001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.util;
019
020import java.io.IOException;
021import org.apache.hadoop.hbase.Cell;
022import org.apache.hadoop.hbase.CellComparator;
023import org.apache.hadoop.hbase.io.hfile.HFile;
024import org.apache.yetus.audience.InterfaceAudience;
025
026/**
027 * The bloom context that is used by the StorefileWriter to add the bloom details per cell
028 */
029@InterfaceAudience.Private
030public abstract class BloomContext {
031
032  protected BloomFilterWriter bloomFilterWriter;
033  protected CellComparator comparator;
034
035  public BloomContext(BloomFilterWriter bloomFilterWriter, CellComparator comparator) {
036    this.bloomFilterWriter = bloomFilterWriter;
037    this.comparator = comparator;
038  }
039
040  public Cell getLastCell() {
041    return this.bloomFilterWriter.getPrevCell();
042  }
043
044  /**
045   * Bloom information from the cell is retrieved nn
046   */
047  public void writeBloom(Cell cell) throws IOException {
048    // only add to the bloom filter on a new, unique key
049    if (isNewKey(cell)) {
050      sanityCheck(cell);
051      bloomFilterWriter.append(cell);
052    }
053  }
054
055  private void sanityCheck(Cell cell) throws IOException {
056    if (this.getLastCell() != null) {
057      if (comparator.compare(cell, this.getLastCell()) <= 0) {
058        throw new IOException("Added a key not lexically larger than" + " previous. Current cell = "
059          + cell + ", prevCell = " + this.getLastCell());
060      }
061    }
062  }
063
064  /**
065   * Adds the last bloom key to the HFile Writer as part of StorefileWriter close. nn
066   */
067  public abstract void addLastBloomKey(HFile.Writer writer) throws IOException;
068
069  /**
070   * Returns true if the cell is a new key as per the bloom type
071   * @param cell the cell to be verified
072   * @return true if a new key else false
073   */
074  protected abstract boolean isNewKey(Cell cell);
075}