/
Boundedness.java
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/
Boundedness.java
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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.api.connector.source;
import org.apache.flink.annotation.Public;
/**
* The boundedness of a stream. A stream could either be "bounded" (a stream with finite records) or
* "unbounded" (a stream with infinite records).
*/
@Public
public enum Boundedness {
/**
* A BOUNDED stream is a stream with finite records.
*
* <p>In the context of sources, a BOUNDED stream expects the source to put a boundary of the
* records it emits. Such boundaries could be number of records, number of bytes, elapsed time,
* and so on. Such indication of how to bound a stream is typically passed to the sources via
* configurations. When the sources emit a BOUNDED stream, Flink may leverage this property to
* do specific optimizations in the execution.
*
* <p>Unlike unbounded streams, the bounded streams are usually order insensitive. That means
* the source implementations may not have to keep track of the event times or watermarks.
* Instead, a higher throughput would be preferred.
*/
BOUNDED,
/**
* A CONTINUOUS_UNBOUNDED stream is a stream with infinite records.
*
* <p>In the context of sources, an infinite stream expects the source implementation to run
* without an upfront indication to Flink that they will eventually stop. The sources may
* eventually be terminated when users cancel the jobs or some source-specific condition is met.
*
* <p>A CONTINUOUS_UNBOUNDED stream may also eventually stop at some point. But before that
* happens, Flink always assumes the sources are going to run forever.
*/
CONTINUOUS_UNBOUNDED
}