Iterator (Java Platform SE 8 ) (original) (raw)
- Type Parameters:
E
- the type of elements returned by this iterator
All Known Subinterfaces:
ListIterator, PrimitiveIterator<T,T_CONS>, PrimitiveIterator.OfDouble, PrimitiveIterator.OfInt, PrimitiveIterator.OfLong, XMLEventReader
All Known Implementing Classes:
BeanContextSupport.BCSIterator, EventReaderDelegate, Scanner
public interface Iterator
An iterator over a collection. Iterator
takes the place ofEnumeration in the Java Collections Framework. Iterators differ from enumerations in two ways:
Iterators allow the caller to remove elements from the underlying collection during the iteration with well-defined semantics.
Method names have been improved.
This interface is a member of the Java Collections Framework.
Since:
1.2
See Also:
Collection, ListIterator, IterableMethod Summary
All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type Method Description default void forEachRemaining(Consumer<? super E> action) Performs the given action for each remaining element until all elements have been processed or the action throws an exception. boolean hasNext() Returns true if the iteration has more elements. E next() Returns the next element in the iteration. default void remove() Removes from the underlying collection the last element returned by this iterator (optional operation). Method Detail
* #### hasNext boolean hasNext() Returns `true` if the iteration has more elements. (In other words, returns `true` if [next()](../../java/util/Iterator.html#next--) would return an element rather than throwing an exception.) Returns: `true` if the iteration has more elements * #### next [E](../../java/util/Iterator.html "type parameter in Iterator") next() Returns the next element in the iteration. Returns: the next element in the iteration Throws: `[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if the iteration has no more elements * #### remove default void remove() Removes from the underlying collection the last element returned by this iterator (optional operation). This method can be called only once per call to [next()](../../java/util/Iterator.html#next--). The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method. Implementation Requirements: The default implementation throws an instance of[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang") and performs no other action. Throws: `[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the `remove` operation is not supported by this iterator `[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if the `next` method has not yet been called, or the `remove` method has already been called after the last call to the `next` method * #### forEachRemaining default void forEachRemaining([Consumer](../../java/util/function/Consumer.html "interface in java.util.function")<? super [E](../../java/util/Iterator.html "type parameter in Iterator")> action) Performs the given action for each remaining element until all elements have been processed or the action throws an exception. Actions are performed in the order of iteration, if that order is specified. Exceptions thrown by the action are relayed to the caller. Implementation Requirements: The default implementation behaves as if: ``` while (hasNext()) action.accept(next()); ``` Parameters: `action` \- The action to be performed for each element Throws: `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified action is null Since: 1.8
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