| java.lang.Object | |||
| ↳ | java.io.Reader | ||
| ↳ | java.io.BufferedReader | ||
| ↳ | java.io.LineNumberReader | ||
Class Overview
A buffered character-input stream that keeps track of line numbers. This
class defines methods setLineNumber(int) and getLineNumber() for setting and getting the current line number
respectively.
By default, line numbering begins at 0. This number increments at every line terminator as the data is read, and can be changed with a call to setLineNumber(int). Note however, that setLineNumber(int) does not actually change the current position in the stream; it only changes the value that will be returned by getLineNumber().
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.
Summary
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Inherited Fields | |||||||||||
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 From class
java.io.Reader
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Create a new line-numbering reader, using the default input-buffer
size.
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Create a new line-numbering reader, reading characters into a buffer of
the given size.
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| Public Methods | |||||||||||
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Get the current line number.
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Mark the present position in the stream.
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Read a single character.
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Read characters into a portion of an array.
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Read a line of text.
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Reset the stream to the most recent mark.
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Set the current line number.
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Skip characters.
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Inherited Methods | |||||||||||
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From class
java.io.BufferedReader
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From class
java.io.Reader
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From class
java.lang.Object
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From interface
java.io.Closeable
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From interface
java.lang.Readable
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Public Constructors
public LineNumberReader (Reader in)
Create a new line-numbering reader, using the default input-buffer size.
Parameters
| in | A Reader object to provide the underlying stream |
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public LineNumberReader (Reader in, int sz)
Create a new line-numbering reader, reading characters into a buffer of the given size.
Parameters
| in | A Reader object to provide the underlying stream |
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| sz | An int specifying the size of the buffer |
Public Methods
public int getLineNumber ()
public void mark (int readAheadLimit)
Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point, and will also reset the line number appropriately.
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. |
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Throws
| IOException | If an I/O error occurs |
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public int read ()
Read a single character. Line terminators are compressed into single newline ('\n') characters. Whenever a line terminator is read the current line number is incremented.
Returns
- The character read, or -1 if the end of the stream has been reached
Throws
| IOException | If an I/O error occurs |
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public int read (char[] cbuf, int off, int len)
Read characters into a portion of an array. Whenever a line terminator is read the current line number is incremented.
Parameters
| cbuf | Destination buffer |
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| off | Offset at which to start storing characters |
| len | Maximum number of characters to read |
Returns
- The number of bytes read, or -1 if the end of the stream has already been reached
Throws
| IOException | If an I/O error occurs |
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public String readLine ()
Read a line of text. Whenever a line terminator is read the current line number is incremented.
Returns
- 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
Throws
| IOException | If an I/O error occurs |
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public void reset ()
Reset the stream to the most recent mark.
Throws
| IOException | If the stream has not been marked, or if the mark has been invalidated |
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public void setLineNumber (int lineNumber)
Set the current line number.
Parameters
| lineNumber | An int specifying the line number |
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See Also
public long skip (long n)
Skip characters.
Parameters
| n | The number of characters to skip |
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Returns
- The number of characters actually skipped
Throws
| IOException | If an I/O error occurs |
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| IllegalArgumentException | If n is negative |