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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,
 * 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;

import org.apache.flink.api.common.functions.Function;
import org.apache.flink.util.Collector;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

/**
 * Base interface for a pattern timeout function which can produce multiple resulting elements. A
 * pattern flat timeout function is called with a map of partial events which are identified by
 * their names and the timestamp when the timeout occurred. The names are defined by the {@link
 * org.apache.flink.cep.pattern.Pattern} specifying the sought-after pattern. Additionally, a
 * collector is provided as a parameter. The collector is used to emit an arbitrary number of
 * resulting elements.
 *
 * {@code
 * PatternStream pattern = ...
 *
 * DataStream result = pattern.flatSelect(..., new MyPatternFlatTimeoutFunction());
 * }
 *
 * @param 
 * @param 
 */
public interface PatternFlatTimeoutFunction extends Function, Serializable {

    /**
     * Generates zero or more resulting timeout elements given a map of partial pattern events and
     * the timestamp of the timeout. The events are identified by their specified names.
     *
     * @param pattern Map containing the partial pattern. Events are identified by their names.
     * @param timeoutTimestamp Timestamp when the timeout occurred
     * @param out Collector used to output the generated elements
     * @throws Exception This method may throw exceptions. Throwing an exception will cause the
     *     operation to fail and may trigger recovery.
     */
    void timeout(Map> pattern, long timeoutTimestamp, Collector out)
            throws Exception;
}