com.continuent.tungsten.common.io
Class BufferedFileDataInput

java.lang.Object
  com.continuent.tungsten.common.io.BufferedFileDataInput

public class BufferedFileDataInput
extends java.lang.Object

Merges the capabilities of the following stream classes into a single class: FileInputStream, BufferedInputStream, and DataInputStream. This allows us to manage buffered data reads from files efficiently.

Author:

Robert Hodges

Constructor Summary

BufferedFileDataInput(java.io.File file)
Creates instance with default buffer size.

BufferedFileDataInput(java.io.File file, int size)
Creates instance positioned on start of file.

Method Summary

long	available() Query the stream directly for the number of bytes available for immediate read without blocking.
void	close() Close and release all resources.
long	getOffset() Returns the current offset position.
void	mark(int readLimit) Mark stream to read up to limit.
byte	readByte() Reads a single byte.
void	readFully(byte[] bytes) Reads a full byte array completely.
void	readFully(byte[] bytes, int start, int len) Reads a full byte array completely.
int	readInt() Read a single integer.
long	readLong() Reads a single long.
short	readShort() Reads a single short.
void	reset() Reset stream back to last mark.
void	seek(long seekBytes) Seek to a specific offset in the file.
long	skip(long bytes) Skip requested number of bytes.
java.lang.String	toString() Print contents of the reader.
long	waitAvailable(int requested, int waitMillis) Waits for a specified number of bytes to be available for a non-blocking read.

Methods inherited from class java.lang.Object

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

Constructor Detail

BufferedFileDataInput

public BufferedFileDataInput(java.io.File file,
                             int size)
                      throws java.io.FileNotFoundException,
                             java.io.IOException,
                             java.lang.InterruptedException

Creates instance positioned on start of file.

Parameters:

file - File from which to read

size - Size of buffer for buffered I/O

Throws:

java.io.FileNotFoundException

java.io.IOException

java.lang.InterruptedException

BufferedFileDataInput

public BufferedFileDataInput(java.io.File file)
                      throws java.io.FileNotFoundException,
                             java.io.IOException,
                             java.lang.InterruptedException

Creates instance with default buffer size.

Throws:

java.io.FileNotFoundException

java.io.IOException

java.lang.InterruptedException

Method Detail

getOffset

public long getOffset()

Returns the current offset position.

available

public long available()
               throws java.io.IOException,
                      java.lang.InterruptedException

Query the stream directly for the number of bytes available for immediate read without blocking. This operation may result in a file system metadata call. To find out if a specific number of bytes are known to be available use waitForAvailable().

Returns:

Number of bytes available for non-blocking read

Throws:

java.io.IOException

java.lang.InterruptedException

waitAvailable

public long waitAvailable(int requested,
                          int waitMillis)
                   throws java.io.IOException,
                          java.lang.InterruptedException

Waits for a specified number of bytes to be available for a non-blocking read.

Parameters:

requested - Number of bytes to read

waitMillis - Milliseconds to wait before timeout

Returns:

Number of bytes available for non-blocking read

Throws:

java.io.IOException - Thrown if there is a problem checking for available bytes

java.lang.InterruptedException - Thrown if we are interrupted while waiting

mark

public void mark(int readLimit)

Mark stream to read up to limit.

Parameters:

readLimit - Number of bytes that may be read before resetting

reset

public void reset()
           throws java.io.IOException,
                  java.lang.InterruptedException

Reset stream back to last mark.

Throws:

java.io.IOException - Thrown if mark has been invalidated or not set

java.lang.InterruptedException - Thrown if we are interrupted

skip

public long skip(long bytes)
          throws java.io.IOException

Skip requested number of bytes.

Parameters:

bytes - Number of bytes to skip

Returns:

Number of bytes actually skipped

Throws:

java.io.IOException - Thrown if seek not supported or other error

seek

public void seek(long seekBytes)
          throws java.io.FileNotFoundException,
                 java.io.IOException,
                 java.lang.InterruptedException

Seek to a specific offset in the file.

Parameters:

seekBytes - Number of bytes from start of file

Throws:

java.io.IOException - Thrown if offset cannot be found

java.io.FileNotFoundException - Thrown if file is not found

java.lang.InterruptedException - Thrown if thread is interrupted

readByte

public byte readByte()
              throws java.io.IOException

Reads a single byte.

Throws:

java.io.IOException

readShort

public short readShort()
                throws java.io.IOException

Reads a single short.

Throws:

java.io.IOException

readInt

public int readInt()
            throws java.io.IOException

Read a single integer.

Throws:

java.io.IOException

readLong

public long readLong()
              throws java.io.IOException

Reads a single long.

Throws:

java.io.IOException

readFully

public void readFully(byte[] bytes)
               throws java.io.IOException

Reads a full byte array completely.

Throws:

java.io.IOException - Thrown if full byte array cannot be read

readFully

public void readFully(byte[] bytes,
                      int start,
                      int len)
               throws java.io.IOException

Reads a full byte array completely.

Parameters:

bytes - Buffer into which to read

start - Starting byte position

len - Number of bytes to read

Throws:

java.io.IOException - Thrown if data cannot be read

close

public void close()

Close and release all resources.

toString

public java.lang.String toString()

Print contents of the reader.

Overrides:

toString in class java.lang.Object