/* Copyright (C) 2002 Univ. of Massachusetts Amherst, Computer Science Dept.
This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
http://www.cs.umass.edu/~mccallum/mallet
This software is provided under the terms of the Common Public License,
version 1.0, as published by http://www.opensource.org. For further
information, see the file `LICENSE' included with this distribution. */
/**
@author Andrew McCallum <a href="mailto:mccallum@cs.umass.edu">mccallum@cs.umass.edu</a>
*/
package cc.mallet.pipe.iterator;
import java.util.Iterator;
import cc.mallet.pipe.*;
import cc.mallet.types.Instance;
public class ConcatenatedInstanceIterator implements Iterator<Instance>
{
Iterator<Instance>[] iterators;
Instance next;
int iteratorIndex;
public ConcatenatedInstanceIterator (Iterator<Instance>[] iterators)
{
this.iterators = iterators;
this.iteratorIndex = 0;
setNext();
}
private void setNext () {
next = null;
for (; iteratorIndex < iterators.length &&
!iterators[iteratorIndex].hasNext(); iteratorIndex++);
if (iteratorIndex < iterators.length)
next = (Instance)iterators[iteratorIndex].next();
}
public boolean hasNext ()
{
return next != null;
}
public Instance next ()
{
Instance ret = (Instance)next;
setNext();
return ret;
}
public void remove () { throw new IllegalStateException ("This Iterator<Instance> does not support remove()."); }
}