Nested lists with streams in Java8

Question

I have a list of objects A. Each object A in this list contains list of object B and the object B contains list of Object C. The object C contains an attribute name that i want to use to filter using java 8.

how to write the code below in java 8 using streams to avoid nested loop :

C c1 = null;
String name = "name1"
for (A a: listOfAObjects) {
    for (B b: a.getList()) {
        for (C c: b.getPr()) {
            if (c.getName().equalsIgnoreCase(name)) {
                c1= c;
                break;
            }
        }
    }
}

Answer 1

You can use two flatMap then a filter then you can pick the first one or if no result return null :

C c1 = listOfAObjects.stream()
        .flatMap(a -> a.getList().stream())
        .flatMap(b -> b.getPr().stream())
        .filter(c -> c.getName().equalsIgnoreCase(name))
        .findFirst()
        .orElse(null);