java.io
public abstract class Reader extends Object implements Closeable, Readable
UNKNOWN: April 21, 1998.
| Field Summary | |
|---|---|
| protected Object | lock 
 This is the  Objectused for synchronizing critical code
 sections. | 
| Constructor Summary | |
|---|---|
| protected | Reader() 
 Unitializes a  Readerthat will use the object
 itself for synchronization of critical code sections. | 
| protected | Reader(Object lock) 
 Initializes a  Readerthat will use the specifiedObjectfor synchronization of critical code sections. | 
| Method Summary | |
|---|---|
| abstract void | close() 
 Closes the stream.   | 
| void | mark(int readLimit) 
 Marks a position in the input to which the stream can be
 "reset" by calling the  reset()method. | 
| boolean | markSupported() 
 Returns a boolean that indicates whether the mark/reset
 methods are supported in this class.   | 
| abstract int | read(char[] buf, int offset, int count) 
 Read chars from a stream and stores them into a caller
 supplied buffer.   | 
| int | read(char[] buf) 
 Reads chars from a stream and stores them into a caller
 supplied buffer.   | 
| int | read() 
 Reads an char from the input stream and returns it
 as an int in the range of 0-65535.   | 
| int | read(CharBuffer buffer) | 
| boolean | ready() 
 Determines whether or not this stream is ready to be
 read.   | 
| void | reset() 
 Resets a stream to the point where the  mark()method was called. | 
| long | skip(long count) 
 Skips the specified number of chars in the stream.   | 
Object used for synchronizing critical code
 sections.  Subclasses should use this variable instead of a 
 synchronized method or an explicit synchronization on thisReader that will use the object
 itself for synchronization of critical code sections.Reader that will use the specified
 Object for synchronization of critical code sections.
Parameters: lock The Object to use for synchronization 
IOException.
Throws: IOException If an error occurs
reset() method.  The parameter
 readlimit is the number of chars that can be read from the 
 stream after setting the mark before the mark becomes invalid.  For
 example, if mark() is called with a read limit of 10, then 
 when 11 chars of data are read from the stream before the 
 reset() method is called, then the mark is invalid and the 
 stream object instance is not required to remember the mark.
Parameters: readLimit The number of chars that can be read before the mark becomes invalid
Throws: IOException If an error occurs such as mark not being supported for this class
 This method always returns false in this class, but
 subclasses can override this method to return true if they 
 support mark/reset functionality.
Returns: true if mark/reset functionality is supported, 
         false otherwise
 
offset 
 into the buffer and attempts to read len chars.  This method 
 can return before reading the number of chars requested.  The actual 
 number of chars read is returned as an int.  A -1 is returned to indicate 
 the end of the stream.
 This method will block until some data can be read.
 This method operates by calling the single char read() method
 in a loop until the desired number of chars are read.  The read loop
 stops short if the end of the stream is encountered or if an IOException
 is encountered on any read operation except the first.  If the first
 attempt to read a chars fails, the IOException is allowed to propagate
 upward.  And subsequent IOException is caught and treated identically
 to an end of stream condition.  Subclasses can (and should if possible)
 override this method to provide a more efficient implementation.
Parameters: buf The array into which the chars read should be stored offset The offset into the array to start storing chars count The requested number of chars to read
Returns: The actual number of chars read, or -1 if end of stream.
Throws: IOException If an error occurs.
This method will block until some data can be read.
 This method operates by calling an overloaded read method like so:
 read(buf, 0, buf.length)
Parameters: buf The buffer into which the chars read will be stored.
Returns: The number of chars read or -1 if end of stream.
Throws: IOException If an error occurs.
This method will block until the char can be read.
Returns: The char read or -1 if end of stream
Throws: IOException If an error occurs
Since: 1.5
false the stream may block if a
 read is attempted, but it is not guaranteed to do so.
 
 This method always returns false in this class
Returns: true if the stream is ready to be read, 
 false otherwise.
 
Throws: IOException If an error occurs
mark() 
 method was called.  Any chars that were read after the mark point was 
 set will be re-read during subsequent reads.
 This method always throws an IOException in this class, but subclasses can override this method if they provide mark/reset functionality.
Throws: IOException Always thrown for this class
This method reads and discards chars into a 256 char array until the specified number of chars were skipped or until either the end of stream is reached or a read attempt returns a short count. Subclasses can override this method to provide a more efficient implementation where one exists.
Parameters: count The requested number of chars to skip
Returns: The actual number of chars skipped.
Throws: IOException If an error occurs