001/**
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase.regionserver.compactions;
020
021import java.io.IOException;
022import java.util.List;
023
024import org.apache.hadoop.fs.Path;
025import org.apache.hadoop.hbase.regionserver.HStoreFile;
026import org.apache.hadoop.hbase.regionserver.throttle.ThroughputController;
027import org.apache.hadoop.hbase.security.User;
028import org.apache.yetus.audience.InterfaceAudience;
029
030
031/**
032 * This class holds all "physical" details necessary to run a compaction,
033 * and abstracts away the details specific to a particular compaction.
034 * It also has compaction request with all the logical details.
035 * Hence, this class is basically the compaction.
036 */
037@InterfaceAudience.Private
038public abstract class CompactionContext {
039  protected CompactionRequestImpl request = null;
040
041  /**
042   * Called before coprocessor preCompactSelection and should filter the candidates
043   * for coprocessor; i.e. exclude the files that definitely cannot be compacted at this time.
044   * @param filesCompacting files currently compacting
045   * @return the list of files that can theoretically be compacted.
046   */
047  public abstract List<HStoreFile> preSelect(List<HStoreFile> filesCompacting);
048
049  /**
050   * Called to select files for compaction. Must fill in the request field if successful.
051   * @param filesCompacting Files currently being compacted by other compactions.
052   * @param isUserCompaction Whether this is a user compaction.
053   * @param mayUseOffPeak Whether the underlying policy may assume it's off-peak hours.
054   * @param forceMajor Whether to force major compaction.
055   * @return Whether the selection succeeded. Selection may be empty and lead to no compaction.
056   */
057  public abstract boolean select(List<HStoreFile> filesCompacting, boolean isUserCompaction,
058      boolean mayUseOffPeak, boolean forceMajor) throws IOException;
059
060  /**
061   * Forces external selection to be applied for this compaction.
062   * @param request The pre-cooked request with selection and other settings.
063   */
064  public void forceSelect(CompactionRequestImpl request) {
065    this.request = request;
066  }
067
068  public abstract List<Path> compact(ThroughputController throughputController, User user)
069      throws IOException;
070
071  public CompactionRequestImpl getRequest() {
072    assert hasSelection();
073    return this.request;
074  }
075
076  public boolean hasSelection() {
077    return this.request != null;
078  }
079}