How to search in a List of Java object

Question

I have a List of object and the list is very big. The object is

class Sample {
    String value1;
    String value2;
    String value3;
    String value4;
          


        

Answer 1

You can give a try to Apache Commons Collections.

There is a class CollectionUtils that allows you to select or filter items by custom Predicate.

Your code would be like this:

Predicate condition = new Predicate() {
   boolean evaluate(Object sample) {
        return ((Sample)sample).value3.equals("three");
   }
};
List result = CollectionUtils.select( list, condition );

Update:

In java8, using Lambdas and StreamAPI this should be:

List result = list.stream()
     .filter(item -> item.value3.equals("three"))
     .collect(Collectors.toList());

much nicer!