/*
 * 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.operator;

import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.cep.EventComparator;
import org.apache.flink.cep.PatternFlatSelectFunction;
import org.apache.flink.cep.nfa.AfterMatchSkipStrategy;
import org.apache.flink.cep.nfa.compiler.NFACompiler;
import org.apache.flink.streaming.api.operators.TimestampedCollector;
import org.apache.flink.util.OutputTag;

import java.util.List;
import java.util.Map;

/**
 * Version of {@link AbstractKeyedCEPPatternOperator} that applies given {@link PatternFlatSelectFunction} to fully matched event patterns.
 *
 * @param <IN> Type of the input elements
 * @param <KEY> Type of the key on which the input stream is keyed
 * @param <OUT> Type of the output elements
 */
public class FlatSelectCepOperator<IN, KEY, OUT>
	extends AbstractKeyedCEPPatternOperator<IN, KEY, OUT, PatternFlatSelectFunction<IN, OUT>> {
	private static final long serialVersionUID = 5845993459551561518L;

	public FlatSelectCepOperator(
		TypeSerializer<IN> inputSerializer,
		boolean isProcessingTime,
		NFACompiler.NFAFactory<IN> nfaFactory,
		EventComparator<IN> comparator,
		AfterMatchSkipStrategy skipStrategy,
		PatternFlatSelectFunction<IN, OUT> function,
		OutputTag<IN> lateDataOutputTag) {
		super(inputSerializer, isProcessingTime, nfaFactory, comparator, skipStrategy, function, lateDataOutputTag);
	}

	private transient TimestampedCollector<OUT> collector;

	@Override
	public void open() throws Exception {
		super.open();
		collector = new TimestampedCollector<>(output);
	}

	@Override
	protected void processMatchedSequences(Iterable<Map<String, List<IN>>> matchingSequences, long timestamp) throws Exception {
		for (Map<String, List<IN>> match : matchingSequences) {
			collector.setAbsoluteTimestamp(timestamp);
			getUserFunction().flatSelect(match, collector);
		}
	}

	@Override
	public void endInput() throws Exception {

	}
}