CheckedInputStream

AI-generated Key Takeaways

• CheckedInputStream is used to maintain a checksum of data being read from an input stream for data integrity verification.

• It uses a Checksum object to calculate and store the checksum value.

• CheckedInputStream provides methods for reading data, skipping bytes, and retrieving the calculated checksum.

• It inherits functionalities from FilterInputStream, allowing it to wrap and enhance an existing input stream.

public class CheckedInputStream extends FilterInputStream

An input stream that also maintains a checksum of the data being read. The checksum can then be used to verify the integrity of the input data.

See Also

• Checksum

Inherited Field Summary

From class java.io.FilterInputStream

protected InputStream

in

The input stream to be filtered.

Public Constructor Summary

CheckedInputStream(InputStream in, Checksum cksum) Creates an input stream using the specified Checksum.

Public Method Summary

Checksum	getChecksum() Returns the Checksum for this input stream.
int	read() Reads a byte.
int	read(byte[] buf, int off, int len) Reads into an array of bytes.
long	skip(long n) Skips specified number of bytes of input.

Inherited Method Summary

From class java.io.FilterInputStream

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.
synchronized void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
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.
int	read(byte[] b) Reads up to byte.length bytes of data from this input stream into an array of bytes.
synchronized 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.

From class java.io.InputStream

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 invocation of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
abstract int	read() Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
synchronized 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 this input stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.io.Closeable

abstract void

close() Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Public Constructors

public CheckedInputStream (InputStream in, Checksum cksum)

Creates an input stream using the specified Checksum.

Parameters

in	the input stream
cksum	the Checksum

Public Methods

public Checksum getChecksum ()

Returns the Checksum for this input stream.

Returns

• the Checksum value

public int read ()

Reads a byte. Will block if no input is available.

Returns

• the byte read, or -1 if the end of the stream is reached.

Throws

IOException	if an I/O error has occurred

public int read (byte[] buf, int off, int len)

Reads into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned.

Parameters

buf	the buffer into which the data is read
off	the start offset in the destination array b
len	the maximum number of bytes read

Returns

• the actual number of bytes read, or -1 if the end of the stream is reached.

Throws

NullPointerException	If buf is null.
IndexOutOfBoundsException	If off is negative, len is negative, or len is greater than buf.length - off
IOException	if an I/O error has occurred

public long skip (long n)

Skips specified number of bytes of input.

Parameters

n	the number of bytes to skip

Returns

• the actual number of bytes skipped

Throws

IOException	if an I/O error has occurred