In multi-stage business processes, code execution mustadhere to specific stages. This can be achieved through time-based or action-based dependencies. The former denotes stages solely based on elapsed time. This pattern prohibits calling a function until a specific time is reached on the blockchain, represented by a delayed condition relation in DCR graphs.The simplest form of this pattern is modeled directly using a delayed condition DCR relation.
// SPDX-License-Identifier: MIT pragma solidity ^0.8.0;
contract TimeConstraintExample {
address public owner;
bool public activity0Executed = false;
bool public activity1Executed = false;
uint256 public activity0ExecutionTime;
modifier onlyOwner() {
require(msg.sender == owner, "Only the owner can call this function");
_;
}
constructor() {
owner = msg.sender;
}
function executeActivity0() external onlyOwner {
require(!activity0Executed, "Activity0 has already been executed");
activity0Executed = true;
activity0ExecutionTime = block.timestamp;
}
function executeActivity1() external onlyOwner {
require(activity0Executed, "Activity0 must be executed first");
require(block.timestamp <= activity0ExecutionTime + 1 hours, "You can only execute Activity1 within 1 hour of executing Activity0");
require(!activity1Executed, "Activity1 has already been executed");
activity1Executed = true;
}
}
