/*
 * 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.streaming.api.operators.collect;

import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.runtime.operators.coordination.OperatorEvent;
import org.apache.flink.runtime.operators.coordination.OperatorEventGateway;
import org.apache.flink.runtime.operators.coordination.OperatorEventHandler;
import org.apache.flink.streaming.api.operators.StreamSink;

import java.util.concurrent.CompletableFuture;

/**
 * A {@link StreamSink} that collects query results and sends them back to the client.
 *
 * @param <IN> type of results to be written into the sink.
 */
public class CollectSinkOperator<IN> extends StreamSink<IN> implements OperatorEventHandler {

    private final CollectSinkFunction<IN> sinkFunction;
    // we need operator id to identify the coordinator of this operator,
    // this is only used for in clients so no need to serialize
    private final transient CompletableFuture<OperatorID> operatorIdFuture;

    public CollectSinkOperator(
            TypeSerializer<IN> serializer, long maxBytesPerBatch, String accumulatorName) {
        super(new CollectSinkFunction<>(serializer, maxBytesPerBatch, accumulatorName));
        this.sinkFunction = (CollectSinkFunction<IN>) getUserFunction();
        this.operatorIdFuture = new CompletableFuture<>();
    }

    @Override
    public void handleOperatorEvent(OperatorEvent evt) {
        // nothing to handle
    }

    @Override
    public void close() throws Exception {
        sinkFunction.accumulateFinalResults();
        super.close();
    }

    public CompletableFuture<OperatorID> getOperatorIdFuture() {
        return operatorIdFuture;
    }

    void setOperatorEventGateway(OperatorEventGateway operatorEventGateway) {
        sinkFunction.setOperatorEventGateway(operatorEventGateway);
    }
}
