ch.epfl.dedis.byzcoin.transaction

Class Instruction

java.lang.Object

ch.epfl.dedis.byzcoin.transaction.Instruction

public class Instruction
extends Object

An instruction is sent and executed by ByzCoin.

Constructor Summary

Constructors

Constructor and Description
Instruction(ByzCoinProto.Instruction inst)
Instruction(InstanceId instId, byte[] nonce, int index, int length, Delete delete) Use this constructor if it is a delete instruction, i.e.
Instruction(InstanceId instId, byte[] nonce, int index, int length, Invoke invoke) Use this constructor if it is an invoke instruction, i.e.
Instruction(InstanceId instId, byte[] nonce, int index, int length, Spawn spawn) Use this constructor if it is a spawn instruction, i.e.

Method Summary

Modifier and Type	Method and Description
String	action() Outputs the action of the instruction, this action be the same as an action in the corresponding darc.
InstanceId	deriveId(String what) This function derives a contract ID from the instruction with the given string.
static byte[]	genNonce() TODO: define how nonces are used.
Delete	getDelete()
int	getIndex()
InstanceId	getInstId() Getter for the instance ID.
Invoke	getInvoke()
int	getLength()
byte[]	getNonce()
List<Signature>	getSignatures()
Spawn	getSpawn()
byte[]	hash() This method computes the sha256 hash of the instruction.
void	setSignatures(List<Signature> signatures) Setter for the signatures.
void	signBy(DarcId darcId, List<Signer> signers) Have a list of signers sign the instruction.
Request	toDarcRequest(DarcId darcId) Converts the instruction to a Darc request representation.
ByzCoinProto.Instruction	toProto() Converts this object to the protobuf representation.

Methods inherited from class java.lang.Object

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

Constructor Detail

Instruction

public Instruction(InstanceId instId,
                   byte[] nonce,
                   int index,
                   int length,
                   Spawn spawn)

Use this constructor if it is a spawn instruction, i.e. you want to create a new object.

Parameters:

instId - The instance ID.

nonce - The nonce of the object.

index - The index of the instruction in the atomic set.

length - The length of the atomic set.

spawn - The spawn object, which contains the value and the argument.

Instruction

public Instruction(InstanceId instId,
                   byte[] nonce,
                   int index,
                   int length,
                   Invoke invoke)

Use this constructor if it is an invoke instruction, i.e. you want to mutate an object.

Parameters:

instId - The ID of the object, which must be unique.

nonce - The nonce of the object.

index - The index of the instruction in the atomic set.

length - The length of the atomic set.

invoke - The invoke object.

Instruction

public Instruction(InstanceId instId,
                   byte[] nonce,
                   int index,
                   int length,
                   Delete delete)

Use this constructor if it is a delete instruction, i.e. you want to delete an object.

Parameters:

instId - The ID of the object, which must be unique.

nonce - The nonce of the object.

index - The index of the instruction in the atomic set.

length - The length of the atomic set.

delete - The delete object.

Instruction

public Instruction(ByzCoinProto.Instruction inst)
            throws CothorityCryptoException

Throws:

CothorityCryptoException

Method Detail

getInstId

public InstanceId getInstId()

Getter for the instance ID.

Returns:

the InstanceID

setSignatures

public void setSignatures(List<Signature> signatures)

Setter for the signatures.

Parameters:

signatures - the signatures to set

hash

public byte[] hash()

This method computes the sha256 hash of the instruction.

Returns:

The digest.

toProto

public ByzCoinProto.Instruction toProto()

Converts this object to the protobuf representation.

Returns:

The protobuf representation.

action

public String action()

Outputs the action of the instruction, this action be the same as an action in the corresponding darc. Otherwise this instruction may not be accepted.

Returns:

The action.

toDarcRequest

public Request toDarcRequest(DarcId darcId)

Converts the instruction to a Darc request representation.

Parameters:

darcId - the input darc ID

Returns:

The Darc request.

signBy

public void signBy(DarcId darcId,
                   List<Signer> signers)
            throws CothorityCryptoException

Have a list of signers sign the instruction. The instruction will *not* be accepted by byzcoin if it is not signed. The signature will not be valid if the instruction is modified after signing.

Parameters:

darcId - - the darcId

signers - - the list of signers.

Throws:

CothorityCryptoException - if there's a problem with the cryptography

deriveId

public InstanceId deriveId(String what)
                    throws CothorityCryptoException

This function derives a contract ID from the instruction with the given string. The derived instance ID if useful as a key to this instruction.

Parameters:

what - - the string that gets mixed into the derived instance ID

Returns:

the instance ID

Throws:

CothorityCryptoException - if there's a problem with the cryptography

getNonce

public byte[] getNonce()

Returns:

the nonce of the instruction.

getIndex

public int getIndex()

Returns:

the index of the instruction - should be always smaller than the length.

getLength

public int getLength()

Returns:

the length of the instruction - should be always bigger than the index.

getSpawn

public Spawn getSpawn()

Returns:

the spawn-argument of the instruction - only one of spawn, invoke, and delete should be present.

getInvoke

public Invoke getInvoke()

Returns:

the invoke-argument of the instruction - only one of spawn, invoke, and delete should be present.

getDelete

public Delete getDelete()

Returns:

the delete-argument of the instruction - only one of spawn, invoke, and delete should be present.

getSignatures

public List<Signature> getSignatures()

Returns:

the signatures in this instruction.

genNonce

public static byte[] genNonce()

TODO: define how nonces are used.

Returns:

generates a nonce to be used in the instructions.