org.apache.flink.runtime.operators.util.CoGroupTaskIterator Maven / Gradle / Ivy
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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
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.operators.util;
import java.io.IOException;
import org.apache.flink.runtime.memory.MemoryAllocationException;
/**
* Interface describing the methods that have to be implemented by local strategies for the CoGroup Pact.
*
* @param The generic type of the first input's data type.
* @param The generic type of the second input's data type.
*/
public interface CoGroupTaskIterator {
/**
* General-purpose open method.
*
* @throws IOException
* @throws MemoryAllocationException
* @throws InterruptedException
*/
void open() throws IOException, MemoryAllocationException, InterruptedException;
/**
* General-purpose close method.
*/
void close();
/**
* Moves the internal pointer to the next key (if present). Returns true if the operation was
* successful or false if no more keys are present.
*
* The key is not necessarily shared by both inputs. In that case an empty iterator is
* returned by getValues1() or getValues2().
*
* @return true on success, false if no more keys are present
* @throws IOException
*/
boolean next() throws IOException;
/**
* Returns an iterable over the left input values for the current key.
*
* @return an iterable over the left input values for the current key.
*/
Iterable getValues1();
/**
* Returns an iterable over the left input values for the current key.
*
* @return an iterable over the left input values for the current key.
*/
Iterable getValues2();
}