/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.pact.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;
}