A few problem about instances are that Equals method doesn’t provide true if even they contain same values. So trying to override Equals method provide much more slower than reference equality.
While i was thinking point of performance, i thought that it is stupidly to create 2 instance which is same but not same memory adress. If i can avoid to create same instances with different references will increase performance and help to compare references will be more easy than write custom Equal methods.
For example:
I have Coordinate class Which hold chess board coordinates.So i need only Coordinate[8,8] array for represent all cordinates of board. Instead of create instances, i can create all instances then my factory method can return them.
Cooardinate.Get(2,3) instead of new Coordinate(2,3)
First is static class’s static method which returns pre-defined coordinate in given values.
Another advantage is that we will not spend time to create and collect garbage objects in memory. All of them is pre-defined already. Also we can provide unique GetHashCode for instances in easy and fast way like 0 for [0,0], 1 for [0,1]….
Isn’t it worthy to try ? this idea would make coding harder write or understand ? Is there any such a pattern ?
Well, shortly what is disadvantages of this way ?
This is a good solution and in certain situations can save you a lot of time and memory. The main drawback is that it gets really complicated if your objects are mutable. If that is not the case, then this is really not that bad. You just have to make sure that all instances are obtained from the same factory. You do not even have to create all the instances in advance, but can make the class create a new instance when a particular set of parameters is requested for the first time (basically lazy-loading).