src/org/jivesoftware/smack/util/collections/AbstractEmptyIterator.java

// GenericsNote: Converted.
/*
 *  Copyright 2004 The Apache Software Foundation
 *
 *  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.jivesoftware.smack.util.collections;

import java.util.NoSuchElementException;

/**
 * Provides an implementation of an empty iterator.
 *
 * @author Matt Hall, John Watkinson, Stephen Colebourne
 * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:24 $
 * @since Commons Collections 3.1
 */
abstract class AbstractEmptyIterator <E> {

    /**
     * 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(E obj) {
        throw new UnsupportedOperationException("add() not supported for empty Iterator");
    }

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

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

    public E getKey() {
        throw new IllegalStateException("Iterator contains no elements");
    }

    public E getValue() {
        throw new IllegalStateException("Iterator contains no elements");
    }

    public E setValue(E value) {
        throw new IllegalStateException("Iterator contains no elements");
    }

    public void reset() {
        // do nothing
    }

}