public abstract class Reader

  1. Object
  2. Reader

ImplementsAutoCloseable

Known subtypesCharArrayReader, StringReader, InputStreamReader, StringReader

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. Since: JDK1.1, CLDC 1.0 See Also:InputStreamReader, Writer

Fields

protected Object lockThe object used to synchronize operations on this stream.

Constructors

protected Reader()Create a new character-stream reader whose critical sections will synchronize on the reader itself.
protected Reader(Object lock)Create a new character-stream reader whose critical sections will synchronize on the given object.

Methods

public abstract void close() throws IOExceptionClose the stream.
public void mark(int readAheadLimit) throws IOExceptionMark the present position in the stream.
public boolean markSupported()Tell whether this stream supports the mark() operation.
public int read() throws IOExceptionRead a single character.
public int read(char[] cbuf) throws IOExceptionRead characters into an array.
public abstract int read(char[] cbuf, int off, int len) throws IOExceptionRead characters into a portion of an array.
public boolean ready() throws IOExceptionTell whether this stream is ready to be read.
public void reset() throws IOExceptionReset the stream.
public long skip(long n) throws IOExceptionSkip characters.

Inherited methods

From Object

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

Field details

lock

protected Object 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.

Constructor details

Reader

protected Reader()
Create a new character-stream reader whose critical sections will synchronize on the reader itself.

Reader

protected Reader(Object lock)
Create a new character-stream reader whose critical sections will synchronize on the given object. lock - The Object to synchronize on.

Method details

close

public abstract void close() throws IOException
Close the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

Throws

IOException

mark

public void mark(int readAheadLimit) throws IOException
Mark 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.

Throws

IOException

markSupported

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

read

public int read() throws IOException
Read 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.

Throws

IOException

read

public int read(char[] cbuf) throws IOException
Read 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.

Throws

IOException

read

public abstract int read(char[] cbuf, int off, int len) throws IOException
Read 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.

Throws

IOException

ready

public boolean ready() throws IOException
Tell whether this stream is ready to be read.

Throws

IOException

reset

public void reset() throws IOException
Reset 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().

Throws

IOException

skip

public long skip(long n) throws IOException
Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

Throws

IOException