Package org.python.modules._io

Class PyIOBase

java.lang.Object
org.python.core.PyObject
org.python.modules._io.PyIOBase
All Implemented Interfaces:
Serializable, FinalizableBuiltin, Traverseproc
Direct Known Subclasses:
PyIOBaseDerived, PyRawIOBase
public class PyIOBase extends PyObject implements FinalizableBuiltin, Traverseproc
The Python module _io._IOBase, on which the io module depends directly.

Implementation note: The code is based heavily on the Jython 2.6-ish _fileio.PyFileIO, the purely Java-accessible IOBase (both Philip Jenvey's work), and the Python implementation in Lib/_pyio. We do not simply delegate to the implementation in org.python.core.io because of the need to override parts of the implementation in Python subclasses. A call to close(), for example, is required to call flush(), but if delegated to the pure Java implementation would not call the version of flush() overridden in a Python sub-class of _io._IOBase. Equally, the use made by PyRawIOBase.read(int) of readinto(bytearray) would not pick up the version of readinto defined in Python.

See Also:

  • Field Details

  • Method Details

    • fastGetDict

      public PyStringMap fastGetDict()
      Description copied from class: PyObject
      xxx implements where meaningful
      Overrides:
      fastGetDict in class PyObject
      Returns:
      internal object per instance dict or null

    • seek

      public long seek(long pos, int whence)
      Position the read or write pointer at a given byte offset pos relative to a position indicated by whence.
      • If whence=0, the position will be set to pos bytes.
      • If whence=1 the position will be set to the current position plus pos.
      • If whence=2 the position will be set to the stream size plus pos (and usually pos<=0).
      Parameters:
      pos - relative to the specified point
      whence - 0=from start, 1=from here, 2=from end
      Returns:
      the new current position

    • seek

      public final long seek(long pos)
      Position the read or write pointer at a given byte offset pos relative to the start.
      Parameters:
      pos - relative to the start
      Returns:
      the new current position

    • tell

      public long tell()
      Get the current stream position.
      Returns:
      stream position

    • truncate

      public long truncate(long size)
      Truncate file to size bytes.
      Parameters:
      size - requested for stream
      Returns:
      the new size

    • truncate

      public long truncate()
      Truncate file to size bytes to the current position (as reported by tell()).
      Returns:
      the new size

    • flush

      public void flush()
      Flush write buffers, or no-op for read-only and non-blocking streams. Irrespective of the concrete type of the i/o object, locally-buffered write data is written downstream. Whether the downstream in object is also flushed depends upon the specific type of this object.

    • closed_readonly

      public final void closed_readonly(boolean value)

    • close

      public void close()
      Close the stream. If closed already, this is a no-op.

    • seekable

      public boolean seekable() throws PyException
      Is the stream capable of positioning the read/write pointer?
      Returns:
      True if may be positioned
      Throws:
      PyException - ValueError if the object is closed to client operations

    • _checkSeekable

      public void _checkSeekable(String msg)
      Raise an error if the pointer of underlying IO stream is not capable of being positioned.
      Parameters:
      msg - optional custom message
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not capable of being positioned.

    • _checkSeekable

      public final void _checkSeekable()
      Raise an error if the pointer of underlying IO stream is not capable of being positioned.
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not capable of being positioned.

    • readable

      public boolean readable() throws PyException
      Is the stream readable?
      Returns:
      true if readable
      Throws:
      PyException - ValueError if the object is closed to client operations

    • _checkReadable

      public void _checkReadable(String msg)
      Raise an error if the underlying IO stream is not readable.
      Parameters:
      msg - optional custom message
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not readable.

    • _checkReadable

      public final void _checkReadable()
      Raise an error if the underlying IO stream is not readable.
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not readable.

    • writable

      public boolean writable() throws PyException
      Is the stream writable?
      Returns:
      true if writable
      Throws:
      PyException - ValueError if the object is closed to client operations

    • _checkWritable

      public void _checkWritable(String msg) throws PyException
      Raise an error if the underlying IO stream is not writable.
      Parameters:
      msg - optional custom message
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not writable.

    • _checkWritable

      public final void _checkWritable() throws PyException
      Raise an error if the underlying IO stream is not writable.
      Throws:
      PyException - ValueError if the object is closed to client operations
      PyException - IOError if the stream is not writable.

    • closed

      public final boolean closed()
      Is the stream closed against further client operations?
      Returns:
      true if closed

    • _checkClosed

      public void _checkClosed(String msg) throws PyException
      Raise an error if the underlying IO stream is closed. (Note opposite sense from _checkSeekable(java.lang.String), etc..
      Parameters:
      msg - optional custom message
      Throws:
      PyException - ValueError if the object is closed to client operations

    • _checkClosed

      public final void _checkClosed() throws PyException
      Throws:
      PyException

    • __enter__

      public PyObject __enter__()
      Called at the start of a context-managed suite (supporting the with clause).
      Returns:
      this object

    • __exit__

      public boolean __exit__(PyObject type, PyObject value, PyObject traceback)
      Called at the end of a context-managed suite (supporting the with clause), and will normally close the stream.
      Returns:
      false

    • fileno

      public PyObject fileno()
      Return a file descriptor for the stream. A CPython file descriptor is an int, but this is not the natural choice in Jython, since Java has no such convention of using integers. File descriptors should be passed around opaquely, so their actual type is irrelevant, as long as (say) _jyio.open(PyObject[], String[]) accepts the type that RawIOBase.fileno() returns.
      Returns:
      a file descriptor (as opaque object)

    • isatty

      public boolean isatty()
      Is the stream known to be an interactive console? This relies on the ability of the underlying stream to know, which is not always possible.
      Returns:
      true if a console: false if not or we can't tell

    • readline

      public PyObject readline(int limit)
      Return one line of text (bytes terminates by '\n'), or the specified number of bytes, or the whole stream, whichever is shortest.
      Parameters:
      limit - maximum number of bytes (<0 means no limit)
      Returns:
      the line (or fragment)

    • readline

      public PyObject readline()
      Return one line of text (bytes terminates by '\n'), or the whole stream, whichever is shorter.
      Returns:
      the line (or fragment)

    • __iter__

      public PyObject __iter__()
      Return an iterator on which next may be repeatedly called to produce (usually) lines from this stream or file.
      Overrides:
      __iter__ in class PyObject

    • __iternext__

      public PyObject __iternext__()
      Description copied from class: PyObject
      Return the next element of the sequence that this is an iterator for. Returns null when the end of the sequence is reached.
      Overrides:
      __iternext__ in class PyObject

    • next

      public PyObject next() throws PyException
      May be called repeatedly to produce (usually) lines from this stream or file.
      Returns:
      next line from the stream or file
      Throws:
      PyException - StopIteration when iteration has reached a natural conclusion
      PyException - ValueError if the file or stream is closed
      PyException - IOError reflecting an I/O error in during the read

    • readlines

      public PyObject readlines(PyObject hint)
      Read a stream as a sequence of lines.
      Parameters:
      hint - stop reading lines after this many bytes (if not EOF first)
      Returns:
      list containing the lines read

    • writelines

      public void writelines(PyObject lines)
      Write an iterable sequence of strings to the stream.
      Parameters:
      lines -

    • __del_builtin__

      public void __del_builtin__()
      Description copied from interface: FinalizableBuiltin
      FinalizableBuiltin.__del_builtin__() is the built-in's own finalizer, while FinalizablePyObjectDerived.__del_derived__() refers to an instance's in-dict __del__. A FinalizeTrigger calls FinalizablePyObjectDerived.__del_derived__() first and - if existent - FinalizableBuiltin.__del_builtin__() after that. A plain FinalizablePyObject.__del__() would behave as overridden by FinalizablePyObjectDerived.__del_derived__(), i.e. won't be called if the type implements FinalizablePyObjectDerived, while FinalizableBuiltin.__del_builtin__() is called in any case.
      Specified by:
      __del_builtin__ in interface FinalizableBuiltin

    • traverse

      public int traverse(Visitproc visit, Object arg)
      Description copied from interface: Traverseproc
      Traverses all directly contained PyObjects. Like in CPython, arg must be passed unmodified to visit as its second parameter. If Visitproc.visit(PyObject, Object) returns nonzero, this return value must be returned immediately by traverse. Visitproc.visit(PyObject, Object) must not be called with a null PyObject-argument.
      Specified by:
      traverse in interface Traverseproc

    • refersDirectlyTo

      public boolean refersDirectlyTo(PyObject ob)
      Description copied from interface: Traverseproc
      Optional operation. Should only be implemented if it is more efficient than calling Traverseproc.traverse(Visitproc, Object) with a visitproc that just watches out for ob. Must return false if ob is null.
      Specified by:
      refersDirectlyTo in interface Traverseproc