org.apache.flume.serialization
Class ResettableFileInputStream

java.lang.Object
  org.apache.flume.serialization.ResettableInputStream
      org.apache.flume.serialization.ResettableFileInputStream

All Implemented Interfaces:

Closeable, LengthMeasurable, RemoteMarkable, Resettable, Seekable

@InterfaceAudience.Private
@InterfaceStability.Evolving
public class ResettableFileInputStream
extends ResettableInputStream
implements RemoteMarkable, LengthMeasurable

This class makes the following assumptions:

1. The underlying file is not changing while it is being read

The ability to reset() is dependent on the underlying PositionTracker instance's durability semantics.

Field Summary

static int

DEFAULT_BUF_SIZE

Constructor Summary

ResettableFileInputStream(File file, PositionTracker tracker)

ResettableFileInputStream(File file, PositionTracker tracker, int bufSize, Charset charset)

Method Summary

void	close()
long	getMarkPosition() Return the saved mark position without moving the mark pointer.
long	length() returns the total length of the stream or file
void	mark() Marks the current position in this input stream.
void	markPosition(long position) Indicate that the specified position should be returned to in the case of Resettable.reset() being called.
int	read() Read a single byte of data from the stream.
int	read(byte[] b, int off, int len) Read multiple bytes of data from the stream.
int	readChar() Read a single character.
void	reset() Reset stream position to that set by ResettableInputStream.mark()
void	seek(long newPos) Seek to the specified byte position in the stream.
long	tell() Tell the current byte position.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUF_SIZE

public static final int DEFAULT_BUF_SIZE

See Also:

Constant Field Values

Constructor Detail

ResettableFileInputStream

public ResettableFileInputStream(File file,
                                 PositionTracker tracker)
                          throws IOException

Parameters:

file - File to read

tracker - PositionTracker implementation to make offset position durable

Throws:

FileNotFoundException

IOException

ResettableFileInputStream

public ResettableFileInputStream(File file,
                                 PositionTracker tracker,
                                 int bufSize,
                                 Charset charset)
                          throws IOException

Parameters:

file - File to read

tracker - PositionTracker implementation to make offset position durable

bufSize - Size of the underlying buffer used for input

charset - Character set used for decoding text, as necessary

Throws:

FileNotFoundException

IOException

Method Detail

read

public int read()
         throws IOException

Description copied from class: ResettableInputStream

Read a single byte of data from the stream.

Specified by:

read in class ResettableInputStream

Returns:

the next byte of data, or -1 if the end of the stream has been reached.

Throws:

IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Description copied from class: ResettableInputStream

Read multiple bytes of data from the stream.

Specified by:

read in class ResettableInputStream

Parameters:

b - the buffer into which the data is read.

off - Offset into the array b at which the data is written.

len - the maximum number of bytes to read.

Returns:

the total number of bytes read into the buffer, or -1 if the end of the stream has been reached.

Throws:

IOException

readChar

public int readChar()
             throws IOException

Description copied from class: ResettableInputStream

Read a single character.

Note that this may lead to returning only one character in a 2-char surrogate pair sequence. When this happens, the underlying implementation should never persist a mark between two chars of a two-char surrogate pair sequence.

Specified by:

readChar in class ResettableInputStream

Returns:

The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached

Throws:

IOException

mark

public void mark()
          throws IOException

Description copied from class: ResettableInputStream

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

Marking a closed stream should not have any effect on the stream.

Specified by:

mark in interface Resettable

Specified by:

mark in class ResettableInputStream

Throws:

IOException - If there is an error while setting the mark position.

See Also:

InputStream.mark(int), InputStream.reset()

markPosition

public void markPosition(long position)
                  throws IOException

Description copied from interface: RemoteMarkable

Indicate that the specified position should be returned to in the case of Resettable.reset() being called.

Specified by:

markPosition in interface RemoteMarkable

Throws:

IOException

getMarkPosition

public long getMarkPosition()
                     throws IOException

Description copied from interface: RemoteMarkable

Return the saved mark position without moving the mark pointer.

Specified by:

getMarkPosition in interface RemoteMarkable

Throws:

IOException

reset

public void reset()
           throws IOException

Description copied from class: ResettableInputStream

Reset stream position to that set by ResettableInputStream.mark()

Specified by:

reset in interface Resettable

Specified by:

reset in class ResettableInputStream

Throws:

IOException

length

public long length()
            throws IOException

Description copied from interface: LengthMeasurable

returns the total length of the stream or file

Specified by:

length in interface LengthMeasurable

Throws:

IOException

tell

public long tell()
          throws IOException

Description copied from class: ResettableInputStream

Tell the current byte position.

Specified by:

tell in interface Seekable

Specified by:

tell in class ResettableInputStream

Returns:

the current absolute byte position in the stream

Throws:

IOException

seek

public void seek(long newPos)
          throws IOException

Description copied from class: ResettableInputStream

Seek to the specified byte position in the stream.

Specified by:

seek in interface Seekable

Specified by:

seek in class ResettableInputStream

Parameters:

newPos - Absolute byte offset to seek to

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in class ResettableInputStream

Throws:

IOException