org.python.core.io

Class IOBase

java.lang.Object

org.python.core.io.IOBase

Direct Known Subclasses:

BufferedIOBase, RawIOBase, TextIOBase

public abstract class IOBase
extends java.lang.Object

Base class for all I/O classes. IOBase and its descendents in org.python.core.io are based off Python 3's new io module (PEP 3116). This does not define read(), readinto() and write(), nor readline() and friends, since their signatures vary per layer.

Author:

Philip Jenvey

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_BUFFER_SIZE The default size of generic buffers

Constructor Summary

Constructors

Constructor and Description
IOBase()

Method Summary

Methods

Modifier and Type	Method and Description
java.io.InputStream	asInputStream() Coerce this into an InputStream if possible, or return null.
java.io.OutputStream	asOutputStream() Coerce this into an OutputStream if possible, or return null.
void	checkClosed() Raise a ValueError if the file is closed.
void	checkReadable() Raise an IOError if the file is not readable.
void	checkWritable() Raise an IOError if the file is not writable.
void	close() Flushes and closes the IO object.
boolean	closed() Return whether this file has been closed.
RawIOBase	fileno() Returns underlying file descriptor if one exists.
void	flush() Flushes write buffers, if applicable.
boolean	isatty() Returns whether this is an 'interactive' stream.
boolean	readable() Return whether this file was opened for reading.
long	seek(long pos) Seek to byte offset pos relative to the start of the stream.
long	seek(long pos, int whence) Seek to byte offset pos relative to position indicated by whence: 0 Start of stream (the default). pos should be >= 0; 1 Current position - whence may be negative; 2 End of stream - whence usually negative.
long	tell() Return the current stream position.
long	truncate(long size) Truncate file to size in bytes.
boolean	writable() Return whether this file was opened for writing.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

The default size of generic buffers

See Also:

Constant Field Values

Constructor Detail

IOBase

public IOBase()

Method Detail

seek

public long seek(long pos)

Seek to byte offset pos relative to the start of the stream. Returns the new absolute position.

Parameters:

pos - a long position value

Returns:

a long position value seeked to

seek

public long seek(long pos,
        int whence)

Seek to byte offset pos relative to position indicated by whence: 0 Start of stream (the default). pos should be >= 0; 1 Current position - whence may be negative; 2 End of stream - whence usually negative. Returns the new absolute position.

Parameters:

pos - a long position value

whence - an int whence value

Returns:

a long position value seeked to

tell

public long tell()

Return the current stream position.

Returns:

a long position value

truncate

public long truncate(long size)

Truncate file to size in bytes. Returns the new size.

Parameters:

size - a long size to truncate to

Returns:

a long size value the file was truncated to

flush

public void flush()

Flushes write buffers, if applicable. This is a no-op for read-only and non-blocking streams.

close

public void close()

Flushes and closes the IO object. This must be idempotent. It should also set a flag for the 'closed' property (see below) to test.

fileno

public RawIOBase fileno()

Returns underlying file descriptor if one exists. Raises IOError if the IO object does not use a file descriptor.

Returns:

a file descriptor

isatty

public boolean isatty()

Returns whether this is an 'interactive' stream. Returns False if we don't know.

Returns:

a boolean, true if an 'interactive' stream

readable

public boolean readable()

Return whether this file was opened for reading.

Returns:

true if the file was opened for reading

checkReadable

public void checkReadable()

Raise an IOError if the file is not readable.

writable

public boolean writable()

Return whether this file was opened for writing.

Returns:

true if the file was opened for writing

checkWritable

public void checkWritable()

Raise an IOError if the file is not writable.

closed

public boolean closed()

Return whether this file has been closed.

Returns:

true if the file has been closed

checkClosed

public void checkClosed()

Raise a ValueError if the file is closed.

asOutputStream

public java.io.OutputStream asOutputStream()

Coerce this into an OutputStream if possible, or return null.

asInputStream

public java.io.InputStream asInputStream()

Coerce this into an InputStream if possible, or return null.