com.mellanox.r4h.client.HdfsDataInputStream.java Source code

Introduction

Here is the source code for com.mellanox.r4h.client.HdfsDataInputStream.java

Source

/**
 * 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.
 */
package com.mellanox.r4h.client;

import java.io.InputStream;
import java.io.IOException;
import java.util.List;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.crypto.CryptoInputStream;
import com.mellanox.r4h.DFSInputStream;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;

import com.google.common.base.Preconditions;

/**
 * The Hdfs implementation of {@link FSDataInputStream}.
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HdfsDataInputStream extends FSDataInputStream {
    public HdfsDataInputStream(DFSInputStream in) throws IOException {
        super(in);
    }

    public HdfsDataInputStream(CryptoInputStream in) throws IOException {
        super(in);
        Preconditions.checkArgument(in.getWrappedStream() instanceof DFSInputStream,
                "CryptoInputStream should wrap a DFSInputStream");
    }

    private DFSInputStream getDFSInputStream() {
        if (in instanceof CryptoInputStream) {
            return (DFSInputStream) ((CryptoInputStream) in).getWrappedStream();
        }
        return (DFSInputStream) in;
    }

    /**
     * Get a reference to the wrapped output stream. We always want to return the
     * actual underlying InputStream, even when we're using a CryptoStream. e.g.
     * in the delegated methods below.
     * 
     * @return the underlying output stream
     */
    public InputStream getWrappedStream() {
        return in;
    }

    /**
     * Get the datanode from which the stream is currently reading.
     */
    public DatanodeInfo getCurrentDatanode() {
        return getDFSInputStream().getCurrentDatanode();
    }

    /**
     * Get the block containing the target position.
     */
    public ExtendedBlock getCurrentBlock() {
        return getDFSInputStream().getCurrentBlock();
    }

    /**
     * Get the collection of blocks that has already been located.
     */
    public synchronized List<LocatedBlock> getAllBlocks() throws IOException {
        return getDFSInputStream().getAllBlocks();
    }

    /**
     * Get the visible length of the file. It will include the length of the last
     * block even if that is in UnderConstruction state.
     * 
     * @return The visible length of the file.
     */
    public long getVisibleLength() throws IOException {
        return getDFSInputStream().getFileLength();
    }

    /**
     * Get statistics about the reads which this DFSInputStream has done.
     * Note that because HdfsDataInputStream is buffered, these stats may
     * be higher than you would expect just by adding up the number of
     * bytes read through HdfsDataInputStream.
     */
    public synchronized DFSInputStream.ReadStatistics getReadStatistics() {
        return getDFSInputStream().getReadStatistics();
    }
}