Most efficient way to see if an ArrayList contains an object in Java

Question

I have an ArrayList of objects in Java. The objects have four fields, two of which I\'d use to consider the object equal to another. I\'m looking for the most efficient wa

Answer 1

If you are a user of my ForEach DSL, it can be done with a Detect query.

Foo foo = ...
Detect query = Detect.from(list);
for (Detect each: query) 
    each.yield = each.element.a == foo.a && each.element.b == foo.b;
return query.result();