simple oracle v2

SimpleOracle2.sol

pragma solidity ^0.4.10;

contract SimpleOracle {
    // 增加owner
    address owner;
    // 增加responder
    address public responder;
    mapping(uint256 => bytes) responses;
    
    // 設定owner
    function SimpleOracle() {
        owner = msg.sender;
    }

    // owner才能使用的
    modifier onlyOwner() {
        if (msg.sender != owner) throw;
        _;
    }

    // responder才能使用的
    modifier onlyResponder() {
        if (msg.sender != responder) throw;
        _;
    }
    
    event QueryEvent(uint256 _id, bytes _query);

    // 設定responder，並限定owner才能使用
    function setResponder(address _responder) external onlyOwner {
        responder = _responder;
    }
    
    function query(bytes _query) external returns (uint256) {
        uint256 id = uint256(sha3(block.number, now, _query, msg.sender));
        QueryEvent(id, _query);
        return id;
    }
    
    // 限定responder才能使用
    function _queryCallback(uint256 _id, bytes _response) external onlyResponder {
        responses[_id] = _response;
    }
    
    function getResponse(uint256 _id) external constant returns (bytes) {
        return responses[_id];
    }
}