Iterable

AI-generated Key Takeaways

• The Iterable interface enables objects to be used in "for-each" loops for easy element iteration.

• It provides methods like forEach, iterator, and spliterator for traversing elements.

• forEach applies a given action to each element, while iterator returns an Iterator for step-by-step traversal.

• spliterator offers a Spliterator for potentially parallel iteration.

• Numerous Java Collections Framework classes, like Collection, List, Set, and Queue, implement this interface.

public interface Iterable implements NSFastEnumeration

Known Indirect Subclasses AbstractCollection<E>, AbstractList<E>, AbstractQueue<E>, AbstractSequentialList<E>, AbstractSet<E>, ArrayBlockingQueue<E>, ArrayDeque<E>, ArrayList<E>, BatchUpdateException, BlockingDeque<E>, BlockingQueue<E>, Collection<E>, ConcurrentHashMap.KeySetView<K, V>, ConcurrentLinkedDeque<E>, ConcurrentLinkedQueue<E>, and 44 others. AbstractCollection<E> This class provides a skeletal implementation of the Collection interface, to minimize the effort required to implement this interface.  AbstractList<E> This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface backed by a "random access" data store (such as an array).  AbstractQueue<E> This class provides skeletal implementations of some Queue operations.  AbstractSequentialList<E> This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list).  AbstractSet<E> This class provides a skeletal implementation of the Set interface to minimize the effort required to implement this interface.  ArrayBlockingQueue<E> A bounded {@linkplain BlockingQueue blocking queue} backed by an array.  ArrayDeque<E> Resizable-array implementation of the Deque interface.  ArrayList<E> Resizable-array implementation of the List interface.  BatchUpdateException The subclass of SQLException thrown when an error occurs during a batch update operation.  BlockingDeque<E> A Deque that additionally supports blocking operations that wait for the deque to become non-empty when retrieving an element, and wait for space to become available in the deque when storing an element.  BlockingQueue<E> A Queue that additionally supports operations that wait for the queue to become non-empty when retrieving an element, and wait for space to become available in the queue when storing an element.  Collection<E> The root interface in the collection hierarchy.  ConcurrentHashMap.KeySetView<K, V> A view of a ConcurrentHashMap as a Set of keys, in which additions may optionally be enabled by mapping to a common value.  ConcurrentLinkedDeque<E> An unbounded concurrent {@linkplain Deque deque} based on linked nodes.  ConcurrentLinkedQueue<E> An unbounded thread-safe {@linkplain Queue queue} based on linked nodes.  ConcurrentSkipListSet<E> A scalable concurrent NavigableSet implementation based on a ConcurrentSkipListMap.  CopyOnWriteArrayList<E> A thread-safe variant of ArrayList in which all mutative operations (add, set, and so on) are implemented by making a fresh copy of the underlying array.  CopyOnWriteArraySet<E> A Set that uses an internal CopyOnWriteArrayList for all of its operations.  DataTruncation An exception thrown as a DataTruncation exception (on writes) or reported as a DataTruncation warning (on reads) when a data values is unexpectedly truncated for reasons other than its having execeeded MaxFieldSize.  DelayQueue<E extends Delayed> An unbounded {@linkplain BlockingQueue blocking queue} of Delayed elements, in which an element can only be taken when its delay has expired.  Deque<E> A linear collection that supports element insertion and removal at both ends.  DirectoryStream<T> An object to iterate over the entries in a directory.  EnumSet<E extends Enum<E>> A specialized Set implementation for use with enum types.  HashSet<E> This class implements the Set interface, backed by a hash table (actually a HashMap instance).  LinkedBlockingDeque<E> An optionally-bounded {@linkplain BlockingDeque blocking deque} based on linked nodes.  LinkedBlockingQueue<E> An optionally-bounded {@linkplain BlockingQueue blocking queue} based on linked nodes.  LinkedHashSet<E> Hash table and linked list implementation of the Set interface, with predictable iteration order.  LinkedList<E> Doubly-linked list implementation of the List and Deque interfaces.  LinkedTransferQueue<E> An unbounded TransferQueue based on linked nodes.  List<E> An ordered collection (also known as a sequence).  NavigableSet<E> A SortedSet extended with navigation methods reporting closest matches for given search targets.  Path An object that may be used to locate a file in a file system.  PriorityBlockingQueue<E> An unbounded {@linkplain BlockingQueue blocking queue} that uses the same ordering rules as class PriorityQueue and supplies blocking retrieval operations.  PriorityQueue<E> An unbounded priority {@linkplain Queue queue} based on a priority heap.  Queue<E> A collection designed for holding elements prior to processing.  SQLClientInfoException The subclass of SQLException is thrown when one or more client info properties could not be set on a Connection.  SQLDataException The subclass of SQLException thrown when the SQLState class value is '22', or under vendor-specified conditions.  SQLException An exception that provides information on a database access error or other errors.  SQLFeatureNotSupportedException The subclass of SQLException thrown when the SQLState class value is '0A' ( the value is 'zero' A).  SQLIntegrityConstraintViolationException The subclass of SQLException thrown when the SQLState class value is '23', or under vendor-specified conditions.  SQLInvalidAuthorizationSpecException The subclass of SQLException thrown when the SQLState class value is '28', or under vendor-specified conditions.  SQLNonTransientConnectionException The subclass of SQLException thrown for the SQLState class value '08', or under vendor-specified conditions.  SQLNonTransientException The subclass of SQLException thrown when an instance where a retry of the same operation would fail unless the cause of the SQLException is corrected.  SQLRecoverableException The subclass of SQLException thrown in situations where a previously failed operation might be able to succeed if the application performs some recovery steps and retries the entire transaction or in the case of a distributed transaction, the transaction branch.  SQLSyntaxErrorException The subclass of SQLException thrown when the SQLState class value is '42', or under vendor-specified conditions.  SQLTimeoutException The subclass of SQLException thrown when the timeout specified by Statement has expired.  SQLTransactionRollbackException The subclass of SQLException thrown when the SQLState class value is '40', or under vendor-specified conditions.  SQLTransientConnectionException The subclass of SQLException for the SQLState class value '08', or under vendor-specified conditions.  SQLTransientException The subclass of SQLException is thrown in situations where a previoulsy failed operation might be able to succeed when the operation is retried without any intervention by application-level functionality.  SQLWarning An exception that provides information on database access warnings.  SecureDirectoryStream<T> A DirectoryStream that defines operations on files that are located relative to an open directory.  ServiceLoader<S> A simple service-provider loading facility.  Set<E> A collection that contains no duplicate elements.  SortedSet<E> A Set that further provides a total ordering on its elements.  Stack<E> The Stack class represents a last-in-first-out (LIFO) stack of objects.  SynchronousQueue<E> A {@linkplain BlockingQueue blocking queue} in which each insert operation must wait for a corresponding remove operation by another thread, and vice versa.  TransferQueue<E> A BlockingQueue in which producers may wait for consumers to receive elements.  TreeSet<E> A NavigableSet implementation based on a TreeMap.  Vector<E> The Vector class implements a growable array of objects.

Implementing this interface allows an object to be the target of the "for-each loop" statement. See For-each Loop

Public Method Summary

void	forEach(Consumer<? super T> action) Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception.
abstract Iterator<T>	iterator() Returns an iterator over elements of type T.
Spliterator<T>	spliterator() Creates a Spliterator over the elements described by this Iterable.

Public Methods

public void forEach (Consumer<? super T> action)

Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception. Unless otherwise specified by the implementing class, actions are performed in the order of iteration (if an iteration order is specified). Exceptions thrown by the action are relayed to the caller.

Parameters

action	The action to be performed for each element

Throws

NullPointerException	if the specified action is null

public abstract Iterator<T> iterator ()

Returns an iterator over elements of type T.

Returns

• an Iterator.

public Spliterator<T> spliterator ()

Creates a Spliterator over the elements described by this Iterable.

Returns

• a Spliterator over the elements described by this Iterable.