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.regionserver;
019
020import java.io.IOException;
021import java.util.function.IntConsumer;
022import org.apache.commons.lang3.NotImplementedException;
023import org.apache.hadoop.fs.Path;
024import org.apache.hadoop.hbase.Cell;
025import org.apache.hadoop.hbase.client.Scan;
026import org.apache.yetus.audience.InterfaceAudience;
027
028/**
029 * A "non-lazy" scanner which always does a real seek operation. Most scanners are inherited from
030 * this class.
031 */
032@InterfaceAudience.Private
033public abstract class NonLazyKeyValueScanner implements KeyValueScanner {
034
035  @Override
036  public boolean requestSeek(Cell kv, boolean forward, boolean useBloom) throws IOException {
037    return doRealSeek(this, kv, forward);
038  }
039
040  @Override
041  public boolean realSeekDone() {
042    return true;
043  }
044
045  @Override
046  public void enforceSeek() throws IOException {
047    throw new NotImplementedException("enforceSeek must not be called on a " + "non-lazy scanner");
048  }
049
050  public static boolean doRealSeek(KeyValueScanner scanner, Cell kv, boolean forward)
051    throws IOException {
052    return forward ? scanner.reseek(kv) : scanner.seek(kv);
053  }
054
055  @Override
056  public boolean shouldUseScanner(Scan scan, HStore store, long oldestUnexpiredTS) {
057    // No optimizations implemented by default.
058    return true;
059  }
060
061  @Override
062  public boolean isFileScanner() {
063    // Not a file by default.
064    return false;
065  }
066
067  @Override
068  public void recordBlockSize(IntConsumer blockSizeConsumer) {
069    // do nothing
070  }
071
072  @Override
073  public Path getFilePath() {
074    // Not a file by default.
075    return null;
076  }
077
078  @Override
079  public Cell getNextIndexedKey() {
080    return null;
081  }
082
083  @Override
084  public void shipped() throws IOException {
085    // do nothing
086  }
087}