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.Collections;
022import java.util.Set;
023import java.util.function.IntConsumer;
024import org.apache.commons.lang3.NotImplementedException;
025import org.apache.hadoop.fs.Path;
026import org.apache.hadoop.hbase.ExtendedCell;
027import org.apache.hadoop.hbase.client.Scan;
028import org.apache.yetus.audience.InterfaceAudience;
029
030/**
031 * A "non-lazy" scanner which always does a real seek operation. Most scanners are inherited from
032 * this class.
033 */
034@InterfaceAudience.Private
035public abstract class NonLazyKeyValueScanner implements KeyValueScanner {
036
037  @Override
038  public boolean requestSeek(ExtendedCell kv, boolean forward, boolean useBloom)
039    throws IOException {
040    return doRealSeek(this, kv, forward);
041  }
042
043  @Override
044  public boolean realSeekDone() {
045    return true;
046  }
047
048  @Override
049  public void enforceSeek() throws IOException {
050    throw new NotImplementedException("enforceSeek must not be called on a " + "non-lazy scanner");
051  }
052
053  public static boolean doRealSeek(KeyValueScanner scanner, ExtendedCell kv, boolean forward)
054    throws IOException {
055    return forward ? scanner.reseek(kv) : scanner.seek(kv);
056  }
057
058  @Override
059  public boolean shouldUseScanner(Scan scan, HStore store, long oldestUnexpiredTS) {
060    // No optimizations implemented by default.
061    return true;
062  }
063
064  @Override
065  public boolean isFileScanner() {
066    // Not a file by default.
067    return false;
068  }
069
070  @Override
071  public void recordBlockSize(IntConsumer blockSizeConsumer) {
072    // do nothing
073  }
074
075  @Override
076  public Path getFilePath() {
077    // Not a file by default.
078    return null;
079  }
080
081  /**
082   * Returns the set of store file paths successfully read by this scanner. Default implementation
083   * returns an empty set for non-file scanners (e.g. memstore).
084   */
085  @Override
086  public Set<Path> getFilesRead() {
087    return Collections.emptySet();
088  }
089
090  @Override
091  public ExtendedCell getNextIndexedKey() {
092    return null;
093  }
094
095  @Override
096  public void shipped() throws IOException {
097    // do nothing
098  }
099}