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/*
* esodata - data structures and other things, of varying utility
* Copyright 2022, Ben Culkin
*
* 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 3 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package bjc.data;
import java.util.Iterator;
/**
* An iterator that repeats elements from a provided iterable.
*
* @author EVE
*
* @param <E>
* The type of the iterable.
*/
public class CircularIterator<E> implements Iterator<E> {
/* The iterable, and our current iterator into it. */
private Iterable<E> source;
private Iterator<E> curr;
/* Our current element. */
private E curElm;
/*
* Should we actually get new iterators, or just repeat the last element?
*/
private boolean doCircle;
/**
* Create a new circular iterator.
*
* @param src
* The iterable to iterate from.
*
* @param circ
* Should we actually do circular iteration, or just repeat the
* terminal element?
*/
public CircularIterator(final Iterable<E> src, final boolean circ) {
source = src;
curr = source.iterator();
doCircle = circ;
}
/**
* Create a new circular iterator that does actual circular iteration.
*
* @param src
* The iterable to iterate from.
*/
public CircularIterator(final Iterable<E> src) {
this(src, true);
}
@Override
public boolean hasNext() {
/* We always have something. */
return true;
}
@Override
public E next() {
if (!curr.hasNext()) {
if (!doCircle) {
return curElm;
}
curr = source.iterator();
}
curElm = curr.next();
return curElm;
}
@Override
public void remove() {
curr.remove();
}
}
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