| java.lang.Object
 java.io.Reader
| Reader | | abstract public class Reader (Code) | | 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.
version:
12/17/01 (CLDC 1.1)
See Also: java.io.InputStreamReader
See Also: java.io.Writer
since:
JDK1.1, CLDC 1.0 |
| Field Summary | |
| protected Object | lock
The object used to synchronize operations on this stream. |
| Constructor Summary | |
| 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. |
| Method Summary | |
| abstract public void | close()
Close the stream. | | public void | mark(int readAheadLimit)
Mark the present position in the stream. | | public boolean | markSupported()
Tell whether this stream supports the mark() operation. | | public int | read()
Read a single character. | | public int | read(char cbuf)
Read characters into an array. | | abstract public int | read(char cbuf, int off, int len)
Read characters into a portion of an array. | | public boolean | ready()
Tell whether this stream is ready to be read.
True if the next read() is guaranteed not to block for input,false otherwise. | | public void | reset()
Reset the stream. | | public long | skip(long n)
Skip characters. |
| lock | | protected Object lock(Code) | | 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.
|
| Reader | | protected Reader()(Code) | | Create a new character-stream reader whose critical sections will
synchronize on the reader itself.
|
| Reader | | protected Reader(Object lock)(Code) | | Create a new character-stream reader whose critical sections will
synchronize on the given object.
Parameters:
lock - The Object to synchronize on. |
| close | | abstract public void close() throws IOException(Code) | | 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.
exception:
IOException - If an I/O error occurs |
| mark | | public void mark(int readAheadLimit) throws IOException(Code) | | 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.
Parameters:
readAheadLimit - Limit on the number of characters that may beread while still preserving the mark. Afterreading this many characters, attempting toreset the stream may fail.
exception:
IOException - If the stream does not support mark(),or if some other I/O error occurs |
| markSupported | | public boolean markSupported()(Code) | | Tell whether this stream supports the mark() operation. The default
implementation always returns false. Subclasses should override this
method.
true if and only if this stream supports the mark operation. |
| read | | public int read() throws IOException(Code) | | 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.
The character read, as an integer in the range 0 to 65535(0x00-0xffff), or -1 if the end of the stream hasbeen reached
exception:
IOException - If an I/O error occurs |
| read | | public int read(char cbuf) throws IOException(Code) | | 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.
Parameters:
cbuf - Destination buffer The number of bytes read, or -1 if the end of the streamhas been reached
exception:
IOException - If an I/O error occurs |
| read | | abstract public int read(char cbuf, int off, int len) throws IOException(Code) | | 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.
Parameters:
cbuf - Destination buffer
Parameters:
off - Offset at which to start storing characters
Parameters:
len - Maximum number of characters to read The number of characters read, or -1 if the end of thestream has been reached
exception:
IOException - If an I/O error occurs |
| ready | | public boolean ready() throws IOException(Code) | | Tell whether this stream is ready to be read.
True if the next read() is guaranteed not to block for input,false otherwise. Note that returning false does not guarantee that thenext read will block.
exception:
IOException - If an I/O error occurs |
| reset | | public void reset() throws IOException(Code) | | 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().
exception:
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 | | public long skip(long n) throws IOException(Code) | | Skip 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 The number of characters actually skipped
exception:
IllegalArgumentException - If n is negative.
exception:
IOException - If an I/O error occurs |
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