Search Function in Java Data Structure

Question

I have created a large amount of People beans and was wanting to store them in some kind of data structure where I would be able to search for particular types of People beans (e.g. People beans with a last name of "Sanchez") as fast as possible (I don't want to use a DB by the way). Is the only way to loop over my beans and test currBean.getLastName().equals("Sanchez") for each bean?

I would like to be able to do something like the following:

List<PeopleBean> myPeople = myBeansDataStructure.getAll(new PeopleBean("John", "Sanchez", 36),
                            new Comparator<PeopleBean>() {
                                @Override
                                public int compare(PeopleBean b1, PeopleBean b2) {
                                    // search conditions
                                }
                            });

and have it return a collection of beans matching the search. My searches will always be of the same 'kind', i.e., I will be either searching for beans with a particular last name, first name, or age (or some permutation of the three) so could something using an overridden equals method in the bean be used?

Karthik T · Accepted Answer · 2013-09-03 04:44:44Z

2

I am surprised this isnt there in the library.. or is it?

Anyway, you can write your own

public interface Condition<T> {
    public bool satisfies(T t);
}

And write a generic searcher, which goes through the entire and applies this function to each of them and returns you a new of only the ones that return true.

answered Sep 3, 2013 at 4:44

Karthik T

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2 Comments

Josh M Over a year ago

Java 8 provides similar functionality; see my answer as a reference.

Karthik T Over a year ago

@JoshM Yup I saw that.. Nice rep number by the way :P

Josh M · Accepted Answer · 2013-09-03 04:50:53Z

2

You can use Java 8 (This is under the assumption that myBeansDataStructure is a Collection of some sort.):

List<PeopleBean> myPeople = myBeansDataStructure.stream().filter(person -> person.getLastName().equals("Sanchez")).collect(Collectors.toList());

Or you could try something like this:

List<PeopleBean> myPeople = myBeansDataStructure.stream().map(PeopleBean::getLastName).filter(lastName -> lastName.equals("Sanchez")).collect(Collectors.toList());

edited Sep 3, 2013 at 4:50

answered Sep 3, 2013 at 4:45

Josh M

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1 Comment

Karthik T Over a year ago

:( some mean upvoter broke your leetness.. guess I can +1 now

Ruchira Gayan Ranaweera · Accepted Answer · 2013-09-03 04:43:59Z

0

You can try this

    List<PeopleBean> list=new ArrayList<>();
    for(PeopleBean i:list){
        if(i.getName().equals("whatEverName")){
            //do something 
        }
    }

answered Sep 3, 2013 at 4:43

Ruchira Gayan Ranaweera

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