OWFileInputStream Class Reference

A OWFileInputStream obtains input bytes from a file in a 1-Wire Filesystem. More...

Inherits java::io::InputStream.

List of all members.

Public Member Functions
	OWFileInputStream (OneWireContainer owd, String name) throws OWFileNotFoundException
	Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the Filesystem.
	OWFileInputStream (OneWireContainer[] owd, String name) throws OWFileNotFoundException
	Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the Filesystem.
	OWFileInputStream (OWFile file) throws OWFileNotFoundException
	Creates a OWFileInputStream by opening a connection to an actual file, the file named by the File object file in the Filesystem.
	OWFileInputStream (OWFileDescriptor fdObj)
	Creates a OWFileInputStream by using the file descriptor fdObj, which represents an existing connection to an actual file in the Filesystem.
int	read () throws IOException
	Reads a byte of data from this input stream.
int	read (byte b[]) throws IOException
	Reads up to b.length bytes of data from this input stream into an array of bytes.
int	read (byte b[], int off, int len) throws IOException
	Reads up to len bytes of data from this input stream into an array of bytes.
long	skip (long n) throws IOException
	Skips over and discards n bytes of data from the input stream.
int	available () throws IOException
	Returns the number of bytes that can be read from this file input stream without blocking.
void	close () throws IOException
	Closes this file input stream and releases any system resources associated with the stream.
final OWFileDescriptor	getFD () throws IOException
	Returns the OWFileDescriptor object that represents the connection to the actual file in the Filesystem being used by this FileInputStream.
void	finalize () throws IOException
	Ensures that the close method of this file input stream is called when there are no more references to it.
void	mark (int readlimit)
	Marks the current position in this input stream.
void	reset () throws IOException
	Repositions this stream to the position at the time the mark method was last called on this input stream.
boolean	markSupported ()
	Tests if this input stream supports the mark and reset methods.

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Detailed Description

A OWFileInputStream obtains input bytes from a file in a 1-Wire Filesystem.

What files are available depends on the 1-Wire device.

Note that the 1-Wire File system can reside across multiple 1-Wire devices. In this case only one of the devices need be supplied to the constructor. Each device in a multi-device file system contains information to reacquire the entire list.

File and directory name limitations

• File/directory names limited to 4 characters not including extension
• File/directory names are not case sensitive and will be automatically changed to all-CAPS
• Only files can have extensions
• Extensions are numberical in the range 0 to 125
• Extensions 100 to 125 are special purpose and not yet implemented or allowed
• Files can have the read-only attribute
• Directories can have the hidden attribute
• It is recommended to limit directory depth to 10 levels to accomodate legacy implementations

Usage

Example

Read from a 1-Wire file on device 'owd':

 
   // get an input stream to the 1-Wire file
   OWFileInputStream instream = new OWFileInputStream(owd, "DEMO.0");

   // read some data
   byte[] data = new byte[2000];
   int len = instream.read(data);

   // close the stream to release system resources
   instream.close();

Author:

DS

Version:

0.01, 1 June 2001

See also:

com.dalsemi.onewire.application.file.OWFile

com.dalsemi.onewire.application.file.OWFileDescriptor

com.dalsemi.onewire.application.file.OWFileOutputStream

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Constructor & Destructor Documentation

OWFileInputStream	(	OneWireContainer	owd,
		String	name
	)		throws OWFileNotFoundException

Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the Filesystem.

A new OWFileDescriptor 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 FileNotFoundException is thrown.

Parameters:

owd	OneWireContainer that this Filesystem resides on
name	the system-dependent file name.

Exceptions:

FileNotFoundException

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

OWFileInputStream	(	OneWireContainer[]	owd,
		String	name
	)		throws OWFileNotFoundException

Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the Filesystem.

A new OWFileDescriptor 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 FileNotFoundException is thrown.

Parameters:

owd	array of OneWireContainers that this Filesystem resides on
name	the system-dependent file name.

Exceptions:

FileNotFoundException

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

OWFileInputStream

(

OWFile

file

)

throws OWFileNotFoundException

Creates a OWFileInputStream by opening a connection to an actual file, the file named by the File object file in the Filesystem.

A new OWFileDescriptor object is created to represent this file connection.

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 FileNotFoundException is thrown.

Parameters:

file	the file to be opened for reading.

Exceptions:

FileNotFoundException

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:

com.dalsemi.onewire.application.file.OWFile.getPath()

OWFileInputStream

(

OWFileDescriptor

fdObj

)

Creates a OWFileInputStream by using the file descriptor fdObj, which represents an existing connection to an actual file in the Filesystem.

If fdObj is null then a NullPointerException is thrown.

Parameters:

fdObj

the file descriptor to be opened for reading.

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Member Function Documentation

int available

(

)

throws IOException

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

Returns:

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

Exceptions:

IOException

if an I/O error occurs.

void close

(

)

throws IOException

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

Exceptions:

IOException

if an I/O error occurs.

void finalize

(

)

throws IOException

Ensures that the close method of this file input stream is called when there are no more references to it.

Exceptions:

IOException

if an I/O error occurs.

See also:

com.dalsemi.onewire.application.file.OWFileInputStream.close()

final OWFileDescriptor getFD

(

)

throws IOException

Returns the OWFileDescriptor object that represents the connection to the actual file in the Filesystem being used by this FileInputStream.

Returns:

the file descriptor object associated with this stream.

Exceptions:

IOException

if an I/O error occurs.

See also:

com.dalsemi.onewire.application.file.OWFileDescriptor

void mark

(

int

readlimit

)

Marks the current position in this input stream.

A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

The readlimit arguments tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

The general contract of mark is that, if the method markSupported returns true, the stream somehow remembers all the bytes read after the call to mark and stands ready to supply those same bytes again if and whenever the method reset is called. However, the stream is not required to remember any data at all if more than readlimit bytes are read from the stream before reset is called.

The mark method of InputStream does nothing.

Parameters:

readlimit

the maximum limit of bytes that can be read before the mark position becomes invalid.

See also:

java.io.InputStream.reset()

boolean markSupported

(

)

Tests if this input stream supports the mark and reset methods.

The markSupported method of InputStream returns false.

Returns:

true if this true type supports the mark and reset method; false otherwise.

See also:

java.io.InputStream.mark(int)

java.io.InputStream.reset()

int read

(

byte

b[]

)

throws IOException

Reads up to b.length bytes of data from this input stream into an array of bytes.

This method blocks until some input is available.

Parameters:

b	the buffer into which the data is read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.

Exceptions:

IOException

if an I/O error occurs.

int read

(

)

throws IOException

Reads a byte of data from this input stream.

This method blocks if no input is yet available.

Returns:

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

Exceptions:

IOException

if an I/O error occurs.

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

Reads up to len bytes of data from this input stream into an array of bytes.

This method blocks until some input is available.

Parameters:

b	the buffer into which the data is read.
off	the start offset of the data.
len	the maximum number of bytes read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.

Exceptions:

IOException

if an I/O error occurs.

void reset

(

)

throws IOException

Repositions this stream to the position at the time the mark method was last called on this input stream.

The general contract of reset is:

• If the method markSupported returns true, then:

  • If the method mark has not been called since the stream was created, or the number of bytes read from the stream since mark was last called is larger than the argument to mark at that last call, then an IOException might be thrown.

  • If such an IOException is not thrown, then the stream is reset to a state such that all the bytes read since the most recent call to mark (or since the start of the file, if mark has not been called) will be resupplied to subsequent callers of the read method, followed by any bytes that otherwise would have been the next input data as of the time of the call to reset.

• If the method markSupported returns false, then:

  • The call to reset may throw an IOException.

  • If an IOException is not thrown, then the stream is reset to a fixed state that depends on the particular type of the input stream and how it was created. The bytes that will be supplied to subsequent callers of the read method depend on the particular type of the input stream.

The method reset for class InputStream does nothing and always throws an IOException.

Exceptions:

IOException

if this stream has not been marked or if the mark has been invalidated.

See also:

java.io.InputStream.mark(int)

java.io.IOException

long skip

(

long

n

)

throws 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.

Parameters:

n	the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Exceptions:

IOException

if an I/O error occurs.

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The documentation for this class was generated from the following file:

• OWFileInputStream.java