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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.regionserver.compactions;
20  
21  import java.io.IOException;
22  import java.util.List;
23  
24  import org.apache.hadoop.hbase.classification.InterfaceAudience;
25  import org.apache.hadoop.fs.Path;
26  import org.apache.hadoop.hbase.regionserver.StoreFile;
27  import org.apache.hadoop.hbase.regionserver.throttle.ThroughputController;
28  import org.apache.hadoop.hbase.security.User;
29  
30  
31  /**
32   * This class holds all "physical" details necessary to run a compaction,
33   * and abstracts away the details specific to a particular compaction.
34   * It also has compaction request with all the logical details.
35   * Hence, this class is basically the compaction.
36   */
37  @InterfaceAudience.Private
38  public abstract class CompactionContext {
39    protected CompactionRequest request = null;
40  
41    /**
42     * Called before coprocessor preCompactSelection and should filter the candidates
43     * for coprocessor; i.e. exclude the files that definitely cannot be compacted at this time.
44     * @param filesCompacting files currently compacting
45     * @return the list of files that can theoretically be compacted.
46     */
47    public abstract List<StoreFile> preSelect(final List<StoreFile> filesCompacting);
48  
49    /**
50     * Called to select files for compaction. Must fill in the request field if successful.
51     * @param filesCompacting Files currently being compacted by other compactions.
52     * @param isUserCompaction Whether this is a user compaction.
53     * @param mayUseOffPeak Whether the underlying policy may assume it's off-peak hours.
54     * @param forceMajor Whether to force major compaction.
55     * @return Whether the selection succeeded. Selection may be empty and lead to no compaction.
56     */
57    public abstract boolean select(
58        final List<StoreFile> filesCompacting, final boolean isUserCompaction,
59        final boolean mayUseOffPeak, final boolean forceMajor) throws IOException;
60  
61    /**
62     * Forces external selection to be applied for this compaction.
63     * @param request The pre-cooked request with selection and other settings.
64     */
65    public void forceSelect(CompactionRequest request) {
66      this.request = request;
67    }
68  
69    public abstract List<Path> compact(ThroughputController throughputController, User user)
70        throws IOException;
71  
72    public CompactionRequest getRequest() {
73      assert hasSelection();
74      return this.request;
75    }
76  
77    public boolean hasSelection() {
78      return this.request != null;
79    }
80  }