org.apache.hadoop.hbase.io

Class FSDataInputStreamWrapper

java.lang.Object

org.apache.hadoop.hbase.io.FSDataInputStreamWrapper

public class FSDataInputStreamWrapper
extends Object

Wrapper for input stream(s) that takes care of the interaction of FS and HBase checksums, as well as closing streams. Initialization is not thread-safe, but normal operation is; see method comments.

Constructor Summary

Constructors

Constructor and Description
FSDataInputStreamWrapper(FileSystem fs, FileLink link)
FSDataInputStreamWrapper(FileSystem fs, Path path)
FSDataInputStreamWrapper(FSDataInputStream fsdis) For use in tests.
FSDataInputStreamWrapper(FSDataInputStream fsdis, FSDataInputStream noChecksum) For use in tests.

Method Summary

Modifier and Type	Method and Description
void	checksumOk() Report that checksum was ok, so we may ponder going back to HBase checksum.
void	close() Close stream(s) if necessary.
FSDataInputStream	fallbackToFsChecksum(int offCount) Read from non-checksum stream failed, fall back to FS checksum.
HFileSystem	getHfs()
FSDataInputStream	getStream(boolean useHBaseChecksum) Get the stream to use.
void	prepareForBlockReader(boolean forceNoHBaseChecksum) Prepares the streams for block reader.
boolean	shouldUseHBaseChecksum()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FSDataInputStreamWrapper

public FSDataInputStreamWrapper(FileSystem fs,
                                Path path)
                         throws IOException

Throws:

IOException

FSDataInputStreamWrapper

public FSDataInputStreamWrapper(FileSystem fs,
                                FileLink link)
                         throws IOException

Throws:

IOException

FSDataInputStreamWrapper

public FSDataInputStreamWrapper(FSDataInputStream fsdis)

For use in tests.

FSDataInputStreamWrapper

public FSDataInputStreamWrapper(FSDataInputStream fsdis,
                                FSDataInputStream noChecksum)

For use in tests.

Method Detail

prepareForBlockReader

public void prepareForBlockReader(boolean forceNoHBaseChecksum)
                           throws IOException

Prepares the streams for block reader. NOT THREAD SAFE. Must be called once, after any reads finish and before any other reads start (what happens in reality is we read the tail, then call this based on what's in the tail, then read blocks).

Parameters:

forceNoHBaseChecksum - Force not using HBase checksum.

Throws:

IOException

shouldUseHBaseChecksum

public boolean shouldUseHBaseChecksum()

Returns:

Whether we are presently using HBase checksum.

getStream

public FSDataInputStream getStream(boolean useHBaseChecksum)

Get the stream to use. Thread-safe.

Parameters:

useHBaseChecksum - must be the value that shouldUseHBaseChecksum has returned at some point in the past, otherwise the result is undefined.

fallbackToFsChecksum

public FSDataInputStream fallbackToFsChecksum(int offCount)
                                       throws IOException

Read from non-checksum stream failed, fall back to FS checksum. Thread-safe.

Parameters:

offCount - For how many checksumOk calls to turn off the HBase checksum.

Throws:

IOException

checksumOk

public void checksumOk()

Report that checksum was ok, so we may ponder going back to HBase checksum.

close

public void close()
           throws IOException

Close stream(s) if necessary.

Throws:

IOException

getHfs

public HFileSystem getHfs()