Ethereum Supple Chain Demo

Calculator.sol

pragma solidity ^0.5.1;

contract Calculator {
    int public num;

    constructor() public {
        num = 1;
    }
    
    function getNum() view public returns(int) {
        return num;
    }
    
    function add(int x, int y) public pure returns(int) {
        return x + y;
    }
    
    function sub(int x, int y) public pure returns(int) {
        return x - y;
    }
    
    function setNum(int x) public {
        num = x;
    }
}

SupplyChain.sol

pragma solidity ^0.5.1;
import "github.com/OpenZeppelin/zeppelin-solidity/contracts/math/SafeMath.sol";

contract SupplyChain {
    using SafeMath for uint;

    // Entities
    enum EntityType {PRODUCER, PROCESSOR, DISTRIBUTER, RETAILER}
    struct Entity {
        string name;
        EntityType entityType;
    }
    mapping (address => Entity) public entities;
    mapping (address => uint) entityNumGoods;
    
    // Goods
    enum GoodStatus {PENDING, SOLD}
    struct Good {
        string name;
        GoodStatus status;
    }
    Good[] public goods;
    mapping (uint => address) public goodToOwner;
    
    // Events
    event NewEntity(address entityAddress, string name, EntityType entityType);
    event NewGood(uint goodId, string name);
    event GoodSold(uint goodId, string name);
    
    // Modifiers
    modifier isProducer(address _sender) {
        require(entities[_sender].entityType == EntityType.PRODUCER);
        _;
    }
    
    modifier isNotDuplicateEntity(address _sender) {
        bytes memory _name = bytes(entities[_sender].name);
        require(_name.length == 0);
        _;
    }

    // function to initialize an entity
    function initEntity(string memory _name, EntityType _entityType) public isNotDuplicateEntity(msg.sender) {
        entities[msg.sender].name = _name;
        entities[msg.sender].entityType = _entityType;
        emit NewEntity(msg.sender, _name, _entityType);
    }
    
    // function to initialize a good
    function initGood(string memory _goodName) public isProducer(msg.sender) {
        uint id = goods.push(Good(_goodName, GoodStatus.PENDING));
        goodToOwner[id] = msg.sender;
        emit NewGood(id, _goodName);
    }

    function transferGood(uint goodId, address _to) public {
        goodToOwner[goodId] = _to;
        entityNumGoods[msg.sender].sub(1);
        entityNumGoods[_to].add(1);
    }
    
    function makePayment(address payable _to) public payable {
        require(msg.value > 0);
        _to.transfer(msg.value);
    }
    
    // get all goods that belong to an entity
    function getGoodsByOwner(address _owner) public view returns(uint[] memory) {
        uint[] memory result = new uint[](entityNumGoods[_owner]);
        uint counter = 0;
        for (uint i = 0; i < goods.length; i++) {
          if (goodToOwner[i] == _owner) {
            result[counter] = i;
            counter++;
          }
        }
        return result;
    }
}

pragma solidity ^0.5.1;import "github.com/OpenZeppelin/zeppelin-solidity/contracts/math/SafeMath.sol";

contract SupplyChain { using SafeMath for uint;
// Entities enum EntityType {PRODUCER, PROCESSOR, DISTRIBUTER, RETAILER} struct Entity { string name; EntityType entityType; } mapping (address => Entity) public entities; mapping (address => uint) entityNumGoods; // Goods enum GoodStatus {PENDING, SOLD} struct Good { string name; GoodStatus status; } Good[] public goods; mapping (uint => address) public goodToOwner; // Events event NewEntity(address entityAddress, string name, EntityType entityType); event NewGood(uint goodId, string name); event GoodSold(uint goodId, string name); // Modifiers modifier isProducer(address _sender) { require(entities[_sender].entityType == EntityType.PRODUCER); _; } modifier isNotDuplicateEntity(address _sender) { bytes memory _name = bytes(entities[_sender].name); require(_name.length == 0); _; }
// function to initialize an entity function initEntity(string memory _name, EntityType _entityType) public isNotDuplicateEntity(msg.sender) { entities[msg.sender].name = _name; entities[msg.sender].entityType = _entityType; emit NewEntity(msg.sender, _name, _entityType); } // function to initialize a good function initGood(string memory _goodName) public isProducer(msg.sender) { uint id = goods.push(Good(_goodName, GoodStatus.PENDING)); goodToOwner[id] = msg.sender; emit NewGood(id, _goodName); }
function transferGood(uint goodId, address _to) public { goodToOwner[goodId] = _to; entityNumGoods[msg.sender].sub(1); entityNumGoods[_to].add(1); } function makePayment(address payable _to) public payable { require(msg.value > 0); _to.transfer(msg.value); } // get all goods that belong to an entity function getGoodsByOwner(address _owner) public view returns(uint[] memory) { uint[] memory result = new uint; uint counter = 0; for (uint i = 0; i < goods.length; i++) { if (goodToOwner[i] == _owner) { result[counter] = i; counter++; } } return result; }}