Class CheckedInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.util.zip.CheckedInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

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.

Since:

1.1

See Also:

• Checksum

Field Summary

Fields declared in class FilterInputStream

in

Modifier and Type	Field	Description
protected InputStream	in	The input stream to be filtered.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
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.

Methods declared in class FilterInputStream

available, close, mark, markSupported, read, reset

Modifier and Type	Method	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.
boolean	markSupported()	Tests if this input stream supports the mark and reset methods.
int	read(byte[] b)	Reads up to b.length 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.

Methods declared in class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Modifier and Type	Method	Description
static InputStream	nullInputStream()	Returns a new InputStream that reads no bytes.
byte[]	readAllBytes()	Reads all remaining bytes from the input stream.
int	readNBytes(byte[] b, int off, int len)	Reads the requested number of bytes from the input stream into the given byte array.
byte[]	readNBytes(int len)	Reads up to a specified number of bytes from the input stream.
void	skipNBytes(long n)	Skips over and discards exactly n bytes of data from this input stream.
long	transferTo(OutputStream out)	Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

CheckedInputStream

public CheckedInputStream(InputStream in,
 Checksum cksum)

Creates an input stream using the specified Checksum.

Parameters:

in - the input stream

cksum - the Checksum

Method Details

read

public int read()
         throws IOException

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

Overrides:

read in class FilterInputStream

Returns:

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

Throws:

IOException - if an I/O error has occurred

See Also:

• FilterInputStream.in

read

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

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.

Overrides:

read in class FilterInputStream

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

See Also:

• FilterInputStream.in

skip

public long skip(long n)
          throws IOException

Skips specified number of bytes of input.

Overrides:

skip in class FilterInputStream

Parameters:

n - the number of bytes to skip

Returns:

the actual number of bytes skipped

Throws:

IOException - if an I/O error has occurred

See Also:

• InputStream.skipNBytes(long)

getChecksum

public Checksum getChecksum()

Returns the Checksum for this input stream.

Returns:

the Checksum value