com.Ostermiller.util.ArrayIterator Maven / Gradle / Ivy
/*
* Converts an array to an iterator.
* Copyright (C) 2004-2006 Stephen Ostermiller
* http://ostermiller.org/contact.pl?regarding=Java+Utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* See COPYING.TXT for details.
*/
package com.Ostermiller.util;
import java.util.*;
/**
* Converts an array to an iterator.
*
* More information about this class is available from ostermiller.org.
*
* @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
* @param Type of array over which to iterate
* @since ostermillerutils 1.03.00
*/
public class ArrayIterator implements Iterator {
/**
* Array being converted to iterator.
*/
private ElementType[] array;
/**
* Current index into the array.
*/
private int index = 0;
/**
* Whether the last element has been removed.
*/
private boolean lastRemoved = false;
/**
* Create an Iterator from an Array.
*
* @param array of objects on which to enumerate.
*
* @since ostermillerutils 1.03.00
*/
public ArrayIterator(ElementType[] array){
this.array = array;
}
/**
* Tests if this Iterator contains more elements.
*
* @return true if and only if this Iterator object contains at least
* one more element to provide; false otherwise.
*
* @since ostermillerutils 1.03.00
*/
public boolean hasNext(){
return (index < array.length);
}
/**
* Returns the next element of this Iterator if this Iterator
* object has at least one more element to provide.
*
* @return the next element of this Iterator.
* @throws NoSuchElementException if no more elements exist.
*
* @since ostermillerutils 1.03.00
*/
public ElementType next() throws NoSuchElementException {
if (index >= array.length) throw new NoSuchElementException("Array index: " + index);
ElementType object = array[index];
index++;
lastRemoved = false;
return object;
}
/**
* Removes the last object from the array by setting the slot in
* the array to null.
* This method can be called only once per call to next.
*
* @throws 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.
*
* @since ostermillerutils 1.03.00
*/
public void remove(){
if (index == 0) throw new IllegalStateException();
if (lastRemoved) throw new IllegalStateException();
array[index-1] = null;
lastRemoved = true;
}
}