Class LineNumberInputStream
- java.lang.Object
-
- java.io.InputStream
-
- java.io.FilterInputStream
-
- java.io.LineNumberInputStream
- All Implemented Interfaces:
-
Closeable
,AutoCloseable
@Deprecated public class LineNumberInputStream extends FilterInputStream
This class is an input stream filter that provides the added functionality of keeping track of the current line number.
A line is a sequence of bytes ending with a carriage return character ('\r'
), a newline character ('\n'
), or a carriage return character followed immediately by a linefeed character. In all three cases, the line terminating character(s) are returned as a single newline character.
The line number begins at 0
, and is incremented by 1
when a read
returns a newline character.
- Since:
- 1.0
- See Also:
LineNumberReader
Field Summary
Fields declared in class java.io.FilterInputStream
in
Constructor Summary
Constructor | Description |
---|---|
LineNumberInputStream(InputStream in) | Deprecated. Constructs a newline number input stream that reads its input from the specified input stream. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
int | available() | Deprecated. Returns the number of bytes that can be read from this input stream without blocking. |
int | getLineNumber() | Deprecated. Returns the current line number. |
void | mark(int readlimit) | Deprecated. Marks the current position in this input stream. |
int | read() | Deprecated. Reads the next byte of data from this input stream. |
int | read(byte[] b,
int off,
int len) | Deprecated. Reads up to |
void | reset() | Deprecated. Repositions this stream to the position at the time the |
void | setLineNumber(int lineNumber) | Deprecated. Sets the line number to the specified argument. |
long | skip(long n) | Deprecated. Skips over and discards |
Methods declared in class java.io.FilterInputStream
close, markSupported, read
Methods declared in class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
LineNumberInputStream
public LineNumberInputStream(InputStream in)
Constructs a newline number input stream that reads its input from the specified input stream.
- Parameters:
-
in
- the underlying input stream.
Method Detail
read
public int read() throws IOException
Reads the next byte of data from this input stream. The value byte is returned as an int
in the range 0
to 255
. If no byte is available because the end of the stream has been reached, the value -1
is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
The read
method of LineNumberInputStream
calls the read
method of the underlying input stream. It checks for carriage returns and newline characters in the input, and modifies the current line number as appropriate. A carriage-return character or a carriage return followed by a newline character are both converted into a single newline character.
- Overrides:
-
read
in classFilterInputStream
- Returns:
- the next byte of data, or
-1
if the end of this stream is reached. - Throws:
-
IOException
- if an I/O error occurs. - See Also:
-
FilterInputStream.in
,getLineNumber()
read
public int read(byte[] b, int off, int len) throws IOException
Reads up to len
bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
The read
method of LineNumberInputStream
repeatedly calls the read
method of zero arguments to fill in the byte array.
- Overrides:
-
read
in classFilterInputStream
- Parameters:
-
b
- the buffer into which the data is read. -
off
- the start offset of the data. -
len
- the maximum number of bytes read. - Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of this stream has been reached. - Throws:
-
IOException
- if an I/O error occurs. - See Also:
read()
skip
public long skip(long n) throws IOException
Skips over and discards n
bytes of data from this input stream. The skip
method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0
. The actual number of bytes skipped is returned. If n
is negative, no bytes are skipped.
The skip
method of LineNumberInputStream
creates a byte array and then repeatedly reads into it until n
bytes have been read or the end of the stream has been reached.
- Overrides:
-
skip
in classFilterInputStream
- Parameters:
-
n
- the number of bytes to be skipped. - Returns:
- the actual number of bytes skipped.
- Throws:
-
IOException
- if an I/O error occurs. - See Also:
FilterInputStream.in
setLineNumber
public void setLineNumber(int lineNumber)
Sets the line number to the specified argument.
- Parameters:
-
lineNumber
- the new line number. - See Also:
getLineNumber()
getLineNumber
public int getLineNumber()
Returns the current line number.
- Returns:
- the current line number.
- See Also:
setLineNumber(int)
available
public int available() throws IOException
Returns the number of bytes that can be read from this input stream without blocking.
Note that if the underlying input stream is able to supply k input characters without blocking, the LineNumberInputStream
can guarantee only to provide k/2 characters without blocking, because the k characters from the underlying input stream might consist of k/2 pairs of '\r'
and '\n'
, which are converted to just k/2 '\n'
characters.
- Overrides:
-
available
in classFilterInputStream
- Returns:
- the number of bytes that can be read from this input stream without blocking.
- Throws:
-
IOException
- if an I/O error occurs. - See Also:
FilterInputStream.in
mark
public void mark(int readlimit)
Marks the current position in this input stream. A subsequent call to the reset
method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.
The mark
method of LineNumberInputStream
remembers the current line number in a private variable, and then calls the mark
method of the underlying input stream.
- Overrides:
-
mark
in classFilterInputStream
- Parameters:
-
readlimit
- the maximum limit of bytes that can be read before the mark position becomes invalid. - See Also:
-
FilterInputStream.in
,reset()
reset
public void reset() throws IOException
Repositions this stream to the position at the time the mark
method was last called on this input stream.
The reset
method of LineNumberInputStream
resets the line number to be the line number at the time the mark
method was called, and then calls the reset
method of the underlying input stream.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails, which, if it happens within readlimit bytes, allows the outer code to reset the stream and try another parser.
- Overrides:
-
reset
in classFilterInputStream
- Throws:
-
IOException
- if an I/O error occurs. - See Also:
-
FilterInputStream.in
,mark(int)