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;
021
022import org.apache.hadoop.hbase.Cell;
023import org.apache.hadoop.hbase.CellComparator;
024import org.apache.yetus.audience.InterfaceAudience;
025import org.apache.hadoop.hbase.io.hfile.HFile;
026
027/**
028 * The bloom context that is used by the StorefileWriter to add the bloom details
029 * per cell
030 */
031@InterfaceAudience.Private
032public abstract class BloomContext {
033
034  protected BloomFilterWriter bloomFilterWriter;
035  protected CellComparator comparator;
036
037  public BloomContext(BloomFilterWriter bloomFilterWriter, CellComparator comparator) {
038    this.bloomFilterWriter = bloomFilterWriter;
039    this.comparator = comparator;
040  }
041
042  public Cell getLastCell() {
043    return this.bloomFilterWriter.getPrevCell();
044  }
045
046  /**
047   * Bloom information from the cell is retrieved
048   * @param cell
049   * @throws IOException
050   */
051  public void writeBloom(Cell cell) throws IOException {
052    // only add to the bloom filter on a new, unique key
053    if (isNewKey(cell)) {
054      sanityCheck(cell);
055      bloomFilterWriter.append(cell);
056    }
057  }
058
059  private void sanityCheck(Cell cell) throws IOException {
060    if (this.getLastCell() != null) {
061      if (comparator.compare(cell, this.getLastCell()) <= 0) {
062        throw new IOException("Added a key not lexically larger than" + " previous. Current cell = "
063            + cell + ", prevCell = " + this.getLastCell());
064      }
065    }
066  }
067
068  /**
069   * Adds the last bloom key to the HFile Writer as part of StorefileWriter close.
070   * @param writer
071   * @throws IOException
072   */
073  public abstract void addLastBloomKey(HFile.Writer writer) throws IOException;
074
075  /**
076   * Returns true if the cell is a new key as per the bloom type
077   * @param cell the cell to be verified
078   * @return true if a new key else false
079   */
080  protected abstract boolean isNewKey(Cell cell);
081}