Field Summary

Constructor Summary

Method Summary

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 thanthis or a synchronized method.

Constructor Details

• Reader

  protected Reader()

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

• Reader

  protected Reader(Object lock)

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

  Parameters:

  lock - The Object to synchronize on.

Method Details

• nullReader

  public static Reader nullReader()

  Returns a newReader that reads no characters. The returned stream is initially open. The stream is closed by calling theclose() method. Subsequent calls toclose() have no effect.

  While the stream is open, theread(),read(char[]),read(char[], int, int),read(CharBuffer), ready(),skip(long), andtransferTo() methods all behave as if end of stream has been reached. After the stream has been closed, these methods all throwIOException.

  ThemarkSupported() method returnsfalse. Themark() andreset() methods throw anIOException.

  Theobject used to synchronize operations on the returnedReader is not specified.

  Returns:

  aReader which reads no characters

  Since:

  11

• of

  public static Reader of(CharSequence cs)

  Returns aReader that reads characters from aCharSequence. The reader is initially open and reading starts at the first character in the sequence.

  The returned reader supports themark() andreset() operations.

  The resulting reader is not safe for use by multiple concurrent threads. If the reader is to be used by more than one thread it should be controlled by appropriate synchronization.

  If the sequence changes while the reader is open, e.g. the length changes, the behavior is undefined.

  Parameters:

  cs -CharSequence providing the character stream.

  Returns:

  aReader which reads characters fromcs

  Throws:

  NullPointerException - ifcs isnull

  Since:

  24

• read

  public int read(CharBuffer target) throwsIOException

  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. If thelength of the specified character buffer is zero, then no characters will be read and zero will be returned.

  Specified by:

  read in interface Readable

  Parameters:

  target - the buffer to read characters into

  Returns:

  The number of characters added to the buffer, possibly zero, or -1 if this source of characters is at its end

  Throws:

  IOException - if an I/O error occurs

  NullPointerException - if target is null

  ReadOnlyBufferException - if target is a read only buffer, even if its length is zero

  Since:

  1.5

• read

  public int read() throwsIOException

  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.

  Returns:

  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

  Throws:

  IOException - If an I/O error occurs

• read

  public int read(char[] cbuf) throwsIOException

  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.

  If the length ofcbuf is zero, then no characters are read and0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value-1 is returned; otherwise, at least one character is read and stored intocbuf.

  Parameters:

  cbuf - Destination buffer

  Returns:

  The number of characters read, or -1 if the end of the stream has been reached

  Throws:

  IOException - If an I/O error occurs

• read

  public abstract int read(char[] cbuf, int off, int len) throwsIOException

  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.

  Iflen is zero, then no characters are read and0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value-1 is returned; otherwise, at least one character is read and stored intocbuf.

  Parameters:

  cbuf - Destination buffer

  off - Offset at which to start storing characters

  len - Maximum number of characters to read

  Returns:

  The number of characters read, or -1 if the end of the stream has been reached

  Throws:

  IndexOutOfBoundsException - Ifoff is negative, orlen is negative, orlen is greater thancbuf.length - off

  IOException - If an I/O error occurs

• skip

  public long skip(long n) throwsIOException

  Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.

  Parameters:

  n - The number of characters to skip

  Returns:

  The number of characters actually skipped

  Throws:

  IllegalArgumentException - Ifn is negative.

  IOException - If an I/O error occurs

• ready

  public boolean ready() throwsIOException

  Tells whether this stream is ready to be read.

  Returns:

  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.

  Throws:

  IOException - If an I/O error occurs

• markSupported

  public boolean markSupported()

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

  Returns:

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

• mark

  public void mark(int readAheadLimit) throwsIOException

  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 - 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.

  Throws:

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

• reset

  public void reset() throwsIOException

  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().

  Throws:

  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

• close

  public abstract void close() throwsIOException

  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.

  Specified by:

  close in interface AutoCloseable

  Specified by:

  close in interface Closeable

  Throws:

  IOException - If an I/O error occurs

• transferTo

  public long transferTo(Writer out) throwsIOException

  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 isasynchronously closed, or the thread interrupted during the transfer, is highly reader and writer specific, and therefore not specified.

  If the total number of characters transferred is greater thanLong.MAX_VALUE, thenLong.MAX_VALUE will be returned.

  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.

  Parameters:

  out - the writer, non-null

  Returns:

  the number of characters transferred

  Throws:

  IOException - if an I/O error occurs when reading or writing

  NullPointerException - ifout isnull

  Since:

  10