Question

I would like to know if exist any desing pattern for filtering elements base on some criteria (for example their UUIDS). I ended up in my code with things like this :

if(meetsSomeCriteria(thing))){
     doSomething()
}

For instance, in my code I am filtering some elements based on their id by using a map :

if(!mymap.containsKey(myObject.getId())){
       doSomething();
       mymap.put(myObject.getId(), myObject);
   }

The problem is that this kind of code everywhere in the program. I would like to know if a design pattern can help me and give some hint/examples.

Thanks !!

Answer 1

You can use the CollectionUtils from apache commons
-collections. Something like:

Collection matches = CollectionUtils.select(collection, new Predicate() {
    public boolean evaluate(Object object) {
        // evaluate predicate
    }
});

Internally, it most likely just iterates over the collection and executes the predicate, but it saves your the boiler-plate code.