eve.io

Class FileRandomStream

java.lang.Object

java.io.InputStream

eve.io.RandomStream

eve.io.FileRandomStream

public class FileRandomStream
extends RandomStream

Author:

Michael L Brereton

Field Summary

Fields inherited from class eve.io.RandomStream

READ_ONLY, READ_WRITE

Constructor Summary

Constructors

Constructor and Description
FileRandomStream(File file, String mode)
FileRandomStream(File file, String mode)
FileRandomStream(String filePath, String mode)

Method Summary

Modifier and Type	Method and Description
boolean	canSetLength() Return if this Stream has the capability to set the stream length in Read/Write mode.
void	close() This method closes the stream.
void	flush() This method forces any data that may have been buffered to be written to the underlying output device.
long	getLength() Return the full length of the Stream.
long	getPosition() Return the current read/write stream pointer.
int	read() This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255.
int	read(byte[] dest, int offset, int count) This method read bytes from a stream and stores them into a caller supplied buffer.
void	setLength(long length) Attempt to set the length of the stream if this is supported.
void	setPosition(long newPosition) Set the Stream position.
static RandomStream	toRandomStream(RandomAccessFile raf, String mode) Convert a RandomAccessFile to a RandomStream using the most efficient method.
void	write(byte[] src, int offset, int count) This method writes len bytes from the specified array b starting at index off into the array.
void	write(int ch) This method writes a single byte to the output stream.

Methods inherited from class eve.io.RandomStream

isOpenForWriting, isReadWrite, mark, markSupported, reset, setMode, skip, throwCantWrite, toOutputStream, validateMode, write

Methods inherited from class java.io.InputStream

available, finalize, hashCode, read

Methods inherited from class java.lang.Object

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

Constructor Detail

FileRandomStream

public FileRandomStream(String filePath,
                        String mode)
                 throws IllegalArgumentException,
                        FileNotFoundException

Parameters:

filePath -

mode - should be either "r" or "rw"

Throws:

IllegalArgumentException

FileNotFoundException

FileRandomStream

public FileRandomStream(File file,
                        String mode)
                 throws IllegalArgumentException,
                        FileNotFoundException

Parameters:

file -

mode - should be either "r" or "rw"

Throws:

IllegalArgumentException

FileNotFoundException

FileRandomStream

public FileRandomStream(File file,
                        String mode)
                 throws IllegalArgumentException,
                        FileNotFoundException

Parameters:

file -

mode - should be either "r" or "rw"

Throws:

IllegalArgumentException

FileNotFoundException

Method Detail

read

public int read()
         throws IOException

Description copied from class: InputStream

This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255. This method also will return -1 if the end of the stream has been reached.

This method will block until the byte can be read.

Overrides:

read in class InputStream

Returns:

The byte read or -1 if end of stream

Throws:

IOException - If an error occurs

read

public int read(byte[] dest,
                int offset,
                int count)
         throws IOException

Description copied from class: InputStream

This method read bytes from a stream and stores them into a caller supplied buffer. It starts storing the data at index off into the buffer and attempts to read len bytes. This method can return before reading the number of bytes requested. The actual number of bytes read is returned as an int. A -1 is returned to indicate the end of the stream.

This method will block until some data can be read.

This method operates by calling the single byte read() method in a loop until the desired number of bytes are read. The read loop stops short if the end of the stream is encountered or if an IOException is encountered on any read operation except the first. If the first attempt to read a bytes fails, the IOException is allowed to propagate upward. And subsequent IOException is caught and treated identically to an end of stream condition. Subclasses can (and should if possible) override this method to provide a more efficient implementation.

Overrides:

read in class InputStream

Parameters:

dest - The array into which the bytes read should be stored

offset - The offset into the array to start storing bytes

count - The requested number of bytes to read

Returns:

The actual number of bytes read, or -1 if end of stream.

Throws:

IOException - If an error occurs.

write

public void write(int ch)
           throws IOException

Description copied from class: RandomStream

This method writes a single byte to the output stream. The byte written is the low eight bits of the int passed as the argument.

Subclasses must provide an implementation of this method.

Overrides:

write in class RandomStream

Parameters:

ch - The byte to be written to the output stream, passed as the low eight bits of an int

Throws:

IOException - If an error occurs

write

public void write(byte[] src,
                  int offset,
                  int count)
           throws IOException

Description copied from class: RandomStream

This method writes len bytes from the specified array b starting at index off into the array.

This method in this class calls the single byte write() method in a loop until all bytes have been written. Subclasses should override this method if possible in order to provide a more efficent implementation.

Overrides:

write in class RandomStream

Parameters:

src - The array of bytes to write from

offset - The index into the array to start writing from

count - The number of bytes to write

Throws:

IOException - If an error occurs

getLength

public long getLength()
               throws IOException

Return the full length of the Stream.

Overrides:

getLength in class RandomStream

Throws:

IOException - if an IO error occured.

setLength

public void setLength(long length)
               throws IOException

Attempt to set the length of the stream if this is supported. This will truncate the stream or extend the stream to the requested length.

Overrides:

setLength in class RandomStream

Throws:

IOException - if the length cannot be set or if there was an error.

getPosition

public long getPosition()
                 throws IOException

Return the current read/write stream pointer.

Overrides:

getPosition in class RandomStream

Throws:

IOException - on error.

setPosition

public void setPosition(long newPosition)
                 throws IOException

Set the Stream position. This position actually set may be different if, say, the requested position is greater than the actual size of the Stream.

Overrides:

setPosition in class RandomStream

Parameters:

newPosition - the new position to set.

Throws:

IOException - on error.

canSetLength

public boolean canSetLength()

Return if this Stream has the capability to set the stream length in Read/Write mode.

Overrides:

canSetLength in class RandomStream

flush

public void flush()
           throws IOException

Description copied from class: RandomStream

This method forces any data that may have been buffered to be written to the underlying output device. Please note that the host environment might perform its own buffering unbeknowst to Java. In that case, a write made (for example, to a disk drive) might be cached in OS buffers instead of actually being written to disk.

This method in this class does nothing.

Overrides:

flush in class RandomStream

Throws:

IOException - If an error occurs

toRandomStream

public static RandomStream toRandomStream(RandomAccessFile raf,
                                          String mode)
                                   throws IllegalArgumentException,
                                          IOException

Convert a RandomAccessFile to a RandomStream using the most efficient method.

Parameters:

raf - the already open RandomAccessFile.

mode - the mode the RandomAccessFile is open for (either "r" or "rw").

Returns:

a RandomStream for reading from the open RandomAccessFile.

Throws:

IllegalArgumentException - if the mode is not "r" or "rw"

IOException - if the conversion could not be made for any reason.

close

public void close()
           throws IOException

Description copied from class: InputStream

This method closes the stream. Any futher attempts to read from the stream may generate an IOException

This method does nothing in this class, but subclasses may override this method in order to provide additional functionality.

Overrides:

close in class InputStream

Throws:

IOException - If an error occurs, which can only happen in a subclass