Github user kl0u commented on a diff in the pull request: https://github.com/apache/flink/pull/6171#discussion_r198473426 --- Diff: flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/aftermatch/AfterMatchSkipStrategy.java --- @@ -0,0 +1,155 @@ +/* + * 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.cep.nfa.aftermatch; + +import org.apache.flink.cep.nfa.ComputationState; +import org.apache.flink.cep.nfa.sharedbuffer.EventId; +import org.apache.flink.cep.nfa.sharedbuffer.SharedBuffer; + +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import java.util.Map; +import java.util.Optional; + + +/** + * Indicate the skip strategy after a match process. + */ +public abstract class AfterMatchSkipStrategy implements Serializable { + + private static final long serialVersionUID = -4048930333619068531L; + + /** + * Discards every partial match that contains event of the match preceding the first of *PatternName*. + * + * @param patternName the pattern name to skip to + * @return the created AfterMatchSkipStrategy + */ + public static AfterMatchSkipStrategy skipToFirst(String patternName) { + return new SkipToFirstStrategy(patternName); + } + + /** + * Discards every partial match that contains event of the match preceding the last of *PatternName*. + * + * @param patternName the pattern name to skip to + * @return the created AfterMatchSkipStrategy + */ + public static AfterMatchSkipStrategy skipToLast(String patternName) { + return new SkipToLastStrategy(patternName); + } + + /** + * Discards every partial match that contains event of the match. + * + * @return the created AfterMatchSkipStrategy + */ + public static AfterMatchSkipStrategy skipPastLastEvent() { + return SkipPastLastStrategy.INSTANCE; + } + + /** + * Every possible match will be emitted. + * + * @return the created AfterMatchSkipStrategy + */ + public static AfterMatchSkipStrategy noSkip() { + return NoSkipStrategy.INSTANCE; + } + + /** + * Tells if the strategy may skip some matches. + * + * @return false if the strategy is NO_SKIP strategy + */ + public abstract boolean isSkipStrategy(); + + /** + * Prunes matches/partial matches based on the chosen strategy. + * + * @param partialMatches current partial matches + * @param matchedResult already completed matches + * @param sharedBuffer corresponding shared buffer + * @throws Exception thrown if could not access the state + */ + public void prune( + Collection<ComputationState> partialMatches, --- End diff -- The name `partialMatches` is misleading because we use it also with the `completedMatches`.
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