nextapp.echo.webcontainer.util.MultiIterator Maven / Gradle / Ivy
/*
* This file is part of the Echo Web Application Framework (hereinafter "Echo").
* Copyright (C) 2002-2009 NextApp, Inc.
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*/
package nextapp.echo.webcontainer.util;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* An Iterator which presents the contents of many iterators
* as a single iterator.
*/
public class MultiIterator
implements Iterator {
/** The iterators to iterate. */
private Iterator[] iterators;
/** The index of the currently iterated iterator. */
private int index = 0;
/**
* Creates a new MultiIterator.
*
* @param iterators the array of iterators across which to iterate.
*/
public MultiIterator(Iterator[] iterators) {
super();
this.iterators = iterators;
}
/**
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() {
while (index < iterators.length && !iterators[index].hasNext()) {
++index;
}
return index < iterators.length;
}
/**
* @see java.util.Iterator#next()
*/
public Object next() {
while (index < iterators.length && !iterators[index].hasNext()) {
++index;
}
if (index >= iterators.length) {
throw new NoSuchElementException();
}
Object value = iterators[index].next();
return value;
}
/**
* @see java.util.Iterator#remove()
*/
public void remove() {
throw new UnsupportedOperationException();
}
}