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/*
 * 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 com.feilong.lib.collection4.iterators;

import java.util.NoSuchElementException;

/**
 * Provides an implementation of an empty iterator.
 *
 * @since 3.1
 */
abstract class AbstractEmptyIterator {

    /**
     * Constructor.
     */
    protected AbstractEmptyIterator(){
        super();
    }

    public boolean hasNext(){
        return false;
    }

    public E next(){
        throw new NoSuchElementException("Iterator contains no elements");
    }

    public boolean hasPrevious(){
        return false;
    }

    public E previous(){
        throw new NoSuchElementException("Iterator contains no elements");
    }

    public int nextIndex(){
        return 0;
    }

    public int previousIndex(){
        return -1;
    }

    public void add(@SuppressWarnings("unused") final E obj){
        throw new UnsupportedOperationException("add() not supported for empty Iterator");
    }

    public void set(@SuppressWarnings("unused") final E obj){
        throw new IllegalStateException("Iterator contains no elements");
    }

    public void remove(){
        throw new IllegalStateException("Iterator contains no elements");
    }

    public void reset(){
        // do nothing
    }

}