Class 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 Description
      static int DEFAULT_BUFFER_SIZE
      The default size of generic buffers
    • Constructor Summary

      Constructors 
      Constructor Description
      IOBase()  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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.