public class BufferedReaderBytesRead extends ReaderNeed to keep track of actual bytes read and take advantage of buffered reader performance. Took java source for BufferedReader and added BytesRead functionality
---------- original buffered reader ----------------------
Reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.
The buffer size may be specified, or the default size may be used. The default is large enough for most purposes.
In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReaderBytesRead around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders. For example,
BufferedReaderBytesRead in = new BufferedReaderBytesRead(new FileReader("foo.in"));will buffer the input from the specified file. Without buffering, each invocation of read() or readLine() could cause bytes to be read from the file, converted into characters, and then returned, which can be very inefficient.
Programs that use DataInputStreams for textual input can be localized by replacing each DataInputStream with an appropriate BufferedReaderBytesRead.
Constructors Constructor Description
BufferedReaderBytesRead(Reader in)Creates a buffering character-input stream that uses a default-sized input buffer.
BufferedReaderBytesRead(Reader in, int sz)Creates a buffering character-input stream that uses an input buffer of the specified size.
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
getBytesRead()Keep track of bytesread via ReadLine to account for CR-LF in the stream.
mark(int readAheadLimit)Marks the present position in the stream.
markSupported()Tells whether this stream supports the mark() operation, which it does.
read()Reads a single character.
read(char cbuf, int off, int len)Reads characters into a portion of an array.
readLine()Reads a line of text.
ready()Tells whether this stream is ready to be read.
reset()Resets the stream to the most recent mark.
skip(long n)Skips characters.
public BufferedReaderBytesRead(Reader in, int sz)Creates a buffering character-input stream that uses an input buffer of the specified size.
in- A Reader
sz- Input-buffer size
IllegalArgumentException- If sz is <= 0
public long getBytesRead()Keep track of bytesread via ReadLine to account for CR-LF in the stream. Does not keep track of position if use methods other than ReadLine. //TODO should override other methods and throw exception or keep track of bytes read
public int read() throws IOExceptionReads a single character.
public int read(char cbuf, int off, int len) throws IOExceptionReads characters into a portion of an array.
This method implements the general contract of the corresponding
method of the
class. As an additional convenience, it attempts to read as many characters as possible by repeatedly invoking the
readmethod of the underlying stream. This iterated
readcontinues until one of the following conditions becomes true:
- The specified number of characters have been read,
readmethod of the underlying stream returns
-1, indicating end-of-file, or
readymethod of the underlying stream returns
false, indicating that further input requests would block.
readon the underlying stream returns
-1to indicate end-of-file then this method returns
-1. Otherwise this method returns the number of characters actually read.
Subclasses of this class are encouraged, but not required, to attempt to read as many characters as possible in the same fashion.
Ordinarily this method takes characters from this stream's character buffer, filling it from the underlying stream as necessary. If, however, the buffer is empty, the mark is not valid, and the requested length is at least as large as the buffer, then this method will read characters directly from the underlying stream into the given array. Thus redundant
BufferedReaderBytesReads will not copy data unnecessarily.
public String readLine() throws IOExceptionReads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.
- A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached
IOException- If an I/O error occurs
public long skip(long n) throws IOExceptionSkips characters.
public boolean ready() throws IOExceptionTells whether this stream is ready to be read. A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.
public boolean markSupported()Tells whether this stream supports the mark() operation, which it does.
public void mark(int readAheadLimit) throws IOExceptionMarks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.
readAheadLimit- Limit on the number of characters that may be read while still preserving the mark. An attempt to reset the stream after reading characters up to this limit or beyond may fail. A limit value larger than the size of the input buffer will cause a new buffer to be allocated whose size is no smaller than limit. Therefore large values should be used with care.
IllegalArgumentException- If readAheadLimit is < 0
IOException- If an I/O error occurs
public void reset() throws IOExceptionResets the stream to the most recent mark.