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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 org.apache.flink.runtime.util;

import java.io.IOException;

/**
 * The memory block iterator is an iterator that always buffers a block of elements
 * in memory.
 */
public interface MemoryBlockIterator
{
	/**
	 * Move the iterator to the next memory block. The next memory block starts at the first element that was not
	 * in the block before. A special case is when no record was in the block before, which happens when this
	 * function is invoked two times directly in a sequence, without calling hasNext() or next in between. Then
	 * the block moves one element.
	 * 
	 * @return True if a new memory block was loaded, false if there were no further
	 *         records and hence no further memory block.
	 *         
	 * @throws IOException Thrown, when advancing to the next block failed.
	 */
	public boolean nextBlock() throws IOException;
}