org.apache.flink.runtime.state.gemini.engine.GInternalKList 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
* 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,
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*/
package org.apache.flink.runtime.state.gemini.engine;
import org.apache.flink.runtime.state.gemini.engine.memstore.GSValue;
/**
* GInternalKList.
* K is type of key.
* V is type of List.
*/
public interface GInternalKList extends GCommonKList {
/**
* Retrieves and removes the head of the list under the given key,
* or returns {@code null} if the list is empty.
*
* @param key The key under which the elements are to be retrieved.
* @return The head of the list under the given key.
*/
GSValue poll(K key);
/**
* Retrieves, but does not remove, the head of the list under the given key,
* or returns {@code null} if the list is empty.
*
* @param key The key under which the elements are to be retrieved.
* @return The head of the list under the given key.
*/
GSValue peek(K key);
}