edu.sdsc.grid.io.srb
Class SRBFileInputStream

java.lang.Object
  java.io.InputStream
      edu.sdsc.grid.io.GeneralFileInputStream
          edu.sdsc.grid.io.RemoteFileInputStream
              edu.sdsc.grid.io.srb.SRBFileInputStream

All Implemented Interfaces:

java.io.Closeable

public class SRBFileInputStream
extends RemoteFileInputStream

A SRBFileInputStream obtains input bytes from a file in a SRB file system. What files are available depends on the host environment.

SRBFileInputStream is meant for reading streams of raw bytes such as image data.

Since:

JARGON1.4

Field Summary

protected SRBFileSystem

fileSystem Holds the server connection used by this stream.

Fields inherited from class edu.sdsc.grid.io.GeneralFileInputStream

fd

Constructor Summary

SRBFileInputStream(SRBFile file)
Creates a SRBFileInputStream by opening a connection to an actual file, the file named by the File object file in the file system.

SRBFileInputStream(SRBFileSystem fileSystem, java.lang.String name)
Creates a SRBFileInputStream by opening a connection to an actual file, the file named by the path name name in the file system.

Method Summary

int	available() Returns the number of bytes that can be read from this file input stream without blocking.
void	close() Closes this file input stream and releases any system resources associated with the stream.
GeneralFileSystem	getFileSystem() Returns the srb file system object.
protected void	open(GeneralFile file) Opens the given file for use by this stream.
int	read() Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
protected void	setFileSystem(GeneralFileSystem fileSystem) Sets the SRB server used of this SRBRandomAccessFile object.
long	skip(long n) Skips over and discards n bytes of data from the input stream.
java.lang.String	toString()

Methods inherited from class edu.sdsc.grid.io.GeneralFileInputStream

finalize, read

Methods inherited from class java.io.InputStream

mark, markSupported, reset

Methods inherited from class java.lang.Object

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

Field Detail

fileSystem

protected SRBFileSystem fileSystem

Holds the server connection used by this stream.

Constructor Detail

SRBFileInputStream

public SRBFileInputStream(SRBFileSystem fileSystem,
                          java.lang.String name)
                   throws java.io.IOException

Creates a SRBFileInputStream by opening a connection to an actual file, the file named by the path name name in the file system. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkRead method is called with the name argument as its argument.

If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a IOException is thrown.

Parameters:

name - the system-dependent file name.

Throws:

java.io.IOException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.

SRBFileInputStream

public SRBFileInputStream(SRBFile file)
                   throws java.io.IOException

Creates a SRBFileInputStream by opening a connection to an actual file, the file named by the File object file in the file system. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkRead method is called with the path represented by the file argument as its argument.

If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a IOException is thrown.

Parameters:

file - the file to be opened for reading.

Throws:

java.io.IOException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.

See Also:

File.getPath()

Method Detail

setFileSystem

protected void setFileSystem(GeneralFileSystem fileSystem)
                      throws java.lang.IllegalArgumentException,
                             java.lang.ClassCastException

Sets the SRB server used of this SRBRandomAccessFile object.

Parameters:

fleServer - The SRB server to be used.

Throws:

java.lang.IllegalArgumentException - - if the argument is null.

java.lang.ClassCastException - - if the argument is not a SRBFileSystem object.

getFileSystem

public GeneralFileSystem getFileSystem()

Returns the srb file system object.

Returns:

RemoteFileSystem

Throws:

java.lang.NullPointerException - if fileSystem is null.

open

protected void open(GeneralFile file)
             throws java.io.IOException

Opens the given file for use by this stream.

Specified by:

open in class GeneralFileInputStream

Parameters:

file - the file to be opened.

Throws:

java.io.IOException - if an I/O error occurs.

read

public int read()
         throws java.io.IOException

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Specified by:

read in class GeneralFileInputStream

Returns:

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

Throws:

java.io.IOException - if an I/O error occurs.

read

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

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If b is null, a NullPointerException is thrown.

If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected.

If the first byte cannot be read for any reason other than end of file, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

The read(b, off, len) method for class InputStream simply calls the method read() repeatedly. If the first such call results in an IOException, that exception is returned from the call to the read(b, off, len) method. If any subsequent call to read() results in a IOException, the exception is caught and treated as if it were end of file; the bytes read up to that point are stored into b and the number of bytes read before the exception occurred is returned. Subclasses are encouraged to provide a more efficient implementation of this method.

Specified by:

read in class GeneralFileInputStream

Parameters:

b - the buffer into which the data is read.

off - the start offset in 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 there is no more data because the end of the stream has been reached.

Throws:

java.io.IOException - if an I/O error occurs.

java.lang.NullPointerException - if b is null.

See Also:

InputStream.read()

skip

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

Skips over and discards n bytes of data from the input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number of bytes skipped is returned.

Specified by:

skip in class GeneralFileInputStream

Parameters:

n - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Throws:

java.io.IOException - if an I/O error occurs.

available

public int available()
              throws java.io.IOException

Returns the number of bytes that can be read from this file input stream without blocking.

Specified by:

available in class GeneralFileInputStream

Returns:

the number of bytes that can be read from this file input stream without blocking.

Throws:

java.io.IOException - if an I/O error occurs.

close

public void close()
           throws java.io.IOException

Closes this file input stream and releases any system resources associated with the stream.

If this stream has an associated channel then the channel is closed as well.

Specified by:

close in interface java.io.Closeable

Specified by:

close in class GeneralFileInputStream

Throws:

java.io.IOException - if an I/O error occurs.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object