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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to you under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    * http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.hadoop.hbase.quotas;
18  
19  import java.util.Objects;
20  
21  import org.apache.hadoop.conf.Configuration;
22  import org.apache.hadoop.hbase.classification.InterfaceAudience;
23  
24  /**
25   * Factory for creating {@link SpaceQuotaSnapshotNotifier} implementations. Implementations
26   * must have a no-args constructor.
27   */
28  @InterfaceAudience.Private
29  public class SpaceQuotaSnapshotNotifierFactory {
30    private static final SpaceQuotaSnapshotNotifierFactory INSTANCE =
31        new SpaceQuotaSnapshotNotifierFactory();
32  
33    public static final String SNAPSHOT_NOTIFIER_KEY = "hbase.master.quota.snapshot.notifier.impl";
34    public static final Class<? extends SpaceQuotaSnapshotNotifier> SNAPSHOT_NOTIFIER_DEFAULT =
35        TableSpaceQuotaSnapshotNotifier.class;
36  
37    // Private
38    private SpaceQuotaSnapshotNotifierFactory() {}
39  
40    public static SpaceQuotaSnapshotNotifierFactory getInstance() {
41      return INSTANCE;
42    }
43  
44    /**
45     * Instantiates the {@link SpaceQuotaSnapshotNotifier} implementation as defined in the
46     * configuration provided.
47     *
48     * @param conf Configuration object
49     * @return The SpaceQuotaViolationNotifier implementation
50     * @throws IllegalArgumentException if the class could not be instantiated
51     */
52    public SpaceQuotaSnapshotNotifier create(Configuration conf) {
53      Class<? extends SpaceQuotaSnapshotNotifier> clz = Objects.requireNonNull(conf)
54          .getClass(SNAPSHOT_NOTIFIER_KEY, SNAPSHOT_NOTIFIER_DEFAULT,
55              SpaceQuotaSnapshotNotifier.class);
56      try {
57        return clz.newInstance();
58      } catch (InstantiationException | IllegalAccessException e) {
59        throw new IllegalArgumentException("Failed to instantiate the implementation", e);
60      }
61    }
62  }