Class au.net.aba.security.DigestInputStream
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Class au.net.aba.security.DigestInputStream
java.lang.Object
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+----java.io.InputStream
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+----java.io.FilterInputStream
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+----au.net.aba.security.DigestInputStream
- public class DigestInputStream
- extends FilterInputStream
A transparent stream that updates the associated message digest
using the bits going through the stream.
To complete the message digest computation, call one of the
digest methods on the associated message digest after your calls to
one of this digest input stream's read methods.
It is possible to turn this stream on or off (see on). When it
is on, a call to read results in an update on the message digest.
But when it is off, the message digest is not updated. The default
is for the stream to be on.
Note that digest objects can compute only one digest (see
MessageDigest), so that in order to compute intermediate digests, a
caller should retain a handle onto the digest object, and clone it
for each digest to be computed, leaving the original digest
untouched.
- See Also:
- MessageDigest, DigestOutputStream
-
digest
- The message digest associated with this stream.
-
ident
-
-
DigestInputStream(InputStream, MessageDigest)
- Creates a digest input stream, using the specified input stream
and message digest.
-
getMessageDigest()
- Returns the message digest associated with this stream.
-
on(boolean)
- Turns the digest function on or off.
-
read()
- Reads a byte, and updates the message digest (if the digest
function is on).
-
read(byte[], int, int)
- Reads into a byte array, and updates the message digest (if the
digest function is on).
-
setMessageDigest(MessageDigest)
- Associates the specified message digest with this stream.
-
toString()
- Prints a string representation of this digest input stream and
its associated message digest object.
ident
public final static String ident
digest
protected MessageDigest digest
- The message digest associated with this stream.
DigestInputStream
public DigestInputStream(InputStream stream,
MessageDigest digest)
- Creates a digest input stream, using the specified input stream
and message digest.
- Parameters:
- stream - - the input stream.
- digest - - the message digest to associate with this stream.
getMessageDigest
public MessageDigest getMessageDigest()
- Returns the message digest associated with this stream.
- Returns:
- the message digest associated with this stream.
setMessageDigest
public void setMessageDigest(MessageDigest digest)
- Associates the specified message digest with this stream.
- Parameters:
- digest - - the message digest to be associated with this stream.
read
public int read() throws IOException
- Reads a byte, and updates the message digest (if the digest
function is on). That is, this method reads a byte from the
input stream, blocking until the byte is actually read. If the
digest function is on (see on), this method will then call
update on the message digest associated with this stream,
passing it the byte read.
- Returns:
- s the byte read.
- Throws: IOException
- if an I/O error occurs.
- Overrides:
- read in class FilterInputStream
- See Also:
- update
read
public int read(byte b[],
int off,
int len) throws IOException
- Reads into a byte array, and updates the message digest (if the
digest function is on). That is, this method reads up to len
bytes from the input stream into the array b, starting at offset
off. This method blocks until the data is actually read. If the
digest function is on (see on), this method will then call
update on the message digest associated with this stream,
passing it the data.
- Parameters:
- b - - the array into which the data is read.
- off - - the starting offset into b of where the data should
be placed.
- len - - the maximum number of bytes to be read from the
input stream into b, starting at offset off.
- Returns:
- the actual number of bytes read. This is less than len
if the end of the stream is reached prior to reading len bytes.
-1 is returned if no bytes were read because the end of the
stream had already been reached when the call was made
- Throws: IOException
- if an I/O error occurs.
- Overrides:
- read in class FilterInputStream
- See Also:
- update
on
public void on(boolean on)
- Turns the digest function on or off. The default is on. When it
is on, a call to read results in an update on the message
digest. But when it is off, the message digest is not updated.
- Parameters:
- on - - true to turn the digest function on, false to turn it off.
toString
public String toString()
- Prints a string representation of this digest input stream and
its associated message digest object.
- Overrides:
- toString in class Object
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