Project JXTA

net.jxta.util
Class LimitInputStream

java.lang.Object
  extended by java.io.InputStream
      extended by java.io.FilterInputStream
          extended by net.jxta.util.LimitInputStream
All Implemented Interfaces:
Closeable

public class LimitInputStream
extends FilterInputStream

Implements a bounds on the number of bytes which may be read from an InputStream. {link LimitInputStream.close() close()} does not close the underlying stream.


Field Summary
 
Fields inherited from class java.io.FilterInputStream
in
 
Constructor Summary
LimitInputStream(InputStream in, long limit)
          Creates a new instance of LimitInputStream
LimitInputStream(InputStream in, long limit, boolean underflowThrows)
          Creates a new instance of LimitInputStream
 
Method Summary
 int available()
          Returns the number of bytes that can be read from this input stream without blocking.
 void close()
          Closes this input stream and releases any system resources associated with the stream.
 void mark(int readlimit)
          Marks the current position in this input stream.
 int read()
          Reads the next byte of data from this input stream.
 int read(byte[] b, int off, int len)
          Reads up to len bytes of data from this input stream into an array of bytes.
 void reset()
          Repositions this stream to the position at the time the mark method was last called on this input stream.
 long skip(long n)
          Skips over and discards n bytes of data from the input stream.
 String toString()
          

Debugging toString.

 
Methods inherited from class java.io.FilterInputStream
markSupported, read
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

LimitInputStream

public LimitInputStream(InputStream in,
                        long limit)
Creates a new instance of LimitInputStream

Parameters:
in - the stream which will be limited.
limit - the number of bytes which can be read from the stream.

LimitInputStream

public LimitInputStream(InputStream in,
                        long limit,
                        boolean underflowThrows)
Creates a new instance of LimitInputStream

Parameters:
in - the stream which will be limited.
limit - the number of bytes which can be read from the stream.
underflowThrows - if the underlying stream EOFs before limit then an IOException will be thrown.
Method Detail

toString

public String toString()

Debugging toString.

Overrides:
toString in class Object

close

public void close()
           throws IOException
Closes this input stream and releases any system resources associated with the stream.

This method simply forgets the underlying stream.

Specified by:
close in interface Closeable
Overrides:
close in class FilterInputStream
Throws:
IOException - if an I/O error occurs.
See Also:
FilterInputStream.in

available

public int available()
              throws IOException
Returns the number of bytes that can be read from this input stream without blocking.

This method simply performs in.available(n) and returns the result.

Overrides:
available in class FilterInputStream
Returns:
the number of bytes that can be read from the 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 readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

This method simply performs in.mark(readlimit).

Overrides:
mark in class FilterInputStream
Parameters:
readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
See Also:
FilterInputStream.in, FilterInputStream.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.

This method simply performs in.reset().

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 parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.

Overrides:
reset in class FilterInputStream
Throws:
IOException - if the stream has not been marked or if the mark has been invalidated.
See Also:
FilterInputStream.in, FilterInputStream.mark(int)

skip

public long skip(long n)
          throws IOException
Skips over and discards n bytes of data from the 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.

This method simply performs in.skip(n).

Overrides:
skip in class FilterInputStream
Parameters:
n - the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws:
IOException - if an I/O error occurs.

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.

This method simply performs in.read() and returns the result.

Overrides:
read in class FilterInputStream
Returns:
the next byte of data, or -1 if the end of the stream is reached.
Throws:
IOException - if an I/O error occurs.
See Also:
FilterInputStream.in

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.

This method simply performs in.read(b, off, len) and returns the result.

Overrides:
read in class FilterInputStream
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 the stream has been reached.
Throws:
IOException - if an I/O error occurs.
See Also:
FilterInputStream.in

JXTA J2SE