Closeable, AutoCloseable
public class DigestInputStream extends FilterInputStream
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 one of the read 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.
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.
read methods, transferTo, readAllBytes, and readNBytes. Please note that data bypassed by the skip method are ignored. On the other hand, if the underlying stream supports the mark and reset methods, and the same data is read again after reset, then the message digest is updated again.| Modifier and Type | Field | Description |
|---|---|---|
protected MessageDigest |
digest |
The message digest associated with this stream. |
in
| Constructor | Description |
|---|---|
DigestInputStream |
Creates a digest input stream, using the specified input stream and message digest. |
| Modifier and Type | Method | Description |
|---|---|---|
MessageDigest |
getMessageDigest() |
Returns the message digest associated with this stream. |
void |
on |
Turns the digest function on or off. |
int |
read() |
Reads a byte, and updates the message digest (if the digest function is on). |
int |
read |
Reads into a byte array, and updates the message digest (if the digest function is on). |
void |
setMessageDigest |
Associates the specified message digest with this stream. |
String |
toString() |
Prints a string representation of this digest input stream and its associated message digest object. |
available, close, mark, markSupported, read, reset, skip
nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo
protected MessageDigest digest
public DigestInputStream(InputStream stream, MessageDigest digest)
stream - the input stream.digest - the message digest to associate with this stream.public MessageDigest getMessageDigest()
public void setMessageDigest(MessageDigest digest)
digest - the message digest to be associated with this stream.public int read() throws IOException
on), this method will then call update on the message digest associated with this stream, passing it the byte read.read in class FilterInputStream
IOException - if an I/O error occurs.public int read(byte[] b, int off, int len) throws IOException
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.read in class FilterInputStream
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.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.IOException - if an I/O error occurs.public void on(boolean on)
read methods results in an update on the message digest. But when it is off, the message digest is not updated.on - true to turn the digest function on, false to turn it off.public String toString()
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/security/DigestInputStream.html