/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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.apache.commons.collections4.iterators;

import java.util.Iterator;

import org.apache.commons.collections4.ResettableIterator;

/**

 * Provides an implementation of an empty iterator.

 * <p>

 * This class provides an implementation of an empty iterator.

 * This class provides for binary compatibility between Commons Collections

 * 2.1.1 and 3.1 due to issues with <code>IteratorUtils</code>.

 *

 * @since 2.1.1 and 3.1

 */

public class EmptyIterator<E> extends AbstractEmptyIterator<E> implements ResettableIterator<E> {

    /**

     * Singleton instance of the iterator.

     * @since 3.1

     */

    @SuppressWarnings("rawtypes")

    public static final ResettableIterator RESETTABLE_INSTANCE = new EmptyIterator<>();

    /**

     * Singleton instance of the iterator.

     * @since 2.1.1 and 3.1

     */

    @SuppressWarnings("rawtypes")

    public static final Iterator INSTANCE = RESETTABLE_INSTANCE;

    /**

     * Get a typed resettable empty iterator instance.

     * @param <E> the element type

     * @return ResettableIterator<E>

     */

    public static <E> ResettableIterator<E> resettableEmptyIterator() {

        return RESETTABLE_INSTANCE;

    }

    /**

     * Get a typed empty iterator instance.

     * @param <E> the element type

     * @return Iterator<E>

     */

    public static <E> Iterator<E> emptyIterator() {

        return INSTANCE;

    }

    /**

     * Constructor.

     */

    protected EmptyIterator() {

        super();

    }

}