Java compact1, compact2, compact3 java.io Class Reader（JDK8）

Field Detail

• 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 Detail

• 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 Detail

• read

  public int read(CharBuffer target)
           throws IOException

  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.

  Specified by:

  read in interface Readable

  Parameters:

  target - the buffer to read characters into

  Returns:

  The number of characters added to the buffer, 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

  Since:

  1.5

• read

  public int read()
           throws IOException

  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)
           throws IOException

  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 - 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)
                    throws IOException

  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 - 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:

  IOException - If an I/O error occurs

• skip

  public long skip(long n)
            throws IOException

  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 - The number of characters to skip

  Returns:

  The number of characters actually skipped

  Throws:

  IllegalArgumentException - If n is negative.

  IOException - If an I/O error occurs

• ready

  public boolean ready()
                throws IOException

  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)
            throws IOException

  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()
             throws IOException

  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()
                      throws IOException

  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 Closeable

  Specified by:

  close in interface AutoCloseable

  Throws:

  IOException - If an I/O error occurs