org.apache.hadoop.hdfs.client.HdfsDataInputStream Maven / Gradle / Ivy
/**
* 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 org.apache.hadoop.hdfs.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 org.apache.hadoop.hdfs.DFSInputStream;
import org.apache.hadoop.hdfs.ReadStatistics;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions;
/**
* The Hdfs implementation of {@link FSDataInputStream}.
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HdfsDataInputStream extends FSDataInputStream {
public HdfsDataInputStream(DFSInputStream in) {
super(in);
}
public HdfsDataInputStream(CryptoInputStream in) {
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 List 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() {
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 ReadStatistics getReadStatistics() {
return getDFSInputStream().getReadStatistics();
}
public void clearReadStatistics() {
getDFSInputStream().clearReadStatistics();
}
}