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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 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 com.rapiddweller.common.iterator;

/**
 * Iterates through another BidirectionalIterator repeatedly.
 * This is supported forward as well as backward.
 * Created: 12.05.2007 23:21:48
 *
 * @param  the type to iterate
 * @author Volker Bergmann
 */
public class CyclicIterator extends BidirectionalIteratorProxy {

  private boolean cyclic;

  /**
   * Instantiates a new Cyclic iterator.
   *
   * @param realIterator the real iterator
   */
  public CyclicIterator(BidirectionalIterator realIterator) {
    super(realIterator);
    this.cyclic = true;
  }

  /**
   * Is cyclic boolean.
   *
   * @return the boolean
   */
  public boolean isCyclic() {
    return cyclic;
  }

  /**
   * Sets cyclic.
   *
   * @param cyclic the 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()");
    }
  }
}