davidradl commented on code in PR #27071: URL: https://github.com/apache/flink/pull/27071#discussion_r2399345114
########## flink-table/flink-table-runtime/src/main/java/org/apache/flink/table/runtime/orderedmultisetstate/OrderedMultiSetState.java: ########## @@ -0,0 +1,173 @@ +/* + * 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.table.runtime.orderedmultisetstate; + +import org.apache.flink.annotation.Experimental; +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.functions.RuntimeContext; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.api.java.tuple.Tuple3; +import org.apache.flink.table.data.RowData; +import org.apache.flink.table.runtime.orderedmultisetstate.linked.LinkedMultiSetState; + +import java.io.IOException; +import java.util.Iterator; +import java.util.Optional; + +/** + * This class represents an interface for managing an ordered multi-set state in Apache Flink. It + * provides methods to add, append, and remove elements while maintaining insertion order. + * + * <p>The state supports two types of semantics for adding elements: + * + * <ul> + * <li><b>Normal Set Semantics:</b> Replaces an existing matching element with the new one. + * <li><b>Multi-Set Semantics:</b> Appends the new element, allowing duplicates. + * </ul> + * + * <p>Removal operations are supported with different result types, indicating the outcome of the + * removal process, such as whether all elements were removed, the last added element was removed, + * or no elements were removed. + * + * @param <T> The type of elements stored in the state. + */ +@Internal +@Experimental +public interface OrderedMultiSetState<T> { + + /** + * Add the given element using a normal (non-multi) set semantics: if a matching element exists + * already, replace it (the timestamp is updated). + */ + SizeChangeInfo add(T element, long timestamp) throws Exception; + + /** Add the given element using a multi-set semantics, i.e. append. */ + SizeChangeInfo append(T element, long timestamp) throws Exception; + + /** Get iterator over all remaining elements and their timestamps, in order of insertion. */ + Iterator<Tuple2<T, Long>> iterator() throws Exception; + + /** Tells whether any state exists (in the given key context). */ + boolean isEmpty() throws IOException; + + /** + * Remove the given element. If there are multiple instances of the same element, remove the + * first one in insertion order. + */ + Tuple3<RemovalResultType, Optional<T>, SizeChangeInfo> remove(T element) throws Exception; + + /** Clear the state (in the current key context). */ + void clear(); + + /** Load cache. */ + void loadCache() throws IOException; + + /** Clear caches. */ + void clearCache(); + + /** Removal Result Type. */ + enum RemovalResultType { + /** + * Nothing was removed (e.g. as a result of TTL or not matching key), the result will not + * contain any elements. + */ + NOTHING_REMOVED, + /** All elements were removed. The result will contain the last removed element. */ + ALL_REMOVED, + /** + * The most recently added element was removed. The result will contain the element added + * before it. + */ + REMOVED_LAST_ADDED, + /** + * An element was removed, it was not the most recently added, there are more elements. The + * result will not contain any elements + */ + REMOVED_OTHER Review Comment: I am curious why nothing is returned in this case, this seems inconsistent with REMOVED_LAST_ADDED which will return the element added before it. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
