/*
* 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.beam.sdk.util.common;
import java.util.Iterator;
/**
* An {@link Iterator} with the ability to copy its iteration state.
*
* @param <T> the type of elements returned by this iterator
*/
public interface Reiterator<T> extends Iterator<T> {
/**
* Returns a copy of the current {@link Reiterator}. The copy's iteration
* state is logically independent of the current iterator; each may be
* advanced without affecting the other.
*
* <p>The returned {@code Reiterator} is not guaranteed to return
* referentially identical iteration results as the original
* {@link Reiterator}, although {@link Object#equals} will typically return
* true for the corresponding elements of each if the original source is
* logically immutable.
*/
Reiterator<T> copy();
}