public class CipherInputStream extends FilterInputStream
For example, if the Cipher is initialized for decryption, the CipherInputStream will attempt to read in data and decrypt them, before returning the decrypted data.
This class adheres strictly to the semantics, especially the
failure semantics, of its ancestor classes
java.io.FilterInputStream and java.io.InputStream. This class has
exactly those methods specified in its ancestor classes, and
overrides them all. Moreover, this class catches all exceptions
that are not thrown by its ancestor classes. In particular, the
skip
method skips, and the available
method counts only data that have been processed by the encapsulated Cipher.
It is crucial for a programmer using this class not to use methods that are not defined or overriden in this class (such as a new method or constructor that is later added to one of the super classes), because the design and implementation of those methods are unlikely to have considered security impact with regard to CipherInputStream.
InputStream
,
FilterInputStream
,
Cipher
,
CipherOutputStream
in
Modifier | Constructor and Description |
---|---|
protected |
CipherInputStream(InputStream is)
Constructs a CipherInputStream from an InputStream without
specifying a Cipher.
|
|
CipherInputStream(InputStream is,
Cipher c)
Constructs a CipherInputStream from an InputStream and a
Cipher.
|
Modifier and Type | Method and Description |
---|---|
int |
available()
Returns the number of bytes that can be read from this input
stream without blocking.
|
void |
close()
Closes this input stream and releases any system resources
associated with the stream.
|
boolean |
markSupported()
Tests if this input stream supports the
mark
and reset methods, which it does not. |
int |
read()
Reads the next byte of data from this input stream.
|
int |
read(byte[] b)
Reads up to
b.length bytes of data from this input
stream into an array of bytes. |
int |
read(byte[] b,
int off,
int len)
Reads up to
len bytes of data from this input stream
into an array of bytes. |
long |
skip(long n)
Skips
n bytes of input from the bytes that can be read
from this input stream without blocking. |
mark, reset
public CipherInputStream(InputStream is, Cipher c)
is
- the to-be-processed input streamc
- an initialized Cipher objectprotected CipherInputStream(InputStream is)
is
- the to-be-processed input streampublic int read() throws IOException
int
in the range
0
to 255
. If no byte is available
because the end of the stream has been reached, the value
-1
is returned. This method blocks until input data
is available, the end of the stream is detected, or an exception
is thrown.
read
in class FilterInputStream
-1
if the end of the
stream is reached.IOException
- if an I/O error occurs.FilterInputStream.in
public int read(byte[] b) throws IOException
b.length
bytes of data from this input
stream into an array of bytes.
The read
method of InputStream
calls
the read
method of three arguments with the arguments
b
, 0
, and b.length
.
read
in class FilterInputStream
b
- the buffer into which the data is read.-1
is there is no more data because the end of
the stream has been reached.IOException
- if an I/O error occurs.InputStream.read(byte[], int, int)
public int read(byte[] b, int off, int len) throws IOException
len
bytes of data from this input stream
into an array of bytes. This method blocks until some input is
available. If the first argument is null,
up to
len
bytes are read and discarded.read
in class FilterInputStream
b
- the buffer into which the data is read.off
- the start offset in the destination array
buf
len
- the maximum number of bytes read.-1
if there is no more data because the end of
the stream has been reached.IOException
- if an I/O error occurs.InputStream.read()
public long skip(long n) throws IOException
n
bytes of input from the bytes that can be read
from this input stream without blocking.
Fewer bytes than requested might be skipped.
The actual number of bytes skipped is equal to n
or
the result of a call to
available
,
whichever is smaller.
If n
is less than zero, no bytes are skipped.
The actual number of bytes skipped is returned.
skip
in class FilterInputStream
n
- the number of bytes to be skipped.IOException
- if an I/O error occurs.public int available() throws IOException
available
method of
InputStream
returns 0
. This method
should be overridden by subclasses.available
in class FilterInputStream
IOException
- if an I/O error occurs.public void close() throws IOException
The close
method of CipherInputStream
calls the close
method of its underlying input
stream.
close
in interface Closeable
close
in interface AutoCloseable
close
in class FilterInputStream
IOException
- if an I/O error occurs.FilterInputStream.in
public boolean markSupported()
mark
and reset
methods, which it does not.markSupported
in class FilterInputStream
false
, since this class does not support the
mark
and reset
methods.InputStream.mark(int)
,
InputStream.reset()
Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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