design_pattern_desicions.md

Design Patterns

The following Design Patterns were used in the project:

Restricting Access

Some functions in the project can be used only by the owner of the contract. This helps to prevent unwanted changes. For example:

function chengeToken(address _token) public onlyOwner() {
	tokenAddress = _token;
}

Mortal

The project uses OpenZeppelin's contract Destructible to provide Mortal Pattern functional. It gives an ability for the owner to destroy the contract and move it from blockchain if it is necessary.

Circuit Breaker

The project uses OpenZeppelin's contract Pausable to provide Circuit Breaker Pattern functional. It gives an ability for the owner to stop some functions in the contract if it is necessary. For example:

function createEvent(...) whenNotPaused() public {
	...
}

Fail early and fail loud

Functions in the project check the condition required for execution as early as possible in the function body and throw an exception if the condition is not met. It gives the ability to reduce unnecessary code execution in the event that an exception will be thrown.