stream.concat(Stream, Stream)
discourages repeated concatenation. The Collection is useful e.g. for
accumulating partial results in the combine phase of
RecursiveTasks, when subtasks
return a collection of elements which are to be combined into one flat
collection.The characteristics of this implementation include the following:
O(1) time concatenation.null values.iterator() returns the elements
in the order they were added).Cloneable.Iterator.remove() operation in
O(1) time.Spliterator is optimized for lower temporary memory usage
compared to the default Spliterator. It is
Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED.
| Constructor and Description |
|---|
ConcatCollection()
Creates a new empty ConcatCollection instance.
|
ConcatCollection(Collection<? extends T> collection)
Creates a new ConcatCollection instance and adds all elements of the given
collection.
|
| Modifier and Type | Method and Description |
|---|---|
boolean |
add(T newElement) |
void |
clear() |
ConcatCollection<T> |
clone()
Returns a shallow copy of this collection.
|
void |
concat(ConcatCollection<T> other)
Returns the concatenation of this and the other collection.
|
boolean |
detectCycle()
Returns true, if an internal cycle is detected.
|
boolean |
equals(Object obj)
Compares this collection with the given object.
|
int |
hashCode() |
Iterator<T> |
iterator() |
int |
size() |
Spliterator<T> |
spliterator() |
addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toStringfinalize, getClass, notify, notifyAll, wait, wait, waitparallelStream, removeIf, streampublic ConcatCollection()
public ConcatCollection(Collection<? extends T> collection)
collection - if not null, all elements of the collection are added to
this ConcatCollectionpublic Iterator<T> iterator()
iterator in interface Iterable<T>iterator in interface Collection<T>iterator in class AbstractCollection<T>public Spliterator<T> spliterator()
NOTE:
While the iterator supports a save
remove operation, the Spliterator does not! This
collection must not be changed during spliteration.
Implementation note:
This Spliterator is more memory efficient than the default
Spliterators.spliterator(Collection, int)
by avoiding to copy all elements into an array and directly operating on
internal node objects.
spliterator in interface Iterable<T>spliterator in interface Collection<T>ConcurrentModificationException - if the collections change during
comparisonpublic int size()
size in interface Collection<T>size in class AbstractCollection<T>public boolean add(T newElement)
add in interface Collection<T>add in class AbstractCollection<T>public void clear()
clear in interface Collection<T>clear in class AbstractCollection<T>public void concat(ConcatCollection<T> other)
O(1) time by direct connection of
internal nodes. Note, that changes made to the other collection after the
concatenation will be reflected in the resulting collection.
NOTE: The caller is responsible for not concatenating the same ConcatCollection instance twice, otherwise [spl]iteration will result in endless loops!
other - the other collectiondetectCycle()public boolean detectCycle()
concatenated
twice. This method is primarily for testing and debugging purposes.concat(ConcatCollection)public boolean equals(Object obj)
equals in interface Collection<T>equals in class Objectobj - the other object to compareConcurrentModificationException - if the collections change during
comparisonpublic int hashCode()
hashCode in interface Collection<T>hashCode in class Objectpublic ConcatCollection<T> clone() throws CloneNotSupportedException
clone in class ObjectCloneNotSupportedException - this class will never throw a
CloneNotSupportedException, whereas a specialized class might do so