001/**
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase.io.hfile;
020
021import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkArgument;
022import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkNotNull;
023import java.io.IOException;
024import org.apache.hadoop.fs.FileSystem;
025import org.apache.hadoop.fs.Path;
026import org.apache.hadoop.hbase.fs.HFileSystem;
027import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
028import org.apache.hadoop.hbase.io.hfile.ReaderContext.ReaderType;
029import org.apache.yetus.audience.InterfaceAudience;
030import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
031
032/**
033 * A builder that helps in building up the ReaderContext
034 */
035@InterfaceAudience.Private
036public class ReaderContextBuilder {
037  private Path filePath;
038  private FSDataInputStreamWrapper fsdis;
039  private long fileSize;
040  private HFileSystem hfs;
041  private boolean primaryReplicaReader = true;
042  private ReaderType type = ReaderType.PREAD;
043
044  public ReaderContextBuilder() {}
045
046  public ReaderContextBuilder withFilePath(Path filePath) {
047    this.filePath = filePath;
048    return this;
049  }
050
051  public ReaderContextBuilder withFileSize(long fileSize) {
052    this.fileSize = fileSize;
053    return this;
054  }
055
056  public ReaderContextBuilder withInputStreamWrapper(FSDataInputStreamWrapper fsdis) {
057    this.fsdis = fsdis;
058    return this;
059  }
060
061  public ReaderContextBuilder withFileSystem(HFileSystem hfs) {
062    this.hfs = hfs;
063    return this;
064  }
065
066  public ReaderContextBuilder withFileSystem(FileSystem fs) {
067    if (!(fs instanceof HFileSystem)) {
068      this.hfs = new HFileSystem(fs);
069    } else {
070      this.hfs = (HFileSystem) fs;
071    }
072    return this;
073  }
074
075  public ReaderContextBuilder withPrimaryReplicaReader(boolean primaryReplicaReader) {
076    this.primaryReplicaReader = primaryReplicaReader;
077    return this;
078  }
079
080  public ReaderContextBuilder withReaderType(ReaderType type) {
081    this.type = type;
082    return this;
083  }
084
085  @VisibleForTesting
086  public ReaderContextBuilder withFileSystemAndPath(FileSystem fs, Path filePath)
087      throws IOException {
088    this.withFileSystem(fs)
089        .withFilePath(filePath)
090        .withFileSize(fs.getFileStatus(filePath).getLen())
091        .withInputStreamWrapper(new FSDataInputStreamWrapper(fs, filePath));
092    return this;
093  }
094
095  public ReaderContext build() {
096    validateFields();
097    return new ReaderContext(filePath, fsdis, fileSize, hfs, primaryReplicaReader, type);
098  }
099
100  private void validateFields() throws IllegalArgumentException {
101    checkNotNull(filePath, "Illegal ReaderContext, no filePath specified.");
102    checkNotNull(fsdis, "Illegal ReaderContext, no StreamWrapper specified.");
103    checkNotNull(hfs, "Illegal ReaderContext, no HFileSystem specified.");
104    checkArgument(fileSize > 0L, "Illegal ReaderContext, fileSize <= 0");
105  }
106}