eve.io

Class NullInputStream

java.lang.Object

java.io.InputStream

eve.io.NullInputStream

public class NullInputStream
extends InputStream

Author:

Michael L Brereton

Constructor Summary

Constructors

Constructor and Description
NullInputStream(boolean returnError) Create a NullInputStream that will either always throw an IOException or will always return EOF.

Method Summary

Modifier and Type	Method and Description
void	close() This method closes the stream.
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.
long	skip(long toSkip) This method skips the specified number of bytes in the stream.

Methods inherited from class java.io.InputStream

available, finalize, hashCode, mark, markSupported, read, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

NullInputStream

public NullInputStream(boolean returnError)

Create a NullInputStream that will either always throw an IOException or will always return EOF.

Parameters:

returnError - if this is true any attempted read will throw an IOException, otherwise it will return EOF.

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.

skip

public long skip(long toSkip)
          throws IOException

Description copied from class: InputStream

This method skips the specified number of bytes in the stream. It returns the actual number of bytes skipped, which may be less than the requested amount.

This method reads and discards bytes into a byte array until the specified number of bytes were skipped or until either the end of stream is reached or a read attempt returns a short count. Subclasses can override this metho to provide a more efficient implementation where one exists.

Overrides:

skip in class InputStream

Parameters:

toSkip - The requested number of bytes to skip

Returns:

The actual number of bytes skipped.

Throws:

IOException - If an error occurs

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