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'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* Copyright (C) 2004-2014 Volker Bergmann ([email protected]).
* All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.databene.commons.iterator;
/**
* Iterates through another BidirectionalIterator repeatedly.
* This is supported forward as well as backward.
*
* Created: 12.05.2007 23:21:48
* @author Volker Bergmann
*/
public class CyclicIterator extends BidirectionalIteratorProxy {
private boolean cyclic;
public CyclicIterator(BidirectionalIterator realIterator) {
super(realIterator);
this.cyclic = true;
}
public boolean isCyclic() {
return cyclic;
}
public void setCyclic(boolean cyclic) {
this.cyclic = cyclic;
}
@Override
public boolean hasPrevious() {
return (cyclic || super.hasPrevious());
}
@Override
public boolean hasNext() {
return (cyclic || super.hasNext());
}
@Override
public E previous() {
if (super.hasPrevious())
return super.previous();
else if (cyclic)
return super.last();
else
throw new IllegalStateException("No element available for previous()");
}
@Override
public E next() {
if (super.hasNext())
return super.next();
else if (cyclic)
return super.first();
else
throw new IllegalStateException("No element available for next()");
}
}