public class

DigestInputStream

extends FilterInputStream

java.lang.Object
↳	java.io.InputStream
	↳	java.io.FilterInputStream
		↳	java.security.DigestInputStream

Class Overview

DigestInputStream is a FilterInputStream which maintains an associated message digest.

Summary

Fields
protected MessageDigest	digest	The message digest for this stream.

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Inherited Fields

From class java.io.FilterInputStream

Public Constructors
	DigestInputStream(InputStream stream, MessageDigest digest) Constructs a new instance of this `DigestInputStream`, using the given `stream` and the `digest`.

Public Methods
MessageDigest	getMessageDigest() Returns the message digest for this stream.
void	on(boolean on) Enables or disables the digest function (default is on).
int	read() Reads the next byte and returns it as an `int`.
int	read(byte[] b, int off, int len) Reads `len` bytes into the specified `byte[]`, starting from the specified offset.
void	setMessageDigest(MessageDigest digest) Sets the message digest which this stream will use.
String	toString() Returns a string containing a concise, human-readable description of this `DigestInputStream` including the digest.

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Inherited Methods

From class java.io.FilterInputStream

int	available() Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void	close() Closes this stream.
synchronized void	mark(int readlimit) Sets a mark position in this stream.
boolean	markSupported() Indicates whether this stream supports `mark()` and `reset()`.
int	read(byte[] buffer) Reads bytes from this stream and stores them in the byte array `buffer`.
int	read() Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255.
int	read(byte[] buffer, int offset, int count) Reads at most `count` bytes from this stream and stores them in the byte array `buffer` starting at `offset`.
synchronized void	reset() Resets this stream to the last marked location.
long	skip(long count) Skips `count` number of bytes in this stream.

From class java.io.InputStream

int	available() Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void	close() Closes this stream.
void	mark(int readlimit) Sets a mark position in this InputStream.
boolean	markSupported() Indicates whether this stream supports the `mark()` and `reset()` methods.
int	read(byte[] b) Reads bytes from this stream and stores them in the byte array `b`.
abstract int	read() Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
int	read(byte[] b, int offset, int length) Reads at most `length` bytes from this stream and stores them in the byte array `b` starting at `offset`.
synchronized void	reset() Resets this stream to the last marked location.
long	skip(long byteCount) Skips at most `n` bytes in this stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Called before the object's memory is reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface java.io.Closeable

Fields

protected MessageDigest digest

Since: API Level 1

The message digest for this stream.

Public Constructors

public DigestInputStream (InputStream stream, MessageDigest digest)

Since: API Level 1

Constructs a new instance of this DigestInputStream, using the given stream and the digest.

Warning: passing a null source creates an invalid DigestInputStream. All operations on such a stream will fail.

Parameters

stream	the input stream.
digest	the message digest.

Public Methods

public MessageDigest getMessageDigest ()

Since: API Level 1

Returns the message digest for this stream.

Returns

the message digest for this stream.

public void on (boolean on)

Since: API Level 1

Enables or disables the digest function (default is on).

Parameters

on	`true` if the digest should be computed, `false` otherwise.

public int read ()

Since: API Level 1

Reads the next byte and returns it as an int. Updates the digest for the byte if this function is on(boolean).

This operation is blocking.

Returns

the byte which was read or -1 at end of stream.

Throws

IOException	if reading the source stream causes an `IOException`.

public int read (byte[] b, int off, int len)

Since: API Level 1

Reads len bytes into the specified byte[], starting from the specified offset. Updates the digest if this function is on(boolean).

This operation is blocking.

Parameters

b	the byte array in which to store the bytes
off	the initial position in `b` to store the bytes read from this stream
len	the maximum number of bytes to store in `b`

Returns

the number of bytes actually read or -1 if the end of the filtered stream has been reached while reading

Throws

IOException	if reading the source stream causes an `IOException`

public void setMessageDigest (MessageDigest digest)

Since: API Level 1

Sets the message digest which this stream will use.

Parameters

digest	the message digest which this stream will use.

public String toString ()

Since: API Level 1

Returns a string containing a concise, human-readable description of this DigestInputStream including the digest.

Returns

a printable representation for this DigestInputStream.

Interfaces

Classes

Enums

Exceptions

DigestInputStream

Class Overview

Summary

Fields

protected MessageDigest digest

Public Constructors

public DigestInputStream (InputStream stream, MessageDigest digest)

Parameters

Public Methods

public MessageDigest getMessageDigest ()

Returns

public void on (boolean on)

Parameters

See Also

public int read ()

Returns

Throws

public int read (byte[] b, int off, int len)

Parameters

Returns

Throws

public void setMessageDigest (MessageDigest digest)

Parameters

public String toString ()

Returns