Interface: java.util.Iterator<E>

  • public interface Iterator<E>
An iterator over a collection. Iterator takes the place of Enumeration 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.

Authors:
@author Josh Bloch
See:
@see java.util.Collection
@see java.util.ListIterator
@see java.util.Enumeration
Version:
@version 1.24, 01/17/04
Since:
@since 1.2

Methods

  • hasNexttop

    public boolean hasNext()
    Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)
    Return:
    @return true if the iterator has more elements.
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  • nexttop

    public E next()
    Returns the next element in the iteration. Calling this method repeatedly until the java.util.Iterator.hasNext() method returns false will return each element in the underlying collection exactly once.
    Return:
    @return the next element in the iteration.
    Exceptions:
    @exception NoSuchElementException iteration has no more elements.
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  • removetop

    public void remove()
    Removes from the underlying collection the last element returned by the iterator (optional operation). This method can be called only once per call to 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.
    Exceptions:
    @exception UnsupportedOperationException if the remove operation is not supported by this Iterator.
    @exception IllegalStateException 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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