org.apache.flink.streaming.api.operators.Output Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.flink.streaming.api.operators;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.streaming.api.watermark.Watermark;
import org.apache.flink.streaming.runtime.streamrecord.LatencyMarker;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
import org.apache.flink.streaming.runtime.watermarkstatus.WatermarkStatus;
import org.apache.flink.util.Collector;
import org.apache.flink.util.OutputTag;
/**
* A {@link org.apache.flink.streaming.api.operators.StreamOperator} is supplied with an object of
* this interface that can be used to emit elements and other messages, such as barriers and
* watermarks, from an operator.
*
* @param The type of the elements that can be emitted.
*/
@PublicEvolving
public interface Output extends Collector {
/**
* Emits a {@link Watermark} from an operator. This watermark is broadcast to all downstream
* operators.
*
* A watermark specifies that no element with a timestamp lower or equal to the watermark
* timestamp will be emitted in the future.
*/
void emitWatermark(Watermark mark);
void emitWatermarkStatus(WatermarkStatus watermarkStatus);
/**
* Emits a record to the side output identified by the given {@link OutputTag}.
*
* @param record The record to collect.
*/
void collect(OutputTag outputTag, StreamRecord record);
void emitLatencyMarker(LatencyMarker latencyMarker);
}