org.apache.river.mercury

Class LogInputStream

java.lang.Object

java.io.InputStream

org.apache.river.mercury.LogInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, LogStream

class LogInputStream
extends InputStream
implements LogStream

This class implements the interface for interacting with input log streams. It extends java.util.InputStream and overrides its methods in order to provide buffered input as well as byte offset tracking, which is useful during recovery situations.

Since:

1.1

Author:

Sun Microsystems, Inc.

Field Summary

Fields

Modifier and Type	Field and Description
private byte[]	buf byte array buffer to hold read data
private static int	BUFSIZE Holds value of the internal buffer size to allocate
private int	count count of available bytes in the read buffer
private FileInputStream	in Underlying input stream from which bytes are read
private StreamKey	key Associated key for this stream object
private long	offset cumulative index/offset into this stream
private int	pos index/offset into the read buffer for the next set of bytes to read

Constructor Summary

Constructors

Constructor and Description
LogInputStream(File file, StreamKey key) Simple constructor that accepts a File and StreamKey arguments.

Method Summary

Modifier and Type	Method and Description
int	available()
void	close() Closes this LogStream object and releases any associated resources.
Object	getKey() Returns the associated key for this LogStream.
long	getOffset() Returns the current "read" offset into this stream object.
int	read()
int	read(byte[] b)
int	read(byte[] b, int off, int len)
private void	refill() Refills the internal buffer with any available bytes.
long	skip(long n)

Methods inherited from class java.io.InputStream

mark, markSupported, reset

Methods inherited from class java.lang.Object

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

Field Detail

BUFSIZE

private static final int BUFSIZE

Holds value of the internal buffer size to allocate

See Also:

Constant Field Values

buf

private byte[] buf

byte array buffer to hold read data

count

private int count

count of available bytes in the read buffer

pos

private int pos

index/offset into the read buffer for the next set of bytes to read

offset

private long offset

cumulative index/offset into this stream

in

private FileInputStream in

Underlying input stream from which bytes are read

key

private StreamKey key

Associated key for this stream object

Constructor Detail

LogInputStream

public LogInputStream(File file,
                      StreamKey key)
               throws FileNotFoundException

Simple constructor that accepts a File and StreamKey arguments. The File and StreamKey arguments are assigned to their respective internal fields.

Parameters:

file - the File to used

key - the associated key for this object

Throws:

IllegalArgumentException - if either the file or key arguments are null.

FileNotFoundException - if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.

Method Detail

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

read

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

Overrides:

read in class InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

available

public int available()
              throws IOException

Overrides:

available in class InputStream

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: LogStream

Closes this LogStream object and releases any associated resources.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface LogStream

Overrides:

close in class InputStream

Throws:

IOException - if an I/O error occured while attempting to close the LogStream.

getOffset

public long getOffset()

Returns the current "read" offset into this stream object.

refill

private void refill()
             throws IOException

Refills the internal buffer with any available bytes. This method will block until either bytes have been read, or no more bytes can be read.

Throws:

IOException

getKey

public Object getKey()

Description copied from interface: LogStream

Returns the associated key for this LogStream. This key is intended to be used as the key in a java.util.Collection.

Specified by:

getKey in interface LogStream