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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.hadoop.hbase.regionserver;

import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.KeepDeletedCells;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.yetus.audience.InterfaceStability;

/**
 * This class gives you the ability to change the max versions and TTL options before opening a
 * scanner for a Store. And also gives you some information for the scan.
 * 

* Changing max versions, min versins, KeepDeletedCells, and TTL are usually safe even for * flush/compaction, so here we provide a way to do it for you. If you want to do other complicated * operations such as filtering, please wrap the {@link InternalScanner} in the {@code preCompact} * and {@code preFlush} methods in {@link org.apache.hadoop.hbase.coprocessor.RegionObserver}. *

* For user scans, we also provide this class as a parameter in the {@code preStoreScannerOpen} * method in {@link org.apache.hadoop.hbase.coprocessor.RegionObserver}. You can use it to change * the inherent properties for a Store. For example, even if you use {@code Scan.readAllVersions}, * you still can not read two versions if the max versions property of the Store is one. You need to * set the max versions to a value greater than two in {@code preStoreScannerOpen}. * @see org.apache.hadoop.hbase.coprocessor.RegionObserver#preFlushScannerOpen(org.apache.hadoop.hbase.coprocessor.ObserverContext, * Store, ScanOptions, FlushLifeCycleTracker) * @see org.apache.hadoop.hbase.coprocessor.RegionObserver#preCompactScannerOpen(org.apache.hadoop.hbase.coprocessor.ObserverContext, * Store, ScanType, ScanOptions, * org.apache.hadoop.hbase.regionserver.compactions.CompactionLifeCycleTracker, * org.apache.hadoop.hbase.regionserver.compactions.CompactionRequest) * @see org.apache.hadoop.hbase.coprocessor.RegionObserver#preStoreScannerOpen(org.apache.hadoop.hbase.coprocessor.ObserverContext, * Store, ScanOptions) */ @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC) @InterfaceStability.Evolving public interface ScanOptions { int getMaxVersions(); void setMaxVersions(int maxVersions); default void readAllVersions() { setMaxVersions(Integer.MAX_VALUE); } long getTTL(); void setTTL(long ttl); void setKeepDeletedCells(KeepDeletedCells keepDeletedCells); KeepDeletedCells getKeepDeletedCells(); int getMinVersions(); void setMinVersions(int minVersions); long getTimeToPurgeDeletes(); void setTimeToPurgeDeletes(long ttl); /** * Returns a copy of the Scan object. Modifying it will have no effect. */ Scan getScan(); }





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