ConsoleInputStream (Jython API documentation)
Date: 2020-03-21

org.python.util

## Class ConsoleInputStream

- java.lang.Object
- - java.io.InputStream
  - - java.io.FilterInputStream
    - - org.python.util.ConsoleInputStream

- All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable

      public abstract class ConsoleInputStream
      extends java.io.FilterInputStream

  This class is intended to replace `System.in` for use with console libraries that provide a line-oriented input mechanism. The console libraries provide a method to get the next line from the console as a String. Particular sub-classes should wrap this character-oriented method in a definition of `getLine()`.

  The libraries JLine and Java Readline have both been used to give Jython line-recall, editing and a line history preserved between sessions. Both deal with the console encoding internally, and interact with the user in terms of a buffer of characters. Our need in Jython is to access a byte-stream encoding the characters, with line-endings, since it is the text layer of the Python io stack, whether we are using the `io` module or `file` built-in, that should deal with encoding.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `ConsoleInputStream.EOLPolicy` Enumeration used to specify whether an end-of-line should be added or replaced at the end of each line read.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `available()` The number of bytes left unread in the current encoded line.
    `void` | `mark(int readlimit)` Mark is not supported.
    `boolean` | `markSupported()` Mark is not supported.
    `int` | `read()` Read the next byte of data from the buffered input line.
    `int` | `read(byte[] b, int off, int len)` Reads up to len bytes of data from this input stream into an array of bytes.
    `void` | `reset()` Mark is not supported.
    `long` | `skip(long n)` Skip forward n bytes within the current encoded line.

    - ### Methods inherited from class java.io.FilterInputStream

      `close, read`

    - ### Methods inherited from class java.lang.Object

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

- - ### Method Detail

    - #### read

          public int read()
                   throws java.io.IOException

      Read the next byte of data from the buffered input line. The byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been recognised, the value -1 is returned. This method blocks until input data are available, the end of the stream is detected, or an exception is thrown. Normally, an empty line results in an encoded end-of-line being returned.
      Overrides:
        `read` in class `java.io.FilterInputStream`
      Throws:
        `java.io.IOException`

    - #### read

          public int read(byte[] b,
                          int off,
                          int len)
                   throws java.io.IOException,
                          java.io.EOFException

      Reads up to len bytes of data from this input stream into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned. This implementation calls `getLine()` at most once to get a line of characters from the console, and encodes them as bytes to be read back from the stream.
      Overrides:
        `read` in class `java.io.FilterInputStream`
      Throws:
        `java.io.IOException`
        `java.io.EOFException`

    - #### skip

          public long skip(long n)
                    throws java.io.IOException

      Skip forward n bytes within the current encoded line. A call to `skip` will not result in reading a new line with `getLine()`.
      Overrides:
        `skip` in class `java.io.FilterInputStream`
      Throws:
        `java.io.IOException`

    - #### available

          public int available()
                        throws java.io.IOException

      The number of bytes left unread in the current encoded line.
      Overrides:
        `available` in class `java.io.FilterInputStream`
      Throws:
        `java.io.IOException`

    - #### mark

          public void mark(int readlimit)

      Mark is not supported.
      Overrides:
        `mark` in class `java.io.FilterInputStream`

    - #### reset

          public void reset()
                     throws java.io.IOException

      Mark is not supported.
      Overrides:
        `reset` in class `java.io.FilterInputStream`
      Throws:
        `java.io.IOException`

    - #### markSupported

          public boolean markSupported()

      Mark is not supported.
      Overrides:
        `markSupported` in class `java.io.FilterInputStream`

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