/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
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; version 2 of the License.
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Oct 28, 2008
*/
package com.bigdata.relation.accesspath;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.NoSuchElementException;
import java.util.concurrent.TimeUnit;
/**
* An {@link IAsynchronousIterator} that may be serialized and sent to a remote
* JVM for consumption. Since all data to be visited is supplied to the ctor,
* the client will be able consume the data without waiting.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class ThickAsynchronousIterator<E> implements IAsynchronousIterator<E>,
Serializable {
/**
*
*/
private static final long serialVersionUID = -5166933016517242441L;
private transient boolean open = true;
/**
* Index of the last element visited by {@link #next()} and <code>-1</code>
* if NO elements have been visited.
*/
private int lastIndex;
/**
* The array of elements to be visited by the iterator.
*/
private final E[] a;
/**
* Create a thick iterator.
*
* @param a
* The array of elements to be visited by the iterator (may be
* empty, but may not be <code>null</code>).
*
* @throws IllegalArgumentException
* if <i>a</i> is <code>null</code>.
*/
public ThickAsynchronousIterator(final E[] a) {
if (a == null)
throw new IllegalArgumentException();
this.a = a;
lastIndex = -1;
}
// private final void assertOpen() {
//
// if (!open)
// throw new IllegalStateException();
//
// }
public boolean hasNext() {
if(open && lastIndex + 1 < a.length)
return true;
close();
return false;
}
public E next() {
if (!hasNext())
throw new NoSuchElementException();
return a[++lastIndex];
}
public void remove() {
throw new UnsupportedOperationException();
}
/*
* ICloseableIterator.
*/
public void close() {
open = false;
}
/*
* IAsynchronousIterator.
*/
public boolean isExhausted() {
return !hasNext();
}
/**
* Delegates to {@link #hasNext()} since all data are local and timeouts can
* not occur.
*/
public boolean hasNext(long timeout, TimeUnit unit) {
return hasNext();
}
/**
* Delegates to {@link #next()} since all data are local and timeouts can
* not occur.
*/
public E next(long timeout, TimeUnit unit) {
return next();
}
private void readObject(ObjectInputStream in) throws IOException,
ClassNotFoundException {
in.defaultReadObject();
open = true;
}
}