Contract class.

[Vineet77]

Branch: contracts
Module: client

Implement the Contract class in Contract.java. The class is based off of the Contract struct in Project Aurum.

The Contract Class will have the following instance variables.

• Version: An unsigned 16 bit integer.
• Sender Public Key: This will be have a type of org.bouncycastle.crypto.params.ECPublicKeyParameters. Look at the Contract test to see an example.
• Signature: an array of bytes
• Recipient Public Key hash: an array of bytes.
• Value: an unsigned 64 bit int (use java.math.BigInteger for this)
• State nonce: an unsigned 64 bit int (once again use BigInteger for this)

All values must be valid (ex: version cannot be negative or exceed 2^16), so you will have to check these values and throw an IllegalArgumentException.

There should be the following getter functions:

BigInteger getValue(); 
BigInteger getStateNonce(); 
ECPublicKeyParameters getPublicKey();
byte[] getRecipientPublicKeyHash(); 
byte[] getSignature();
int getVersion(); 

The following setter functions:

setValue(String); 
setStateNonce(String);
setSignature(byte[])
setVersion(int)
setRecipientPublicKeyHash(byte[])
setPublicKey(ECPublicKeyParameters)

Also have the following function

boolean isSigned();

that returns true if signature is not null.

NOTE: Pass in strings for value and state nonce, so internally they can be passed into BigInteger. Look at

project_red/client/src/main/java/sigblockchain/projectred/client/Contract.java

Line 22 in dcc7b21

this.value = new BigInteger(value, 10);

as an example.

All unit tests must pass (run .\gradlew test).

If you have any questions, don't be afraid to ask me.