Class OWFileOutputStream
- All Implemented Interfaces:
Closeable
,Flushable
,AutoCloseable
OWFile
or to a OWFileDescriptor
. Whether or not a
file is available or may be created depends upon the underlying platform.
This platform allows a file to be opened for writing by only one
OWFileOutputStream (or other file-writing object) at a time. In such
situations the constructors in this class will fail if the file involved is
already open. The 1-Wire File system must be formatted before use. Use
OWFile:format to prepare a device or group of devices.
The 1-Wire device will only be written in the following situations
- use
getFD()
and call thesync()
method of theOWFileDescriptor
until aSyncFailedException
is NOT thrown - if the device runs out of memory during a write, before
IOException
is thrown - by calling
close()
- in
finalize()
WARNING could deadlock if device not synced and inside beginExclusive/endExclusive block.
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 accommodate legacy implementations
Usage
Example
Write to a 1-Wire file on device 'owd':
// create a 1-Wire file at root
OWFileOutputStream outstream = new OWFileOutputStream(owd, "DEMO.0");
// write the data (in a byte array data[])
outstream.write(data);
// get 1-Wire File descriptor to flush to device
OWFileDescriptor owfd = owfile.getFD();
// loop until sync is successful
do
{
try
{
owfd.sync();
done = true;
}
catch (SyncFailedException e)
{
// do something
...
done = false;
}
}
while (!done)
// close the stream to release system resources
outstream.close();
- See Also:
-
Constructor Summary
ConstructorsConstructorDescriptionOWFileOutputStream
(OWFile file) Creates a file output stream to write to the file represented by the specifiedFile
object.Creates an output file stream to write to the specified file descriptor, which represents an existing connection to an actual file in the Filesystem.OWFileOutputStream
(OneWireContainer[] owd, String name) Creates an output file stream to write to the file with the specified name.OWFileOutputStream
(OneWireContainer[] owd, String name, boolean append) Creates an output file stream to write to the file with the specifiedname
.OWFileOutputStream
(OneWireContainer owd, String name) Creates an output file stream to write to the file with the specified name.OWFileOutputStream
(OneWireContainer owd, String name, boolean append) Creates an output file stream to write to the file with the specifiedname
. -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Closes this file output stream and releases any system resources associated with this stream.void
finalize()
Cleans up the connection to the file, and ensures that theclose
method of this file output stream is called when there are no more references to this stream.getFD()
Returns the file descriptor associated with this stream.void
write
(byte[] b) Writesb.length
bytes from the specified byte array to this file output stream.void
write
(byte[] b, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to this file output stream.void
write
(int b) Writes the specified byte to this file output stream.Methods inherited from class java.io.OutputStream
flush, nullOutputStream
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Constructor Details
-
OWFileOutputStream
Creates an output file stream to write to the file with the specified name. A newOWFileDescriptor
object is created to represent this file connection.First, if there is a security manager, its
checkWrite
method is called withname
as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a
FileNotFoundException
is thrown.- Parameters:
owd
- OneWireContainer that this Filesystem resides onname
- the system-dependent filename- Throws:
OWFileNotFoundException
- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reasonSecurityException
- if a security manager exists and itscheckWrite
method denies write access to the file.
-
OWFileOutputStream
Creates an output file stream to write to the file with the specified name. A newOWFileDescriptor
object is created to represent this file connection.First, if there is a security manager, its
checkWrite
method is called withname
as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a
FileNotFoundException
is thrown.- Parameters:
owd
- array of OneWireContainers that this Filesystem resides onname
- the system-dependent filename- Throws:
OWFileNotFoundException
- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason
-
OWFileOutputStream
public OWFileOutputStream(OneWireContainer owd, String name, boolean append) throws OWFileNotFoundException Creates an output file stream to write to the file with the specifiedname
. If the second argument istrue
, then bytes will be written to the end of the file rather than the beginning. A newOWFileDescriptor
object is created to represent this file connection.First, if there is a security manager, its
checkWrite
method is called withname
as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a
FileNotFoundException
is thrown.- Parameters:
owd
- OneWireContainer that this Filesystem resides onname
- the system-dependent file nameappend
- iftrue
, then bytes will be written to the end of the file rather than the beginning- Throws:
OWFileNotFoundException
- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.SecurityException
- if a security manager exists and itscheckWrite
method denies write access to the file.
-
OWFileOutputStream
public OWFileOutputStream(OneWireContainer[] owd, String name, boolean append) throws OWFileNotFoundException Creates an output file stream to write to the file with the specifiedname
. If the second argument istrue
, then bytes will be written to the end of the file rather than the beginning. A newOWFileDescriptor
object is created to represent this file connection.First, if there is a security manager, its
checkWrite
method is called withname
as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a
FileNotFoundException
is thrown.- Parameters:
owd
- array of OneWireContainers that this Filesystem resides onname
- the system-dependent file nameappend
- iftrue
, then bytes will be written to the end of the file rather than the beginning- Throws:
OWFileNotFoundException
- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.SecurityException
- if a security manager exists and itscheckWrite
method denies write access to the file.
-
OWFileOutputStream
Creates a file output stream to write to the file represented by the specifiedFile
object. A newOWFileDescriptor
object is created to represent this file connection.First, if there is a security manager, its
checkWrite
method is called with the path represented by thefile
argument as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a
FileNotFoundException
is thrown.- Parameters:
file
- the file to be opened for writing.- Throws:
OWFileNotFoundException
- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reasonSecurityException
- if a security manager exists and itscheckWrite
method denies write access to the file.- See Also:
-
OWFileOutputStream
Creates an output file stream to write to the specified file descriptor, which represents an existing connection to an actual file in the Filesystem.First, if there is a security manager, its
checkWrite
method is called with the file descriptorfdObj
argument as its argument.- Parameters:
fdObj
- the file descriptor to be opened for writing.- Throws:
SecurityException
- if a security manager exists and itscheckWrite
method denies write access to the file descriptor.
-
-
Method Details
-
write
Writes the specified byte to this file output stream. Implements thewrite
method ofOutputStream
.- Specified by:
write
in classOutputStream
- Parameters:
b
- the byte to be written.- Throws:
IOException
- if an I/O error occurs.
-
write
Writesb.length
bytes from the specified byte array to this file output stream.- Overrides:
write
in classOutputStream
- Parameters:
b
- the data.- Throws:
IOException
- if an I/O error occurs.
-
write
Writeslen
bytes from the specified byte array starting at offsetoff
to this file output stream.- Overrides:
write
in classOutputStream
- Parameters:
b
- the data.off
- the start offset in the data.len
- the number of bytes to write.- Throws:
IOException
- if an I/O error occurs.
-
close
Closes this file output stream and releases any system resources associated with this stream. This file output stream may no longer be used for writing bytes.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Overrides:
close
in classOutputStream
- Throws:
IOException
- if an I/O error occurs.
-
getFD
Returns the file descriptor associated with this stream.- Returns:
- the
OWFileDescriptor
object that represents the connection to the file in the Filesystem being used by thisFileOutputStream
object. - Throws:
IOException
- if an I/O error occurs.- See Also:
-
finalize
Cleans up the connection to the file, and ensures that theclose
method of this file output stream is called when there are no more references to this stream.- Overrides:
finalize
in classObject
- Throws:
IOException
- if an I/O error occurs.- See Also:
-