2001-02-15 07:43:00 +01:00
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/* Iterator.java -- Interface for iterating over collections
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2001-10-16 07:47:01 +02:00
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Copyright (C) 1998, 2001 Free Software Foundation, Inc.
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2000-03-17 01:45:06 +01:00
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2001-02-15 07:43:00 +01:00
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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2000-03-17 01:45:06 +01:00
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package java.util;
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/**
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2001-10-16 07:47:01 +02:00
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* An object which iterates over a collection. An Iterator is used to return
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* the items once only, in sequence, by successive calls to the next method.
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* It is also possible to remove elements from the underlying collection by
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* using the optional remove method. Iterator is intended as a replacement
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* for the Enumeration interface of previous versions of Java, which did not
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* have the remove method and had less conveniently named methods.
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*
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* @author Original author unknown
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* @author Eric Blake <ebb9@email.byu.edu>
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* @see Collection
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* @see ListIterator
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* @see Enumeration
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* @since 1.2
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* @status updated to 1.4
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*/
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public interface Iterator
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{
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/**
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* Tests whether there are elements remaining in the collection. In other
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* words, calling <code>next()</code> will not throw an exception.
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*
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* @return true if there is at least one more element in the collection
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*/
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boolean hasNext();
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/**
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* Obtain the next element in the collection.
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*
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* @return the next element in the collection
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* @throws NoSuchElementException if there are no more elements
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*/
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Object next();
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/**
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* Remove from the underlying collection the last element returned by next
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* (optional operation). This method can be called only once after each
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* call to <code>next()</code>. It does not affect what will be returned
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* by subsequent calls to next.
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*
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* @throws IllegalStateException if next has not yet been called or remove
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* has already been called since the last call to next.
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* @throws UnsupportedOperationException if this Iterator does not support
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* the remove operation.
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*/
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void remove();
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}
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