cc.solr.lucene.store.hdfs.HdfsFileWriter.java Source code

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Here is the source code for cc.solr.lucene.store.hdfs.HdfsFileWriter.java

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package cc.solr.lucene.store.hdfs;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.lucene.store.DataOutput;

public class HdfsFileWriter extends DataOutput {

    public static final int VERSION = -1;

    private FSDataOutputStream _outputStream;
    private HdfsMetaBlock _block;
    private List<HdfsMetaBlock> _blocks = new ArrayList<HdfsMetaBlock>();
    private long _length;
    private long _currentPosition;

    public HdfsFileWriter(FileSystem fileSystem, Path path) throws IOException {
        _outputStream = fileSystem.create(path);
        seek(0);
    }

    public long length() {
        return _length;
    }

    public void seek(long pos) throws IOException {
        if (_block != null) {
            _blocks.add(_block);
        }
        _block = new HdfsMetaBlock();
        _block.realPosition = _outputStream.getPos();
        _block.logicalPosition = pos;
        _currentPosition = pos;
    }

    public void close() throws IOException {
        if (_block != null) {
            _blocks.add(_block);
        }
        flushMetaBlocks();
        _outputStream.close();
    }

    private void flushMetaBlocks() throws IOException {
        for (HdfsMetaBlock block : _blocks) {
            block.write(_outputStream);
        }
        _outputStream.writeInt(_blocks.size());
        _outputStream.writeLong(length());
        _outputStream.writeInt(VERSION);
    }

    @Override
    public void writeByte(byte b) throws IOException {
        _outputStream.write(b & 0xFF);
        _block.length++;
        _currentPosition++;
        updateLength();
    }

    @Override
    public void writeBytes(byte[] b, int offset, int length) throws IOException {
        _outputStream.write(b, offset, length);
        _block.length += length;
        _currentPosition += length;
        updateLength();
    }

    private void updateLength() {
        if (_currentPosition > _length) {
            _length = _currentPosition;
        }
    }

    public long getPosition() {
        return _currentPosition;
    }
}