Added in API level 1

Reader

abstract class Reader : Readable, Closeable

kotlin.Any
↳	java.io.Reader

Known Direct Subclasses

BufferedReader, CharArrayReader, FilterReader, InputStreamReader, PipedReader, StringReader

BufferedReader	Reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.
CharArrayReader	This class implements a character buffer that can be used as a character-input stream.
FilterReader	Abstract class for reading filtered character streams.
InputStreamReader	An InputStreamReader is a bridge from byte streams to character streams: It reads bytes and decodes them into characters using a specified .
PipedReader	Piped character-input streams.
StringReader	A character stream whose source is a string.

Known Indirect Subclasses

FileReader, LineNumberReader, PushbackReader

FileReader	Convenience class for reading character files.
LineNumberReader	A buffered character-input stream that keeps track of line numbers.
PushbackReader	A character-stream reader that allows characters to be pushed back into the stream.

Abstract class for reading character streams. The only methods that a subclass must implement are read(char[], int, int) and close(). Most subclasses, however, will override some of the methods defined here in order to provide higher efficiency, additional functionality, or both.

Summary

Protected constructors
`<init>()` Creates a new character-stream reader whose critical sections will synchronize on the reader itself.
`<init>(lock: Any!)` Creates a new character-stream reader whose critical sections will synchronize on the given object.

Public methods
abstract Unit	`close()` 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	`markSupported()` Tells whether this stream supports the mark() operation.
open Int	`read(target: CharBuffer!)` Attempts to read characters into the specified character buffer.
open Int	`read()` Reads a single character.
open Int	`read(cbuf: CharArray!)` Reads characters into an array.
abstract Int	`read(cbuf: CharArray!, off: Int, len: Int)` Reads characters into a portion of an array.
open Boolean	`ready()` Tells whether this stream is ready to be read.
open Unit	`reset()` Resets the stream.
open Long	`skip(n: Long)` Skips characters.

Properties
Any!	`lock` The object used to synchronize operations on this stream.

Protected constructors

<init>

Added in API level 1

protected Reader()

Creates a new character-stream reader whose critical sections will synchronize on the reader itself.

<init>

Added in API level 1

protected Reader(lock: Any!)

Creates a new character-stream reader whose critical sections will synchronize on the given object.

Parameters
`lock`	Any!: The Object to synchronize on.

Public methods

close

Added in API level 1

abstract fun close(): Unit

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

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. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.

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`	If the stream does not support mark(), or if some other I/O error occurs

markSupported

Added in API level 1

open fun markSupported(): Boolean

Tells whether this stream supports the mark() operation. The default implementation always returns false. Subclasses should override this method.

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

read

Added in API level 1

open fun read(target: CharBuffer!): Int

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.

Parameters
`cb`	the buffer to read characters into
`target`	CharBuffer!: the buffer to read characters into

Return
`Int`	The number of characters added to the buffer, or -1 if this source of characters is at its end

Exceptions
`java.io.IOException`	if an I/O error occurs
`java.lang.NullPointerException`	if target is null
`java.nio.ReadOnlyBufferException`	if target is a read only buffer

read

Added in API level 1

open fun read(): Int

Reads a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.

Subclasses that intend to support efficient single-character input should override this method.

Return
`Int`	The character read, as an integer in the range 0 to 65535 (0x00-0xffff), 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!): Int

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.

Parameters
`cbuf`	CharArray!: Destination buffer

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

read

Added in API level 1

abstract fun read(
    cbuf: CharArray!, 
    off: Int, 
    len: Int
): Int

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

Parameters
`cbuf`	CharArray!: Destination buffer
`off`	Int: Offset at which to start storing 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

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. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().

Exceptions
`java.io.IOException`	If the stream has not been marked, or if the mark has been invalidated, or if the stream does not support reset(), or if some other I/O error occurs

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

Properties

lock

Added in API level 1

protected var lock: Any!

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.