gnu.crypto.assembly
Class Assembly

java.lang.Object
  gnu.crypto.assembly.Assembly

public class Assembly

extends java.lang.Object

An Assembly is a construction consisting of a chain of Transformer elements; each wired in pre- or post- transformation mode. This chain is terminated by one LoopbackTransformer element.

Once constructed, and correctly initialised, the bulk of the methods available on the Assembly are delegated to the head of the Transformer chain of the Assembly.

Version:

$Revision: 1.2 $

See Also:

Transformer

Field Summary

static java.lang.String

DIRECTION

Constructor Summary

Assembly()
Trivial constructor that sets the chain to a LoopbackTransformer.

Method Summary

void	addPostTransformer(Transformer t) Adds the designated Transformer and signals that it should operate in post-processing mode; i.e. it should apply its internal transformation algorithm on the input data stream, after it passes that stream to the next element in the chain.
void	addPreTransformer(Transformer t) Adds the designated Transformer and signals that it should operate in pre-processing mode; i.e. it should apply its internal transformation algorithm on the input data stream, before it passes that stream to the next element in the chain.
void	init(java.util.Map attributes) Initialises the Assembly for operation with specific characteristics.
byte[]	lastUpdate() Convenience method that calls the method with same name and three arguments using a 0-long byte array.
byte[]	lastUpdate(byte b) Convenience method that calls the method with same name and three arguments, using a byte array of length 1 whose contents are the designated byte.
byte[]	lastUpdate(byte[] in) Convenience method that calls the method with same name and three arguments.
byte[]	lastUpdate(byte[] in, int offset, int length) Processes a designated number of bytes from a given byte array and signals, at the same time, that this is the last push operation for this Assembly.
void	reset() Resets the Assembly for re-initialisation and use with other characteristics.
byte[]	update(byte b) Convenience method that calls the method with same name and three arguments, using a byte array of length 1 whose contents are the designated byte.
byte[]	update(byte[] in) Convenience method that calls the method with same name and three arguments.
byte[]	update(byte[] in, int offset, int length) Processes a designated number of bytes from a given byte array.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DIRECTION

public static final java.lang.String DIRECTION

See Also:

Constant Field Values

Constructor Detail

Assembly

public Assembly()

Trivial constructor that sets the chain to a LoopbackTransformer.

Method Detail

addPreTransformer

public void addPreTransformer(Transformer t)

Adds the designated Transformer and signals that it should operate in pre-processing mode; i.e. it should apply its internal transformation algorithm on the input data stream, before it passes that stream to the next element in the chain.

Parameters:

t - the Transformer to add at the head of the current chain.

Throws:

java.lang.IllegalArgumentException - if the designated Transformer has a non-null tail; i.e. it is already an element of a chain.

addPostTransformer

public void addPostTransformer(Transformer t)

Adds the designated Transformer and signals that it should operate in post-processing mode; i.e. it should apply its internal transformation algorithm on the input data stream, after it passes that stream to the next element in the chain.

Parameters:

t - the Transformer to add at the head of the current chain.

Throws:

java.lang.IllegalArgumentException - if the designated Transformer has a non-null tail; i.e. it is already an element of a chain.

init

public void init(java.util.Map attributes)
          throws TransformerException

Initialises the Assembly for operation with specific characteristics.

Parameters:

attributes - a set of name-value pairs that describes the desired future behaviour of this instance.

Throws:

java.lang.IllegalStateException - if the instance is already initialised.

TransformerException

reset

public void reset()

Resets the Assembly for re-initialisation and use with other characteristics. This method always succeeds.

update

public byte[] update(byte b)
              throws TransformerException

Convenience method that calls the method with same name and three arguments, using a byte array of length 1 whose contents are the designated byte.

Parameters:

b - the byte to process.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

See Also:

update(byte[], int, int)

update

public byte[] update(byte[] in)
              throws TransformerException

Convenience method that calls the method with same name and three arguments. All bytes in in, starting from index position 0 are considered.

Parameters:

in - the input data bytes.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

See Also:

update(byte[], int, int)

update

public byte[] update(byte[] in,
                     int offset,
                     int length)
              throws TransformerException

Processes a designated number of bytes from a given byte array.

Parameters:

in - the input data bytes.

offset - index of in from which to start considering data.

length - the count of bytes to process.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

lastUpdate

public byte[] lastUpdate()
                  throws TransformerException

Convenience method that calls the method with same name and three arguments using a 0-long byte array.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

See Also:

lastUpdate(byte[], int, int)

lastUpdate

public byte[] lastUpdate(byte b)
                  throws TransformerException

Convenience method that calls the method with same name and three arguments, using a byte array of length 1 whose contents are the designated byte.

Parameters:

b - the byte to process.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

See Also:

lastUpdate(byte[], int, int)

lastUpdate

public byte[] lastUpdate(byte[] in)
                  throws TransformerException

Convenience method that calls the method with same name and three arguments. All bytes in in, starting from index position 0 are considered.

Parameters:

in - the input data bytes.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.

See Also:

lastUpdate(byte[], int, int)

lastUpdate

public byte[] lastUpdate(byte[] in,
                         int offset,
                         int length)
                  throws TransformerException

Processes a designated number of bytes from a given byte array and signals, at the same time, that this is the last push operation for this Assembly.

Parameters:

in - the input data bytes.

offset - index of in from which to start considering data.

length - the count of bytes to process.

Returns:

the result of transformation.

Throws:

java.lang.IllegalStateException - if the instance is not initialised.

TransformerException - if a transformation-related exception occurs during the operation.