Package java.util
Interface Iterator<E>
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- Type Parameters:
E- the type of elements returned by this iterator
- All Known Subinterfaces:
ListIterator<E>
public interface Iterator<E>An iterator over a collection.Iteratortakes the place ofEnumerationin 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
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description booleanhasNext()Returnstrueif the iteration has more elements.Enext()Returns the next element in the iteration.voidremove()Removes from the underlying collection the last element returned by this iterator (optional operation).
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Method Detail
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hasNext
boolean hasNext()
Returnstrueif the iteration has more elements. (In other words, returnstrueifnext()would return an element rather than throwing an exception.)- Returns:
trueif the iteration has more elements
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next
E next()
Returns the next element in the iteration.- Returns:
- the next element in the iteration
- Throws:
NoSuchElementException- if the iteration has no more elements
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remove
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 tonext(). 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.- Throws:
UnsupportedOperationException- if theremoveoperation is not supported by this iteratorIllegalStateException- if thenextmethod has not yet been called, or theremovemethod has already been called after the last call to thenextmethod
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