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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.quotas;
import java.util.Map.Entry;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.yetus.audience.InterfaceAudience;
/**
* An interface for concurrently storing and updating the size of a Region.
*/
@InterfaceAudience.Private
public interface RegionSizeStore extends Iterable>, HeapSize {
/**
* Returns the size for the give region if one exists. If no size exists, {@code null} is
* returned.
* @param regionInfo The region whose size is being fetched.
* @return The size in bytes of the region or null if no size is stored.
*/
RegionSize getRegionSize(RegionInfo regionInfo);
/**
* Atomically sets the given {@code size} for a region.
* @param regionInfo An identifier for a region.
* @param size The size in bytes of the region.
*/
void put(RegionInfo regionInfo, long size);
/**
* Atomically alter the size of a region.
* @param regionInfo The region to update.
* @param delta The change in size for the region, positive or negative.
*/
void incrementRegionSize(RegionInfo regionInfo, long delta);
/**
* Removes the mapping for the given key, returning the value if one exists in the store.
* @param regionInfo The key to remove from the store
* @return The value removed from the store if one exists, otherwise null.
*/
RegionSize remove(RegionInfo regionInfo);
/**
* Returns the number of entries in the store.
* @return The number of entries in the store.
*/
int size();
/**
* Returns if the store is empty.
* @return true if there are no entries in the store, otherwise false.
*/
boolean isEmpty();
/**
* Removes all entries from the store.
*/
void clear();
}