com.captainalm.lib.calmnet.stream

Class LengthClampedInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

com.captainalm.lib.calmnet.stream.LengthClampedInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class LengthClampedInputStream
extends java.io.FilterInputStream

This class provides the ability to limit the number of bytes read from the underlying stream. When the limit is reached, this class considers that state as end of stream.

Author:

Captain ALM

Constructor Summary

Constructors

Constructor and Description
LengthClampedInputStream(java.io.InputStream inputStream, int length) Creates a LengthClampedInputStream with the specified InputStream and the maximum number of bytes that can be read from the stream.

Method Summary

Modifier and Type	Method and Description
int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
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.
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
void	setClampedLength(int clampedLength) Sets a new clamped length value.

Methods inherited from class java.io.FilterInputStream

markSupported, read, read, skip

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LengthClampedInputStream

public LengthClampedInputStream(java.io.InputStream inputStream,
                                int length)

Creates a LengthClampedInputStream with the specified InputStream and the maximum number of bytes that can be read from the stream.

Parameters:

inputStream - The input stream to clamp.

length - The maximum number of bytes that can be read before end of stream is reached.

Throws:

java.lang.NullPointerException - inputStream is null.

java.lang.IllegalArgumentException - length is less than 0.

Method Detail

read

public int read()
         throws java.io.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.

Overrides:

read in class java.io.FilterInputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs.

available

public int available()
              throws java.io.IOException

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Overrides:

available in class java.io.FilterInputStream

Returns:

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.

Throws:

java.io.IOException - if an I/O error occurs.

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.

Overrides:

mark in class java.io.FilterInputStream

Parameters:

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

reset

public void reset()
           throws java.io.IOException

Repositions this stream to the position at the time the mark method was last called on this 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 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 java.io.FilterInputStream

Throws:

java.io.IOException - if the stream has not been marked, if the mark has been invalidated or marking is not supported.

close

public void close()
           throws java.io.IOException

Closes this input stream and releases any system resources associated with the stream.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.FilterInputStream

Throws:

java.io.IOException - if an I/O error occurs.

setClampedLength

public void setClampedLength(int clampedLength)

Sets a new clamped length value. This is the maximum number of bytes that can be read from the stream.

Parameters:

clampedLength - The new clamped length value.

Throws:

java.lang.IllegalArgumentException - clampedLength is less than 0.