What actually happens with the constructor is that the runtime uses type data generated by the compiler to determine how much space is needed to store an object instance in memory, be it on the stack or on the heap. This space includes all members variables and the vtbl. After this space is allocated, the … Read more
No, using the constructor to initialize your JUnit test fixture is technically equal to using the @Before method (due to the fact that JUnit creates a new instance of the testing class for each @Test). The only (connotational) difference is that it breaks the symmetry between @Before and @After, which may be confusing for some. … Read more
Use ConstructUsing this will allow you to specify which constructor to use during the mapping. but then all of the other properties will be automatically mapped according to the conventions. Also note that this is different from ConvertUsing in that convert using will not continue to map via the conventions, it will instead give you … Read more
You cannot instantiate final fields in the constructor body. There is a special syntax for that: class Point { final num x; final num y; final num distanceFromOrigin; // Old syntax // Point(x, y) : // x = x, // y = y, // distanceFromOrigin = sqrt(pow(x, 2) + pow(y, 2)); // New syntax Point(this.x, … Read more
A constructor must return an instance of the class it ‘constructs’. Therefore, it’s not possible to return Promise<…> and await for it. You can: Make your public setup async. Do not call it from the constructor. Call it whenever you want to ‘finalize’ object construction. async function run() { let topic; debug(“new TopicsModel”); try { … Read more
tl;dr Use a factory in situations where you don’t necessarily want to return a new instance of the class itself. Use cases: the constructor is expensive, so you want to return an existing instance – if possible – instead of creating a new one; you only ever want to create one instance of a class … Read more