java.security
public class: DigestOutputStream [javadoc |
source]
java.lang.Object
java.io.OutputStream
java.io.FilterOutputStream
java.security.DigestOutputStream
All Implemented Interfaces:
Flushable, Closeable
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 ouput stream's
write methods.
It is possible to turn this stream on or off (see
on ). When it is on, a call to one of the
write methods 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.
| Field Summary |
|---|
| protected MessageDigest | digest | The message digest associated with this stream. |
| Constructor: |
|---|
 public DigestOutputStream(OutputStream stream,
MessageDigest digest) {
super(stream);
setMessageDigest(digest);
}
Creates a digest output stream, using the specified output stream
and message digest. Parameters:
stream - the output stream.
digest - the message digest to associate with this stream.
|
| Methods from java.lang.Object: |
|---|
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Method from java.security.DigestOutputStream Detail: |
|---|
public MessageDigest getMessageDigest() {
return digest;
} Returns the message digest associated with this stream. |
public void on(boolean on) {
this.on = on;
} Turns the digest function on or off. The default is on. When
it is on, a call to one of the write methods results in an
update on the message digest. But when it is off, the message
digest is not updated. |
public void setMessageDigest(MessageDigest digest) {
this.digest = digest;
} Associates the specified message digest with this stream. |
public String toString() {
return "[Digest Output Stream] " + digest.toString();
} Prints a string representation of this digest output stream and
its associated message digest object. |
public void write(int b) throws IOException {
if (on) {
digest.update((byte)b);
}
out.write(b);
} Updates the message digest (if the digest function is on) using
the specified byte, and in any case writes the byte
to the output stream. That is, if the digest function is on
(see on ), this method calls
update on the message digest associated with this
stream, passing it the byte b. This method then
writes the byte to the output stream, blocking until the byte
is actually written. |
public void write(byte[] b,
int off,
int len) throws IOException {
if (on) {
digest.update(b, off, len);
}
out.write(b, off, len);
} Updates the message digest (if the digest function is on) using
the specified subarray, and in any case writes the subarray to
the output stream. That is, if the digest function is on (see
on ), this method calls update
on the message digest associated with this stream, passing it
the subarray specifications. This method then writes the subarray
bytes to the output stream, blocking until the bytes are actually
written. |