package java.io;
/**
+ * This class functions like a standard <code>Reader</code> except that it
+ * counts line numbers, and canonicalizes newline characters. As data
+ * is read, whenever the char sequences "\r", "\n", or "\r\n" are encountered,
+ * the running line count is incremeted by one. Additionally, the whatever
+ * line termination sequence was encountered will be converted to a "\n"
+ * char. Note that this class numbers lines from 0. When the first
+ * line terminator is encountered, the line number is incremented to 1, and
+ * so on. Also note that actual "\r" and "\n" characters are looked for.
+ * The system dependent line separator sequence is ignored.
+ * <p>
+ * This class counts only line termination characters. If the last line
+ * read from the stream does not end in a line termination sequence, it
+ * will not be counted as a line.
+ *
* @author Per Bothner <bothner@cygnus.com>
+ * @author Aaron M. Renn (arenn@urbanophile.com)
* @date April 22, 1998.
*/
/* Written using "Java Class Libraries", 2nd edition, plus online
*
* This implementation is also minimal in the number of fields it uses.
*/
-
public class LineNumberReader extends BufferedReader
{
/** The current line number. */
int lineNumber;
+ /**
+ * Create a new <code>LineNumberReader</code> that reads from the
+ * specified subordinate <code>Reader</code>. A default 8K char sized
+ * buffer will be used for reads.
+ *
+ * @param in The subordinate <code>Reader</code> to read from
+ */
public LineNumberReader(Reader in)
{
super(in, 8192);
}
+ /**
+ * This method initializes a new <code>LineNumberReader</code> to read
+ * from the specified subordinate <code>Reader</code> using the specified
+ * read buffer size.
+ *
+ * @param in The subordinate <code>Reader</code> to read from
+ * @param size The buffer size to use for reading
+ */
public LineNumberReader(Reader in, int size)
{
super(in, size);
}
+ /**
+ * This method returns the current line number
+ *
+ * @returns The current line number
+ */
public int getLineNumber()
{
return lineNumber;
}
+ /**
+ * This method sets the current line number to the specified value.
+ *
+ * @param line_number The new line number
+ */
public void setLineNumber(int lineNumber)
{
this.lineNumber = lineNumber;
return count;
}
+ /**
+ * This method marks a position in the input to which the stream can be
+ * "reset" char calling the <code>reset()</code> method. The parameter
+ * <code>readlimit</code> is the number of chars that can be read from the
+ * stream after setting the mark before the mark becomes invalid. For
+ * example, if <code>mark()</code> is called with a read limit of 10,
+ * then when
+ * 11 chars of data are read from the stream before the <code>reset()</code>
+ * method is called, then the mark is invalid and the stream object
+ * instance is not required to remember the mark.
+ * <p>
+ * In this class, this method will remember the current line number as well
+ * as the current position in the stream. When the <code>reset()</code>
+ * method
+ * is called, the line number will be restored to the saved line number in
+ * addition to the stream position.
+ *
+ * @param readlimit The number of chars that can be read before the
+ * mark becomes invalid
+ *
+ * @exception IOException If an error occurs
+ */
public void mark(int readLimit) throws IOException
{
synchronized (lock)
}
}
+ /**
+ * This method resets a stream to the point where the <code>mark()</code>
+ * method
+ * was called. Any chars that were read after the mark point was set will
+ * be re-read during subsequent reads.
+ * <p>
+ * In this class, this method will also restore the line number that was
+ * current when the <code>mark()</code> method was called.
+ *
+ * @exception IOException If an error occurs
+ */
public void reset() throws IOException
{
synchronized (lock)
}
}
+ /**
+ * This method reads an unsigned char from the input stream and returns it
+ * as an int in the range of 0-65535. This method will return -1 if the
+ * end of the stream has been reached.
+ * <p>
+ * Note that if a line termination sequence is encountered (ie, "\r",
+ * "\n", or "\r\n") then that line termination sequence is converted to
+ * a single "\n" value which is returned from this method. This means
+ * that it is possible this method reads two chars from the subordinate
+ * stream instead of just one.
+ * <p>
+ * Note that this method will block until a char of data is available
+ * to be read.
+ *
+ * @return The char read or -1 if end of stream
+ *
+ * @exception IOException If an error occurs
+ */
public int read() throws IOException
{
synchronized (lock)
}
}
+ /**
+ * This method reads chars from a stream and stores them into a caller
+ * supplied buffer. It starts storing data at index <code>offset</code> into * the buffer and attemps to read <code>len</code> 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 indicated the
+ * end of the stream.
+ * <p>
+ * This method will block until some data can be read.
+ * <p>
+ * Note that if a line termination sequence is encountered (ie, "\r",
+ * "\n", or "\r\n") then that line termination sequence is converted to
+ * a single "\n" value which is stored in the buffer. Only a single
+ * char is counted towards the number of chars read in this case.
+ *
+ * @param buf The array into which the chars read should be stored
+ * @param offset The offset into the array to start storing chars
+ * @param len The requested number of chars to read
+ *
+ * @return The actual number of chars read, or -1 if end of stream
+ *
+ * @exception IOException If an error occurs.
+ */
public int read(char[] buf, int offset, int count) throws IOException
{
if (count <= 0)
}
}
+ /**
+ * This method reads a line of text from the input stream and returns
+ * it as a <code>String</code>. A line is considered to be terminated
+ * by a "\r", "\n", or "\r\n" sequence, not by the system dependent line
+ * separator.
+ *
+ * @return The line read as a <code>String</code> or <code>null</code>
+ * if end of stream.
+ *
+ * @exception IOException If an error occurs
+ */
public String readLine() throws IOException
{
// BufferedReader.readLine already does this. Shouldn't need to keep
return str;
}
+ /**
+ * This method skips over characters in the stream. This method will
+ * skip the specified number of characters if possible, but is not required
+ * to skip them all. The actual number of characters skipped is returned.
+ * This method returns 0 if the specified number of chars is less than 1.
+ *
+ * @param count The specified number of chars to skip.
+ *
+ * @return The actual number of chars skipped.
+ *
+ * @exception IOException If an error occurs
+ */
public long skip(long count) throws IOException
{
if (count <= 0)
return count - to_do;
}
}
+
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