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.ExtendedCell;
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(ExtendedCell kv, boolean forward, boolean useBloom)
037    throws IOException {
038    return doRealSeek(this, kv, forward);
039  }
040
041  @Override
042  public boolean realSeekDone() {
043    return true;
044  }
045
046  @Override
047  public void enforceSeek() throws IOException {
048    throw new NotImplementedException("enforceSeek must not be called on a " + "non-lazy scanner");
049  }
050
051  public static boolean doRealSeek(KeyValueScanner scanner, ExtendedCell kv, boolean forward)
052    throws IOException {
053    return forward ? scanner.reseek(kv) : scanner.seek(kv);
054  }
055
056  @Override
057  public boolean shouldUseScanner(Scan scan, HStore store, long oldestUnexpiredTS) {
058    // No optimizations implemented by default.
059    return true;
060  }
061
062  @Override
063  public boolean isFileScanner() {
064    // Not a file by default.
065    return false;
066  }
067
068  @Override
069  public void recordBlockSize(IntConsumer blockSizeConsumer) {
070    // do nothing
071  }
072
073  @Override
074  public Path getFilePath() {
075    // Not a file by default.
076    return null;
077  }
078
079  @Override
080  public ExtendedCell getNextIndexedKey() {
081    return null;
082  }
083
084  @Override
085  public void shipped() throws IOException {
086    // do nothing
087  }
088}