/*
* Copyright (c) 2002-2004 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The end-user documentation included with the redistribution, if any, must
* include the following acknowledgment: "This product includes software
* developed by Sun Microsystems, Inc. for JXTA(TM) technology."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
* not be used to endorse or promote products derived from this software
* without prior written permission. For written permission, please contact
* Project JXTA at http://www.jxta.org.
*
* 5. Products derived from this software may not be called "JXTA", nor may
* "JXTA" appear in their name, without prior written permission of Sun.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SUN
* MICROSYSTEMS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of Project JXTA. For more information on Project JXTA, please see
* http://www.jxta.org.
*
* This license is based on the BSD license adopted by the Apache Foundation.
*/
package net.jxta.impl.rendezvous.rpv;
import java.util.Iterator;
import java.util.SortedSet;
/**
* Sequential
*/
class PeerViewSequentialStrategy implements PeerViewStrategy {
private final SortedSet<PeerViewDestination> set;
private PeerViewElement current;
PeerViewSequentialStrategy(SortedSet<PeerViewDestination> aset) {
set = aset;
reset();
}
/**
* {@inheritDoc}
*/
public void reset() {
current = null;
}
/**
* {@inheritDoc}
*/
public PeerViewElement next() {
synchronized (set) {
do {
if (null == current) {
if (!set.isEmpty()) {
// no current, take the first
current = (PeerViewElement) set.first();
break;
} else {
// no first, return null
break;
}
} else {
SortedSet<PeerViewDestination> tail = set.tailSet(current);
Iterator<PeerViewDestination> fromTail = tail.iterator();
if (fromTail.hasNext()) {
PeerViewDestination tailFirst = fromTail.next();
if (0 == current.compareTo(tailFirst)) {
if (fromTail.hasNext()) {
// first in tail is current so the new current
// is second in tail.
current = (PeerViewElement) fromTail.next();
break;
} else {
// none left in tail after current, start over.
current = null;
}
} else {
// current is not in the tail set, so first in tail
// is new current
current = (PeerViewElement) tailFirst;
break;
}
} else {
// none in tail, start over.
current = null;
}
}
//FIXME by hamada this does not loop, current is always null, is the intended behavior?
} while (null == current);
}
return current;
}
}