Added in API level 1

PushbackReader

open class PushbackReader : FilterReader

A character-stream reader that allows characters to be pushed back into the stream.

Summary

Public constructors

Creates a new pushback reader with a one-character pushback buffer.

PushbackReader(in: Reader!, size: Int)

Creates a new pushback reader with a pushback buffer of the given size.

Public methods
open Unit

Closes the stream and releases any system resources associated with it.

open Unit
mark(readAheadLimit: Int)

Marks the present position in the stream.

open Boolean

Tells whether this stream supports the mark() operation, which it does not.

open Int

Reads a single character.

open Int
read(cbuf: CharArray!, off: Int, len: Int)

Reads characters into a portion of an array.

open Boolean

Tells whether this stream is ready to be read.

open Unit

Resets the stream.

open Long
skip(n: Long)

Skips characters.

open Unit
unread(cbuf: CharArray!)

Pushes back an array of characters by copying it to the front of the pushback buffer.

open Unit
unread(cbuf: CharArray!, off: Int, len: Int)

Pushes back a portion of an array of characters by copying it to the front of the pushback buffer.

open Unit
unread(c: Int)

Pushes back a single character by copying it to the front of the pushback buffer.

Inherited functions
Reader! nullReader()

Returns a new Reader that reads no characters. The returned stream is initially open. The stream is closed by calling the close() method. Subsequent calls to close() have no effect.

While the stream is open, the read(), read(char[]), read(char[], int, int), read(Charbuffer), ready(), skip(long), and transferTo() methods all behave as if end of stream has been reached. After the stream has been closed, these methods all throw IOException.

The markSupported() method returns false. The mark() and reset() methods throw an IOException.

The object used to synchronize operations on the returned Reader is not specified.

Int read(cbuf: CharArray!)

Reads characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Int read(target: CharBuffer!)

Attempts to read characters into the specified character buffer. The buffer is used as a repository of characters as-is: the only changes made are the results of a put operation. No flipping or rewinding of the buffer is performed.

Long transferTo(out: Writer!)

Reads all characters from this reader and writes the characters to the given writer in the order that they are read. On return, this reader will be at end of the stream. This method does not close either reader or writer.

This method may block indefinitely reading from the reader, or writing to the writer. The behavior for the case where the reader and/or writer is asynchronously closed, or the thread interrupted during the transfer, is highly reader and writer specific, and therefore not specified.

If an I/O error occurs reading from the reader or writing to the writer, then it may do so after some characters have been read or written. Consequently the reader may not be at end of the stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.

Inherited properties
Reader! in

The underlying character-input stream.

Any! lock

The object used to synchronize operations on this stream. For efficiency, a character-stream object may use an object other than itself to protect critical sections. A subclass should therefore use the object in this field rather than this or a synchronized method.

Public constructors

PushbackReader

Added in API level 1
PushbackReader(in: Reader!)

Creates a new pushback reader with a one-character pushback buffer.

Parameters
in Reader!: The reader from which characters will be read

PushbackReader

Added in API level 1
PushbackReader(
    in: Reader!,
    size: Int)

Creates a new pushback reader with a pushback buffer of the given size.

Parameters
in Reader!: The reader from which characters will be read
size Int: The size of the pushback buffer
Exceptions
java.lang.IllegalArgumentException if size <= 0

Public methods

close

Added in API level 1
open fun close(): Unit

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), unread(), ready(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.

Exceptions
java.lang.Exception if this resource cannot be closed
java.io.IOException if an I/O error occurs
java.io.IOException If an I/O error occurs

mark

Added in API level 1
open fun mark(readAheadLimit: Int): Unit

Marks the present position in the stream. The mark for class PushbackReader always throws an exception.

Parameters
readAheadLimit Int: Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.
Exceptions
java.io.IOException Always, since mark is not supported

markSupported

Added in API level 1
open fun markSupported(): Boolean

Tells whether this stream supports the mark() operation, which it does not.

Return
Boolean true if and only if this stream supports the mark operation.

read

Added in API level 1
open fun read(): Int

Reads a single character.

Return
Int The character read, or -1 if the end of the stream has been reached
Exceptions
java.io.IOException If an I/O error occurs

read

Added in API level 1
open fun read(
    cbuf: CharArray!,
    off: Int,
    len: Int
): Int

Reads characters into a portion of an array.

Parameters
cbuf CharArray!: Destination buffer
off Int: Offset at which to start writing characters
len Int: Maximum number of characters to read
Return
Int The number of characters read, or -1 if the end of the stream has been reached
Exceptions
java.io.IOException If an I/O error occurs
java.lang.IndexOutOfBoundsException If off is negative, or len is negative, or len is greater than cbuf.length - off

ready

Added in API level 1
open fun ready(): Boolean

Tells whether this stream is ready to be read.

Return
Boolean True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
Exceptions
java.io.IOException If an I/O error occurs

reset

Added in API level 1
open fun reset(): Unit

Resets the stream. The reset method of PushbackReader always throws an exception.

Exceptions
java.io.IOException Always, since reset is not supported

skip

Added in API level 1
open fun skip(n: Long): Long

Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

Parameters
n Long: The number of characters to skip
Return
Long The number of characters actually skipped
Exceptions
java.lang.IllegalArgumentException If n is negative.
java.io.IOException If an I/O error occurs

unread

Added in API level 1
open fun unread(cbuf: CharArray!): Unit

Pushes back an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[0], the character after that will have the value cbuf[1], and so forth.

Parameters
cbuf CharArray!: Character array to push back
Exceptions
java.io.IOException If there is insufficient room in the pushback buffer, or if some other I/O error occurs

unread

Added in API level 1
open fun unread(
    cbuf: CharArray!,
    off: Int,
    len: Int
): Unit

Pushes back a portion of an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[off], the character after that will have the value cbuf[off+1], and so forth.

Parameters
cbuf CharArray!: Character array
off Int: Offset of first character to push back
len Int: Number of characters to push back
Exceptions
java.io.IOException If there is insufficient room in the pushback buffer, or if some other I/O error occurs

unread

Added in API level 1
open fun unread(c: Int): Unit

Pushes back a single character by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value (char)c.

Parameters
c Int: The int value representing a character to be pushed back
Exceptions
java.io.IOException If the pushback buffer is full, or if some other I/O error occurs