Class DigestOutputStream
- java.lang.Object
-
- java.io.OutputStream
-
- java.io.FilterOutputStream
-
- java.security.DigestOutputStream
- All Implemented Interfaces:
-
Closeable
,Flushable
,AutoCloseable
public class DigestOutputStream extends FilterOutputStream
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 output 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.
- Since:
- 1.2
- See Also:
-
MessageDigest
,DigestInputStream
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected MessageDigest | digest | The message digest associated with this stream. |
Fields declared in class java.io.FilterOutputStream
out
Constructor Summary
Constructor | Description |
---|---|
DigestOutputStream(OutputStream stream,
MessageDigest digest) | Creates a digest output stream, using the specified output stream and message digest. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
MessageDigest | getMessageDigest() | Returns the message digest associated with this stream. |
void | on(boolean on) | Turns the digest function on or off. |
void | setMessageDigest(MessageDigest digest) | Associates the specified message digest with this stream. |
String | toString() | Prints a string representation of this digest output stream and its associated message digest object. |
void | write(byte[] b,
int off,
int 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. |
void | write(int 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. |
Methods declared in class java.io.FilterOutputStream
close, flush, write
Methods declared in class java.io.OutputStream
nullOutputStream
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Field Detail
digest
protected MessageDigest digest
The message digest associated with this stream.
Constructor Detail
DigestOutputStream
public DigestOutputStream(OutputStream stream, MessageDigest 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.
Method Detail
getMessageDigest
public MessageDigest getMessageDigest()
Returns the message digest associated with this stream.
- Returns:
- the message digest associated with this stream.
- See Also:
setMessageDigest(java.security.MessageDigest)
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. - See Also:
getMessageDigest()
write
public void write(int b) throws IOException
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.
- Overrides:
-
write
in classFilterOutputStream
- Parameters:
-
b
- the byte to be used for updating and writing to the output stream. - Throws:
-
IOException
- if an I/O error occurs. - See Also:
MessageDigest.update(byte)
write
public void write(byte[] b, int off, int len) throws IOException
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.
- Overrides:
-
write
in classFilterOutputStream
- Parameters:
-
b
- the array containing the subarray to be used for updating and writing to the output stream. -
off
- the offset intob
of the first byte to be updated and written. -
len
- the number of bytes of data to be updated and written fromb
, starting at offsetoff
. - Throws:
-
IOException
- if an I/O error occurs. - See Also:
MessageDigest.update(byte[], int, int)
on
public void on(boolean 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.
- 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 output stream and its associated message digest object.