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A module that is everything required to understands Druid Segments
/*
* 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.druid.segment.loading;
import org.apache.druid.guice.annotations.ExtensionPoint;
import org.apache.druid.timeline.DataSegment;
import javax.annotation.Nullable;
/**
* DataSegmentArchiver knows how to archive segments.
* Since any implementation of DataSegmentArchiver is initialized when an ingestion job starts
* if a deep storage extension is loaded even when that deep storage is actually not used,
* implementations should avoid initializing the deep storage client immediately
* but defer it until the deep storage client is actually used.
*/
@ExtensionPoint
public interface DataSegmentArchiver
{
/**
* Perform an archive task on the segment and return the resulting segment or null if there was no action needed.
*
* @param segment The source segment
*
* @return The segment after archiving or `null` if there was no archiving performed.
*
* @throws SegmentLoadingException on error
*/
@Nullable
DataSegment archive(DataSegment segment) throws SegmentLoadingException;
/**
* Perform the restore from an archived segment and return the resulting segment or null if there was no action
*
* @param segment The source (archived) segment
*
* @return The segment after it has been unarchived
*
* @throws SegmentLoadingException on error
*/
@Nullable
DataSegment restore(DataSegment segment) throws SegmentLoadingException;
}