sdks/java/io/jms/src/main/java/org/apache/beam/sdk/io/jms/AutoScaler.java

/*
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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
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package org.apache.beam.sdk.io.jms;

import java.io.Serializable;
import org.apache.beam.sdk.io.UnboundedSource;

/**
 * Enables users to specify their own `JMS` backlog reporters enabling {@link JmsIO} to report
 * {@link UnboundedSource.UnboundedReader#getTotalBacklogBytes()}.
 */
public interface AutoScaler extends Serializable {

  /** The {@link AutoScaler} is started when the {@link JmsIO.UnboundedJmsReader} is started. */
  void start();

  /**
   * Returns the size of the backlog of unread data in the underlying data source represented by all
   * splits of this source.
   */
  long getTotalBacklogBytes();

  /** The {@link AutoScaler} is stopped when the {@link JmsIO.UnboundedJmsReader} is closed. */
  void stop();
}