IOBase (Jython API documentation)

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

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()

Constructors
Constructor and Description
`IOBase()`

Method Summary

All Methods Instance Methods Concrete 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`.
`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.
    Semantics
    whence Seek to pos
    
    0 Start of stream (the default). Should be ≥0.
    
    1 Current position + pos Either sign.
    
    2 End of stream + pos Usually ≤0.
    
    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.

`whence`	Seek to	`pos`
0	Start of stream (the default).	Should be ≥0.
1	Current position + `pos`	Either sign.
2	End of stream + `pos`	Usually ≤0.

Class IOBase

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_BUFFER_SIZE

Constructor Detail

IOBase

Method Detail

seek

seek

tell

truncate

flush

close

fileno

isatty

readable

checkReadable

writable

checkWritable

closed

checkClosed

asOutputStream

asInputStream