Iterator (Java Platform SE 7 ) (original) (raw)

• Type Parameters:
  E - the type of elements returned by this iterator
  All Known Subinterfaces:
  ListIterator, 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, Iterable

• • Method Summary

  Methods

  Modifier and Type	Method and Description
  boolean	hasNext() Returns true if the iteration has more elements.
  E	next() Returns the next element in the iteration.
  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%28%29) 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  
     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%28%29). 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](../../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

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